# Alpine 7909 dc to dc converter info needed



## jeffp

Hi all, I just got this deck and it is a mess. I believe I can get it up and running again. One big problem, the dc to dc converter has been hacked into. No problem there, but one component is missing, a capacitor. 
Do any of you have a blown unit, or the information so I can verify the missing cap. Also, if someone out there has a blown component, I can reverse engineer the unit, complete a schematic and come up with full documentation provided I have the unit complete, unmolested.
Hope someone can help.


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## jeffp

I started disassembling the converter, and am in the process of doing the schematic. I don't know the part numbers to Q1 Q2 and Ic1. I think I may be able to get the part number to Ic1 from the main board schematic, but Q1 and Q2 mat be a problem. I may be able to figure them out when I get the schematic completed. 
I am also going to look into a new dc to dc converter as well, we will see.


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## ryanr7386

LOL, this brings back memories. I traveled down this same path but gave up after I found a minty working 9. I actually ordered all the caps and an IC from overseas for refurbishing the converter in one I "HAD" ambition to bring back to life.

When you talk with the gentleman I'm going to forward contact info on, ask him about these parts, I gave them to him along with caps etc.


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## jeffp

Ryan, thank you for the information. I sent him an email. I am about half way completed on the schematic for the converter. I have three components that are undetermined, but two are transistors. I believe they are an NPN and PNP complement to drive the FET. The last part appears to be also on the main board, so I will go through the schematic and see what I can find. Right now, that component makes no sense when I have completed that part of the schematic. I have the TL1451A portion of the schematic to finish up, but having the data sheet, that is self explaining and should be relatively easy to get completed. 
I think this is worthwhile to complete, then its off to quick turn circuits to have a board made, buy the components from digikey, and put it together. A schematic sure would be nice to have, one I don't have to make, but it is getting there. I have a Philipp's 6303 RLC meter, so I got all of the SMD cap values. That has been one of the best pieces of test equipment I have ever bought. 
We will see.
Also, I bought a 7903 deck, not the one I mentioned in your message. so the transport should be the same part.
I am hoping all this will benefit others in the future, and get me what I want as well.


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## jeffp

So I am making this schematic for the converter and I can figure out how a transistor for what I thought was IC on the silkscreen. My buddy called me asking where is the schematic, and I said I wasn't done with it yet. I started talking about Q1 and Q2 and how it appears the parts pinout for the component must be wrond because schematically it will not work that way. So I will see about the pinout. Then there was this "IC" component tied directly to the gate of the fet and that looked wrong, and Karl says are you sure it isn't a zener diode, to clamp the gate voltage down to 10 volts? Then it dawns on me to look at the silkscreen again, and it looks like it could be D1 so I check it with my meter, sure enough it is a clamping diode. I just never thought to check it for being a diode! So I will test it for its voltage clamping in a small dc circuit and see where it clamps the voltage to. PROBLEM SOLVED! 
Now I'm really getting excited about this repair. I'm going to design a new dc to dc converter for this unit!


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## ryanr7386

jeffp said:


> So I am making this schematic for the converter and I can figure out how a transistor for what I thought was IC on the silkscreen. My buddy called me asking where is the schematic, and I said I wasn't done with it yet. I started talking about Q1 and Q2 and how it appears the parts pinout for the component must be wrond because schematically it will not work that way. So I will see about the pinout. Then there was this "IC" component tied directly to the gate of the fet and that looked wrong, and Karl says are you sure it isn't a zener diode, to clamp the gate voltage down to 10 volts? Then it dawns on me to look at the silkscreen again, and it looks like it could be D1 so I check it with my meter, sure enough it is a clamping diode. I just never thought to check it for being a diode! So I will test it for its voltage clamping in a small dc circuit and see where it clamps the voltage to. PROBLEM SOLVED!
> Now I'm really getting excited about this repair. I'm going to design a new dc to dc converter for this unit!


Getting interesting for sure! There are allot of 9's out there with dead dc converters! You might be getting a few more jobs out of this little project


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## jeffp

I just finished up the schematic. I am having my friend verify it. Next is the circuit board.


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## jeffp

So after my friend and I went back and forth with the schematic, we were able to hammer out all of the components for the supply. I was not sure on three components for the thing, but after some testing I figured out the parts. The schematic is finished, but there are a number of obsolete parts like the 
TL1451A, well not obsolete, but you have to buy a reel of them. I can order the quantities I want from my china source. The 2SK612 is obsolete also and I did buy 4pcs of that component. the 56uF rubycon caps are NLA but Panasonic sells them, however they are 1.5mm larger in diameter then the rubycon component, that makes it hard to fit them into the supply can. 
The rest of the stuff is no problem getting.

So here is the deal, I have been looking at alternate possibilities, and I believe I have found a part that will sub in just fine, using the stock can, the stock circuit board, maintaining the output filter of the supply, and connecting the new part in place of the old circuitry. 
You see, as I understand it, the dc converter has been a problematic part from the start, so now that we have 20 years of technology improvements, why not just get rid of the supply, and replace it with a new and improved part. 
I have found a part that will fit the bill, and it is a perfect sub. 
The part operates from 9-36 volts. The off to on time is 60 milli seconds, basically a 1/4 second. The part is regulated, and it is switching at 200MHz, well out of the range of any of the FM, AM, and CD oscillator ranges, so there is no problem with any noise in the least. The dc ripple is very good, and the MTBF (mean time between failure) is 65,000 hours. The output is rated at 9 Watts. 
I think that will fit the requirements of the deck, what do you think? and the best part is that it will mount right in the stock can, so size constraints are no problem. 
I am going to look into that and try it on my deck. I want to power it up really bad LOL.


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## vinman

Thank you Jeff for all this goldmine of info 

Looking forward to all the upcoming info .....

Cheers ...... Vincent in Ontario Canada


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## ryanr7386

Jeff, I got a 7998R (Parts Deck) in this past week and I just happened to open up the outboard Dac, I'm almost certian it had 56uF caps in it along with some chokes, IC's and some other items. I'll check again when I return from Minneapolis later this week.


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## jeffp

Hi Ryan, I was able to get the info I needed when I did the schematic for the dc converter. 
I have an RLC meter and I was able to get the choke values, and the caps are 56uf components. the part that was missing on my board was C3 and it is a 56uf component. 
I also am looking into getting the TL1451A component from my supplier. I have located the rubycon capacitors, direct replacements. That turned out to be easier then I thought it would be to source those parts. I have ordered the 
2SK612 transistor, but again, I have decided to go and order some additional transistors from my vendor, if they can get them, NEC also made that component, I was able to get the datasheet for the transistor. 
I now have a resistor parts list for the converter, so doing a repair to this module is complete. I still would like to make a new circuit board, I still have to get on that one. 
I have just been a little busy the last few days, I'm laying down wood floor in the house, a little time consuming.


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## ryanr7386

jeffp said:


> Hi Ryan, I was able to get the info I needed when I did the schematic for the dc converter.
> I have an RLC meter and I was able to get the choke values, and the caps are 56uf components. the part that was missing on my board was C3 and it is a 56uf component.
> I also am looking into getting the TL1451A component from my supplier. I have located the rubycon capacitors, direct replacements. That turned out to be easier then I thought it would be to source those parts. I have ordered the
> 2SK612 transistor, but again, I have decided to go and order some additional transistors from my vendor, if they can get them, NEC also made that component, I was able to get the datasheet for the transistor.
> I now have a resistor parts list for the converter, so doing a repair to this module is complete. I still would like to make a new circuit board, I still have to get on that one.
> I have just been a little busy the last few days, I'm laying down wood floor in the house, a little time consuming.


Ya, laying down the wood is always FUN! :laugh:


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## Robb

I had this one repaired by a local shop. It had the same issues - bad transistor inside the dc/dc converter.

http://www.diymobileaudio.com/forum...udio-discussion/50962-alpine-7909-repair.html


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## jeffp

Hi Robb, I was looking for info on a parts list for the converter. I ended up getting most of the info myself. I took the converter apart and completed a schematic of the part. I had a few unknowns like Q1 and Q2 and D1.
After I completed the schematic, I was able to come up with a part for each unknown component. I now have a complete parts list, and schematic. 
My unit was hacked into in a bad way, and the circuit board was damaged in the process. Now I am in the process of making a circuit board to complete the repair work. 
I also have to find out about getting a flex cable made to go from the laser to the cd player circuit board. I have to call my vendor to see if he makes flex cables along with circuit boards, and if that is the case, then I will have the flex cable made also.
As I said, the one unit was hacked very bad, missing parts, and damaged components, all in the attempt to effect a repair. So I guess the repair did not go as planned, but we will see if I can get it up and running again.
it would be nice to get a deck that someone did not get their destructive hands on.


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## ryanr7386

Jeff, your thread you have started here may prove to be invaluable to those of us who have these time pieces! If you are successful with this repair you may get a lot of Friends


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## Robb

Sounds like Jeff knows what he is doing !


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## vinman

ryanr7386 said:


> Jeff, your thread you have started here may prove to be invaluable to those of us who have these time pieces! If you are successful with this repair you may get a lot of Friends



Yes indeed 


7909 DC to Dc converter .... is there any components on the bottom of the board ?
The large cap is a 180uf 35 volt












Clarion DC to Dc converter ..... coincidentally similiar  , has components underneath and is located in the middle of a larger group of components because it's an outboard












Cheers ...... Vin


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## jeffp

Hi Vinman, I took my unit apart, and it had a 150uF cap for C2. The inductors are 50uH components. My Philips 6303 RLC meter has been one of the best pieces of test equipment I have ever bought. 
It was interesting that the 56uF rubycon caps were rated at 130 degree C and the rest of the components rated at 105 degrees.
I placed an order from my supplier in china for the transistor, and the 1451A components. I had to order some thermistors, and asked about the parts, they had them in stock. So I have 10pcs of each on their way. I also got 4pcs of the 2sk612 transistors from UK today. So as soon as the caps come in I will be rebuilding the converter.
I also made up a complete cap parts list for the 7909 main board, audio board, and the cd transport. I have completed the resistor list for the converter also. I figured what the heck $0.77 for a cut tape of 10pcs each I figured it was a good idea to have those on hand as well. I did notice damaged components, so spend $0.050 and just replace it. You would be amazed at what you can see under a stereo 30X microscope. But, when it comes to SMD components, in most cases I use my microscope to do the work, some of the SMD Ic's are impossible to solder without it. 
I placed the digikey order for the cd transport, converter, and audio board caps, and a mouser order for the main board caps. 
Now on to the volume control. The parts are NLA, but I have a trick up my sleeve to get new parts to fix the volume/balance/fader controls. It is not the easiest way to fix that part, but after all is said and done, it will be new again. The one part/s I can find yet are the bass/treble sliders. I am looking and hopefully I can find some part I can work with to get those "new" again. 
Also, I made a call today and found an outfit that can do the flex circuit board for the cd transport I have that was hacked.


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## jeffp

Here is the schematic of the dc converter for your review. I haven't started the circuit board yet, but I will get on it. I am new to diptrace, so this will be my first circuit board with that program.


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## vinman

I'm wondering if heat build up inside of the shielded case was the cause of components failure 

Thank you for the diagram


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## jeffp

Heat could be an issue, however, the question is, how long does the converter last before it goes bad? These decks are very old, and if it is a matter of the converter going down after say 10 years, then is it really a problem. Electrolytic capacitors dry out, they don't last forever. 
So what is the MTBF of the component? 
I have two units I am working on currently, both units require recapping of ALL of the capacitors on all of the boards, so is it a reliability issue, I say no it is not. True it is a pain in the butt replacing the components, but that is just the way the old ball bounces right?

I support an instrument that has a heated detector, to 70 degrees C and that is how the unit is designed to operate. Those units incorporate ceramic SMD caps, and I have had a year of cap replacements to get the detector to operate correctly and be stable.
So when I replace components, I try to get the longest operating time component, the highest temp rated component for the replacement. That to is a pain, but the reality of the situation, so I just go with it, I really don't have any choice in the matter. 

Parts fail, and it's my job to determine the failure, and take the appropriate steps to get the gear up and running again. The repair is simple, but the difficulty is determining the failure and the cause, that's where the time and effort are, and why I am paid to do my work. 

The only other thing that to me is the most difficult, is determining the man made failures, that is the hardest part to figure out. 

I was doing research for alternatives to repair the volume /fader/balance pot on the deck. I believe I have a viable solution to get new parts for the assembly, but in that process, I decided to unsolder the component. What I found, was that some person had either tried to, or removed the component in the past. Clearly, they used a screw driver in that process. What they did with that methodology was to scrape off the solder mask on two traces that passed under the aluminum part of the component, so that when the component was reinstalled, the component shorted out the two traces, now that is ha hard fix! a tech could literally spend hours trouble shooting that problem. 

Similarly, try trouble shooting a board that has a component installed backwards, I have run into that issue as well, really can take some time for a tech to figure out on a unit that historically has been working. You just don't stop to think someone would install a component backwards, but it does happen. That's why I like to work on gear that has never been touched by someone, it just makes my job all that much easier for the most part.
I've got stories like that, when you figure out an issue due to other peoples work, you just shake your head, and think Damn, they got me again LOL.


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## ryanr7386

vinman said:


> I'm wondering if heat build up inside of the shielded case was the cause of components failure
> 
> Thank you for the diagram


I too often wondered the same thing. Why would they have completely enclosed the converter? Why could you not perforate it to let out some of that heat?


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## jeffp

I believe the dc to dc converter, being a noisy part was shielded to stop RFI/EMI. I have not looked at the switching frequency of the unit, but that would be my best guess.


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## Robb

Caps dry out because of excessive/constant use heat right ?
What if I continue to keep mine in a box ? :laugh:


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## ryanr7386

Robb said:


> Caps dry out because of excessive/constant use heat right ?
> What if I continue to keep mine in a box ? :laugh:


Then it is never ENJOYED!!!


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## Robb

ryanr7386 said:


> Then it is never ENJOYED!!!


Ya, but I enjoy storing it safe and sound inside a box in my house. 
It is rare.
If it gets stolen or damaged, I may never find another !


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## badwhip

this is a real good thread great job. the transistor like what has been reported seems to be the misted failed part in the dc to dc convertor. I alsomfound that the china made 612 doesnt last as long either but that could be the vendor who I got them
from.


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## ryanr7386

Robb said:


> Ya, but I enjoy storing it safe and sound inside a box in my house.
> It is rare.
> If it gets stolen or damaged, I may never find another !


Yep, To each his own as they say huh? That's why they made a pullout version though.


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## badwhip

great job on your work can't wait to see the finaly stuff. the 612 transistor always seemed to be the problem in the dc to dc when there was no sound output. I bought a few that where made in china but they didn't seem to last long as the orginal.


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## jeffp

I got four pieces from UK and they are marked exactly like the one I pulled, not to say that means anything. I also got 10 NEC parts from my vendor in China, so we will see. 
I am still waiting on the rubycon caps and then I will put the part back together and put power to it from my dc supply and see what happens. I don't see any problems. 
I have the new converter from Mouser, so that just may be another option, but I will save that for last. I have to figure the current, and the resistor I will need for the 15 to 10 volt drop. right now I am thinking a 1/2 watt resistor, SMD part should do the trick. I think 15 to 10 volts should drop it way below the noise floor of the converter. I just may do a voltage divider, and that may be the best option to dial in the 10 volt supply voltage to the deck. or use a 10 volt zener and resistor combination and take the 10 volts at the resistor and Zener junction. I have to take a look at the best option for voltage stability.


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## ryanr7386

Can't wait! Keep us posted.


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## jeffp

Ok, so here is the story on the new dc converter. The first stage of the unit will have a 9-36 volt input capacity. That should take care of any low battery conditions in the car.
From that converter, the output will be 15 volts plus and minus rails.
The out put then goes into a LM7910 and LM7810 regulators plus and minus 10 volts out @ 500mA - 1A output regulated and filtered. That should supply the deck with all of the required current it would ever need, and keep the output well below the noise floor of the converter. The output will also be diode protected against turn on current/short conditions. The only other thing I want to look into is an inductor on the outputs, but that may be a non issue. I will talk to my PSU expert and get his take. 
I was hoping to use the old circuit board, but at this point I think it is a waste of time. So I will do a new board, that will fit in the case as before and be done with it. There is plenty of real-estate in the can, so I am going to use it.
I am placing the order for the rest of the parts today from Mouser.


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## jeffp

*Re:dc to dc converter build*

Ok so I got all of the components today for the new converter. I plan on bread boarding it to see how it looks. I will be able to fit it in the same area as the old part from what I can see, but I will jus have to lay out the board. 
The converter may have to be shielded, the little converter daughter board, as it is oscillating at 300Khz, so it may generate noise in the second, third, and forth harmonic that may make noise in the AM bands of frequencies. I will just have to get it put together, and I just may shield it anyway, to keep it out of hands reach, or screw driver reach. 
The output regulators are good for .500 milliamps each with 1 Amp peek power for each device. I haven't looked at the power requirements, but I am sure it will not draw that much current.
The output regulators are 7810 and 7910 Fairchild devices, filtered with 1 uF tant caps. I am not sure, but I think I just may incorporate the 50 milli henry inductors on the output. I will have a talk with my friend about that one.
I will keep you updated, but now I need to get a deck up and running with the old converter. I am still waiting for the caps for that part, what a pain waiting for parts from across the world to get here.


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## jeffp

I have put the stock converter back together and powered it up. what a piece of JUNK! The out puts are so unbalanced. 10.7 volts on one rail and 10.1 volts on the other. 
I haven't loaded the outputs, so that may be the issue, but I expected a little better response from the converter. The unit I have designed, will be 10 volts, both rails.

I have been working on the decks, and haven't gotten them to power up yet. I found a bad component on one main board, that is a pain, $.43 cents for the part, and 7 dollars for shipping. 
I will keep you posted on the progress, but it suffices to say both of these decks are a mess, and the one transport laser cable I will have to manufacture the cable, but I now have all of the parts to make a circuit board to connect the laser cable to the ribbon cable that plugs into the circuit board. Finding the correct connector for the circuit board was difficult, but I have the part now and already installed it on the hacked board and fixed the damaged trace connections.


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## vinman

A massive undertaking ...... thank you for sharing :thumbsup:


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## ryanr7386

vinman said:


> A massive undertaking ...... thank you for sharing :thumbsup:


Ya, What he Said /\


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## jeffp

I powered one unit up today. I was working on the unit that had the Alpine processor chip replaced and got it to come up. I checked the power to the dc converter and it is there. I need to reinstall the converter and see if I get audio out of the unit. So far, the tuner and front panel controls work good.
The second unit needs a transistor, the dc converter repaired, and it looks like one of the front panel control chips are toast, but I will have to trouble shoot that problem. 
Then there is the issue of the tansport to contend with. I think I may have a line on the ribbon cable from the pickup/laser, so that will make my job all that much easier.
Now will it play a cd?


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## ryanr7386

Pics pics Pics


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## jeffp

I was working on the first unit and it is still bad. The dc converter is getting to muck load and going down. So I am still scratching my head on that one. C403 is getting hot and the converter is going down as well. The thing about C403 is that it is connected to ground, and 5 volts through Q828 and it is the supply voltage. So go figure. This is a strange problem, and would appear to be the original problem with the deck. I cant for the life of me figure out why the cap is getting hot, except that it may have excessive ripple and can not filter it. So the real problem has eluded me for the moment.
I just may have to start removing components connected to the dc converter until I find the true problem. 
The deck has no audio output so there is a clue I think.

I decided to work on the second deck, and I was able to get that unit up and running. The radio works just fine, and it sounds good. The cd player on the other hand needs some work to it. I cleaned the switches, and the unit will load a cd, but the relay that lenables the gears to lower the cd on the motor will not operate. When I manually throw the relay the cd lowers, and starts spinning, the display comes up with the cd track and time numbers, but it does not see the CD. The track number will not enable, or the time, and the cd player wants to eject the cd. 
So I will recap the cd PCB, clean the mech, and I think it needs the laser. I am hoping the relay will start working after I recap the board. I did check the relay, and it reads 9 ohms, and verified the switches on the limit and the relay switch. They are good now. I am almost positive the laser is toast.
Progress, but not yet completely working. 
The second deck is going to be a beiotch I think. Nothing is getting hot except the dc converter. I have not verified the relays on the main board yet though. I have new parts on order and am still waiting for those. I am just going to change them period, they are very old and I don't want any intermittent operation.
Anyway, that is about it for now.


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## vinman

Wituout taking anything apart , but only using images off the net it seems that the 7909 , 7915 and 7903 share a lot in common .... as probably do a few other units 

Probably the same CD drive mechanism and other mechanical parts as well , can be swapped ..... as also stated by Ryanr

Do they all share the same laser pickup ? 

Edit : Apparently as per Jeff .... the 7909 and the 7903 have different lasers and driving board , would be interesting to find out what laser is in the 7915 etc.

It's no big secret or current news .... but at the time a lot of CD players used Sony lasers .
The 7909 can be subbed with Sony lasers .... 











Tanx ........ Vin


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## jeffp

I bought the 7903 unit, and it is the same mech, but the laser and circuit boards are different. So I kinda wasted some money there, but what the heck I guess. I will try to sell the 7903 unit on ebay. This has been a learning experience for me, and I have spent a good amount of money to get some answers. The 7909 is the only deck with the big PCB on the bottom of the mech. Also I was hoping to get the ribbon cable off of the 7903, but it is different, and as I said the laser is different as well.
So before I go and change out the laser, I will do the board recap and see where that get me. The mech also needs some work, cleaning up and lube. 
Here is the funny part, the deck smells like old electronic equipment, sounds weird, but I have worked on old equipment that has a smell to it, and this deck has that smell, VINTAGE LOL.


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## SUX 2BU

Forgive my electronics ignorance but why is a converter that takes DC voltage (11.5-14.5V from the battery or alternator) and steps it down to another DC voltage (whatever the deck runs on) get so complicated? Isn't that what transformers are for?

I have two pieces of equipment I'd like to get new power supplies for (an Alto Drive 30 and an Altec Lansing ALC-20) but I'm wondering if that is just too complicated or can I find a universal outboard power supply for each of them?


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## jeffp

Dc to DC converters are used in digital electronics. So the rest of the unit is considered analog. It's a way to isolate the power supply to keep the dc line to a specific set of components clean and noise free.
Dc converters are in most cases also a voltage regulator, this is also done to keep a distortion free amplifier, op amp, what ever it is being used for.

This Alpine unit, has a nominal dc converter, meaning it is not a very good design, it was made to be cost effective. How do I know this, well the converter utilizes a TL1451A Ic for the oscillator, to set the oscillator frequency, a 2.2Uf electrolytic cap was used to get to the oscillator frequency. The problem with this configuration is that it is subject to temperature. The cap will change its value with them variations, when that happens, the oscillator frequency will change. With the change in frequency of the oscillator, the power supply will generate different voltages, which in turn supply the amplifiers in the unit, now weather it is bad enough to affect the power out, or in this case the line level output of the unit is a debatable topic. 
So a dc converter is used for dc voltage regulation, and isolation for the most part.


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## vinman

Tanx Jeff , very informative


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## paganelli

Ciao,jeffp,sono Mauro da Italia,molto interessante la discussione,potrei sapere il numero codice del diodo D1.Il mio convertitore non funziona : i condensatori sono buoni e cosi' anche il transistor 612.Non sono sicuro di Q eQ2 che dovrebbero essere 2sc2712 e 2sa1162. Grazie ,Saluti Mauro


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## jeffp

Ciao Mauro , ho reverse engineering lo schema per il convertitore . Io postare sul forum. Mi piacerebbe sapere il numero di parte di D1 . Credo che ho trovato un buon numero di pezzo per tale componente in tutta la mia ricerca . Ho 99 % completato le parti denominazioni , con l'eccezione di un resistore . Il convertitore stavo lavorando aveva designazioni serigrafia illeggibili . Ora hanno altri convertitori posso verificare tutte le denominazioni parti come il.
Dovrò prendere il tempo per verificare nuovamente le designazioni dei componenti con il circuito buono .
Per quanto riguarda il funzionamento dell'unità . Il mio consiglio è quello di sostituire i condensatori , solo per precauzione statellite . L'unità è più di 20 anni , ed i componenti pure. Non mi fido di un condensatore che vecchio , così sostituendo loro è la migliore politica in generale.
È possibile acquistare Q3 , un transistor FET , dal Regno Unito , e in altri luoghi , ma la componente britannica sembra essere la parte migliore . Pulire il circuito molto bene , come in tutti i casi che ho lavorato , i condensatori sono trapelate al circuito e ha iniziato un processo coorosion lento delle saldature ai componenti.
Cercare di individuare i condensatori Rubycon 130 gradi C . Tali componenti saranno gestire il calore molto meglio allora i componenti di qualità temporanei inferiori .Correrò i fogli dta sui due transistor che hai citato e verificare quale id il componente PNP e NPN .Grazie per l'informazione. Gli ultimi componenti per capire sono D2 e D3 i cant trovare il numero di parte in base alle marcature dei componenti. 

Saluti : Jeff Priddy

Spero che questa traduzione è abbastanza preciso


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## paganelli

Ciao,Jeffp,grazie per la traduzione.I condensatori sono stati cambiati,anche transistor 2sk612 cambiato (buyed to littlediode uk), but this isn't the problem. I think the problem is in Q2(marked LG and in digikey data book it is 2sc2712gr) , Q1 (marked SG and complementari of Q2,databook is 2sa1162gr)and in D1,(i haven't found the code marked on the top of the component).Measuring in working condition,i noted a falling volt tension to 12volt at 0,68 volt after resistor (in your schematic R3) to Q2-D1.I think isnt'n normal.Saluti Mauro Paganelli


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## jeffp

Hj Mauro , i due transistor può essere controllato con il controllo di diodo su un multimetro . Non sono nulla speccial o differenza di un transistor standard. D1 è un soppressore diodo transitoria e può bf controllato il modo asme con il multimetro . Se questi componenti sono buone , mi guardo allo zona oscillatore la Ic , e assicurarsi che il tappo 2.2 Uf è buono . Il 2.2 Uf sarà la parte che regola la frequenza oscillatore del Ic . E controllare la Ic e assicurarsi che sia buono .
Io posto di nuovo lo schema . Ho dimenticato di disegnare il VCC di IC nel primo schema . Credo che il problema è nella zona oscillatore .


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## vinman

Ammazzalo ragazzi state facendo uno scempio ..... non si capisce na mazza :laugh:

Your chewing up Italian so badly I'm crying ..... ehehe

If I can help in translating , let me know 

Cheers ...... Vin


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## paganelli

Hi,Jeff,i tried everthing,but in my opinion ,and for my dc-dc converther, the problem could it be in D1(in your schematic D1 +D2) D1=1n4148 and D2 zener diode 10volt or not?Thank you Regards Mauro


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## paganelli

After control with multimeter D1 is good,Q1 and Q2 could be responsable of failure?I think i buyed 2 pieces of these transistor on internet. Regards Mauro


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## jeffp

Hi Mauro, I should be more clear regarding D1 &D2. the part number for that component is, I believe, digikey part number 641-1319-1-ND manufacturer # CAT54A-G
I am sorry fot the bad translation, I am using the google translator. 

Tell you what Mauro, I will repair the converter for you if you send me the component. 

Let me know if you would like to do that.


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## paganelli

Thanks for asking,but i'll try' repair alone.The diode is BAT54AG double diode,it should be marked, depending manifacturing,"L42"or "E42",but i am not sure,because near D1 is descripted VRD1 with simbol of one normal diode + one zener diode(bat 54ag skkotty double diode is a combination of two normal diode .I think assemble a new converter from dismissing electronic crossover or amplifier . Regards Mauro


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## jeffp

Interesting Mauro, if I can get the marking on top of part, can you find the part number of the component? 
Where are you getting the cross reference information from? 

Also, I have not been able to get the part number of the two D3 and D4 parts. Do you have that part number as well?

I will disassemble a converter and see if I can read the part number of the diode under my microscope.

REGARDS:

Jeff Priddy


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## paganelli

Diode 3 and diode 4 are marked "19", and probabily are 1n19 sckkotty barrier rectifier diode for inverter application.If you find the symbol code of d1,certanly i was able to get the corrispondent part number.Sure,when i disassembled the inverter and clean the circuit with alcool, the code on D1 was delete. Regards Mauro


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## jeffp

ok, well I was not able to get a picture of the component (D1) but I made a JPG of EXACTLY what was engraved on the component top.

Here is the pic. I looked on Google for a part number but was not able find the part number of the component. Maybe you will have better luck.


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## paganelli

Ok, D1 could be mima142w obsolete = baw56w dual diode .Thanks Mauro


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## jeffp

I looked up that part and I don't believe that is the correct component. The schematic is correct the part is a dual diode configuration, not a single component configuration.


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## paganelli

Yes, baw56w is a dual diode configuration as in the schematic, and also bat 54ag is a dual diode configuration.The simbol "MO" in SMD CODEBOOK by google describe MIMA142W and your equivalent is BAW56W. Mauro


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## ryanr7386

I'm GLAD you guys know what your talking about :laugh:


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## Robb

LMAO


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## jeffp

You are funny guys, I worked hard on the schematic of the dc converter, and the diode was the last part I needed to identify. 
So with that done, now I have a complete parts list for the converter.
I was thinking of making the circuit board, but after working on some of the worst converters, I have not had to do a new board. I have been able to repair all of the converters, and some were smoked real good. The power transistor is the trouble area, and fortunately, that is easy to do the repairs to.
So here is the completed schematic, now verified.


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## ryanr7386

Ya, looks like a hell of allot of time and efforts been put into it for sure! Keep it up!


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## topdollar69

Subscribed, I'm glad vinman pointed me to this thread.


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## jeffp

I do have allot of time and effort in these units. Currently, I am looking into the bobbins for the transformer. 
I got a repair unit in and did my normal repairs to the converter powered it up an let the unit run for a while. When I got back the unit was dead, the power transistor was toast again. So I went about to trouble shooting the problem and that was the transformer. I checked it with a LC meter and the readings on the secondary windings were not so good. 
I tried to disassemble the transformer but I knew that was not going to fly, and I was right, the ferrite core broke, so I disassembled the part anyway, and I was right, the windings got hot enough to burn up the wire insulation and short between windings, so it was toast along with two transistors. Really bothered me a little blowing two transistors, but that lead me to a new problem, how to replace the transformer. 
I found one that may work on alibaba I have to buy 2000 pieces, not to bad they ended up costing 28.00 if I can get them paid for and shipped. The company does wire transfer, and I am hoping they will do credit card as well. 
so if that goes good I will be able to build new transformers, what pain right?


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## ryanr7386

That's got to be a PITA! These bobbins you mention are just slightly larger than a pencil eraser as I recall, correct?


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## jeffp

Tat is correct they are small. I do have a transformer turning fixture that I will modify to chuck the small transformer. 
I can do a better job winding the transformer then the original vendor, and who knows maybe they will be more robust. 
The whole thing is a PITA as you mentioned.


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## jeffp

I finally got the transformer bobbins and Ecores on order. I was able to get a sample of 20pcs of each part. I also sourced the wire for the build.
Now I will wait and see how long it takes to come in.

The transformers are becoming a problem. I have had two failed parts in the last two weeks, so since there are no replacement parts, this is becoming an issue with repairs.

I did build a dc converter, and it does work very well, but I am not happy with the heat the regulators are making. The part heat soaks the deck after about 5-6 hours of operation.
I have looked at a alternate dc converter that has the outputs @ 12 VDC in stead of 15 VDC and that just may be the answer to stop the heat issue with the 10 volt regulators. I will order the part and see how it goes.


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## ryanr7386

jeffp said:


> I finally got the transformer bobbins and Ecores on order. I was able to get a sample of 20pcs of each part. I also sourced the wire for the build.
> Now I will wait and see how long it takes to come in.
> 
> The transformers are becoming a problem. I have had two failed parts in the last two weeks, so since there are no replacement parts, this is becoming an issue with repairs.
> 
> I did build a dc converter, and it does work very well, but I am not happy with the heat the regulators are making. The part heat soaks the deck after about 5-6 hours of operation.
> I have looked at a alternate dc converter that has the outputs @ 12 VDC in stead of 15 VDC and that just may be the answer to stop the heat issue with the 10 volt regulators. I will order the part and see how it goes.


I Know I'll probably get shot for even mentioning this but what about mounting the DC converter outside the unit like Alpine done in the units produced starting in the early 90's?


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## jeffp

Well that is one way of dealing with the issue, but I don't think most people will take care to install the unit with the separate PSU for the amplifiers in the unit. I know Alpine did the 7990 unit that way, but it is a much bigger unit then what is need for the 7909. The 10 volt negative rail only draws 66-67ma and the positive rail draws 105-107 ma so we are talking very low wattage.

I did receive the transformer bobbins today, an they fit the current cd converter board pinout perfectly. I have the wire on order and it is on its way to me. Now I can build the transformers and hopefully make improvements on their build. 
I think this is still the easiest way to repair the converters. But maybe I am hard headed LOL.


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## ryanr7386

jeffp said:


> Well that is one way of dealing with the issue, but I don't think most people will take care to install the unit with the separate PSU for the amplifiers in the unit. I know Alpine did the 7990 unit that way, but it is a much bigger unit then what is need for the 7909. The 10 volt negative rail only draws 66-67ma and the positive rail draws 105-107 ma so we are talking very low wattage.
> 
> I did receive the transformer bobbins today, an they fit the current cd converter board pinout perfectly. I have the wire on order and it is on its way to me. Now I can build the transformers and hopefully make improvements on their build.
> I think this is still the easiest way to repair the converters. But maybe I am hard headed LOL.


Ya, and one has to question how far to take these upgrades to not destroy the original design intent as well I suppose. What you have accomplished here Jeff is astonishing, at least to me anyway. I have owned several 9's through the years, not so much here lately due to the aging process of these units. Assuming you'll offer service for these units it is peaking my interest to purchase another. And I think I know where to look by the way 

Keep up the excellent work Sir!


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## jeffp

I enjoy doing the restoration on these units. I am pretty good at it now LOL. I have had very positive responses to the units I have sold and have repaired a number of units as well. 
But you always get that one customer, no matter what happens they are the biggest PITA customer. I just finished up one such customer, and at the end of the day I lost out on 20.00 or so in shipping because he had to ship through the post office, and he ran the costs yada yada yada and he cant understand why I am not to pleased with the transaction, and my abrasive email did not help according to him. So there you have it Rick, I am just difficult to work with LOL. Good riddens dude, I HATE THE POST OFFICE, its right up there with the DMV! 
I'm better now LOL. 
anyway, back to the transformers. I cant wait to build one of them. I have all the equipment to build them, pot them evacuate all of the air out of the windings, and go for it. I have had to build the transformer for a high voltage power supply I market to a customer, so I am just wondering how much my part will change from the original part and how it was made. When I unwound the bad one I could see the part was made very sloppy, so I am thinking the adjust resistor on the converter will have to change also. Thank god for the decade resistor. 
Now all I have to do is figure out how to hold the little sucker LOL, the bobbin is so small, amd without the Ecore it is even smaller. Should be fun.


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## jeffp

I received all of the components for the transformers. I had to reorder the wire as the first wire I bought was JUNK. The insulation was not to my liking. So I decided to use the wire I had on hand and turn two wires in parallel on the primary. That worked out good. I then used the same wire on the secondary. 
The first transformer I turned just like the original transformer, and I had a higher then wanted voltage on the positive rail of the output, 11.7 VDC a little higher then I wanted.
I turned a second transformer and this time I turned two wires in parallel on the secondary winding and it turned out good. the negative rail was 9.99 VDC and the positive rail was 9.86 VDC very close. I still would have liked to se 9.99 on the positive rail. The issue is that the positive rail current draw is about 40 milliamps more then the negative rail, a little hard to overcome with such a small transformer. 
I spoke to my engineering buddy, an he seemed to think I was splitting hairs. I asked him if he thought two or more turns on the positive winding would get the voltages closer, and he laughed, smarty. 
I am happy I was able to get the components to go this work on the converter. Otherwise I would have to tell people Sorry, I cant repair your deck. I did do a new converter, and it works well, but it gets a little to hot for my taste over about 8 hours or so. 
I have new wire coming in to try on the next transformer, so we will see how that goes.


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## ryanr7386

Jeff, any idea what you would charge to do a full recap on a unit?


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## jeffp

Hi rick, do you just want the recap only? I have found most of the units have problems with the transport and need some work on the laser and other work. 
I have been charging 400.00 to do a restoration of the unit, so it is good to go, and reliable, not to mention making the improvements on the audio out. Give me a call (714) 907-6318


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## jeffp

*What to do about a missing cd converter can????*

I have built the transformers for the converter and they have turned out perfect. I am seeing 1/10th of a volt difference in the +10 volt and the -10 volt outputs. I talked to my engineering buddy about it and he said I was splitting hairs, and that was an excellent matching of the two outputs.

Anyway, so the next big problem was I got a unit someone hacked to death, and the RFI can was missing all together. So I went to work on that problem as well. 
I could think of only one thing to do, build an new can. So I just finished up my dies to bend the can with today. Here are a few pictures of the finished product. I made the can from brass shim stock. I will find a source on the copper sheet I need and that should be easier to bend then the brass sheet, but both are perfectly acceptable to use to shield the RFI from the converter. I have to finish it up and drill the holes for the power leads, then assemble it, solder it and seal it with RFI tape, DONE DEAL!


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## vinman

Old School artisan style remedies from Jeff are always amazing and inspiring :blush:

Thank you Jeff for posting the images 

Happy New Year ....... Vin


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## BassnTruck

I understand what you are doing and why but I have to ask.

Have you explored using a premade unit? I have had really good luck using these.


















The one with the heat sinks will to 12amps stock and will do 24amps if you put a larger heat sink on it or a fan.

The second one is rated for 2 amps. The voltage display on this unit is not to be trusted. It is close but does not read the same as my Fluke says, which I trust.

These units are not even expensive at $10 and $6 respectively. I have not gotten any feedback or noise out of the ones I have used.


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## ryanr7386

This is a Vintage, Collectable piece of Audio History he is attempting to restore to Factory specs. I don't think he is going to skimp on quality or look for the easy way around fixing the problem.

Just Sayin.


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## BassnTruck

I guess you missed the first sentence of my post. That or you fail at reading comprehension.

I understand restoring one for whatever reason one chooses. It was more targeted if someone who just wanted one to work and not spend hundreds of dollars on an inherent poor design from the beginning.


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## ryanr7386

Sorry that your a little sensitive there dude but what he is reconstructing actually is a component that is attached to the audio pcb board, inside the unit. I'll let him explain why what your suggesting won't work!


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## jeffp

ok I did not get back to this until now. So I have looked into just buying a component to replace the "poorly designed" part. I in fact did design construct a regulated unit and the part worked very well. 
One problem though, the regulator was running hotter then I wanted it to, and I still had to build an RFI can for the part, or use an old can from a stock converter. 
The components you have listed here are from what I can see, are not isolated grounds. The requirement is a +10 and -10 volt supply voltage for all of the op amps in the unit. The ground isolation is for the noise factor, and even still there is some motor noise I see on just about every unit, way down in the mud, and you cant hear it in the speakers, but my instrumentation has found it.
I did build the part, but in the end it turned out easier to simply repair the stock part, no heat related issues over time, and the part works.

So there you have it, the deck is repaired exactly as Alpine built it, and from its history, apparently many many people did not seem to think it was to inferior to buy and compete with. 
I realize there are "Higher Quality" head units out there, all digital, 24 bit processing, yada yada yada, but this unit has the antiquated analogue outputs, the features that make the unit very easy to operate, and features you cant get from most all other units. 
I don't find that I need to enhance, correct, or modify the audio output in any way, other then using the bass and treble controls on the deck, and that for me is just to cool. I tried a number of alpine components, 3347, 3348, fosgate PA2 and NONE of the components made the unit sound any better. 
So I will stay with my "old school" unit and be very happy doing so rocking down the road with a Fosgate power 650 amp. My hotrod currently does 130dB of crystal clear audio, that WILL make you go deaf, oh the sound of Eric Clapton unplugged like he is sitting right in front of you playing, good enough for me.


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## ryanr7386

Well said!


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## BassnTruck

I was under the impression it was a stand alone dongle hanging off the unit. If it was internal to the single din chassis then the external part would require more work to implement. Apparently that is where the confusion lies.

Carry on.


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## ryanr7386

BassnTruck said:


> I was under the impression it was a stand alone dongle hanging off the unit. If it was internal to the single din chassis then the external part would require more work to implement. Apparently that is where the confusion lies.
> 
> Carry on.


Your comment earlier about an inherent poor design is partially true with these 7909"s. The capacitors inside these sealed boxes he is reconstructing were prone to overheating and shortening the lifespan considerably with these converters.


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## BassnTruck

ryanr7386 said:


> Your comment earlier about an inherent poor design is partially true with these 7909"s. The capacitors inside these sealed boxes he is reconstructing were prone to overheating and shortening the lifespan considerably with these converters.



So it is an external module? I never used the Alpines back in the day. Most of mine were Eclipse units. The majority of my dead head 8v units had a couple boxes hanging off of it. I never looked into what they were back then but it is very possible they were a DC to DC converter.

I know enough about electrical to be dangerous. I am not an electrical engineer, I went the mechanical side.


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## ryanr7386

BassnTruck said:


> So it is an external module? I never used the Alpines back in the day. Most of mine were Eclipse units. The majority of my dead head 8v units had a couple boxes hanging off of it. I never looked into what they were back then but it is very possible they were a DC to DC converter.
> 
> I know enough about electrical to be dangerous. I am not an electrical engineer, I went the mechanical side.


No, it's internal. About the size of a matchbox.


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## jeffp

The confusion is the plastic black box with one yellow, and one black wire in the wire harness. That box (on the J model) is a noise filter that provided the dc converter 12 volts. The difference with the J model (and 30th anniversary) from all of the other models is that box. The dc converter is powered by that dedicated power source in the wire harness. The 7909 and 7909L power the dc converter with the single yellow switched power wire in the wire harness. 
The second power source feed was done to cut down on any internal noise that may have been generated by the unit itself, like the cd spindle motor for example.
hope that clears it up


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## jeffp

*Transformer components Finally!*

I was able to source the transformer bobbin and ecores through one company. I got 30psc and 30 pairs of ecores. Then I started using a number of them, so I tried to get a new order, company is gone, that sucked.
Well I finally was able to find a new company with the components. I bought 100pcs and pairs of ecores. 
I can build 100 transformers now, So now I have every part to build a dc converter from scratch. I haven't made the circuit board, but haven't need to replace a board yet. I have been able to work with every unit and get it working again.


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## JDMM5

I am going to contact you regarding a 30th anniversary unit


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## jeffp

Give me a call at 714 907-6318 if you like. 

REGARDS:

Jeff Priddy


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## JDMM5

I'm James and new to the forum. I sent a PM with a 7909 question but it was quickly disposed of as my post count did not qualify. 

Recently I acquired a 30th edition (Ebay, Canada) with some accessories minus the all important wire harness beyond the mini molex. Basically the headunit with some CD changer interface dongles and nothing else. From all the information I have been able to gather, this unit like the 7909J had an external DC/DC converter included in that harness. Whereas the original pullout model had this inclusive to the unit. Why or how a wire harness would not be included or come up missing is interesting, but so be it.

My main question is the pinout locations (or wire colors) on the mini molex that receive the +10, -10, and audio ground inputs. Most of the other wiring connection details can be found in the downloaded manual. Any information you could provide here would be infinitely appreciated, as I just cannot locate this information online. I'm willing to pay for this information because time is not free, and I fully appreciate that.

As far as the converter itself, that will not present a problem. I'm going to use a commercial 10-15w isolated unit with either +/-12v or +/-15 outs feeding a 7810/7910 pair on a single sided PCB, as I read you had developed one. No one on the planet seems to make a dual 10v converter. Finding an original Alpine is likely out of the question, and the project will be fun.

Thanks,
James M.


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## jeffp

You are correct, no one makes a plus and minus 10 volt dc converter. I did make a good converter, but it was a 15 volt plus and minus. I then used plus and minus Fairchild regulators to get to the regulated 10 volts. I would have preferred a 12 converter, but they to are difficult to find in a 1" X 1" square circuit board. I since have sourced all of the parts to repair the Alpine dc converter. 

People say the converters are a bad design, but not really, if you stop to consider they do last longer then ten years for most units, and the fact that any capacitor is advertised 10 years MTBF you begin to realize that the bad rap the converter got is really from people whining about doing maintenance on their gear. 

I mean it should last forever right. anyway, I have not had to trash one converter because it was to bad to fix, and believe me I have gotten some real gems, converters that someone used a dremel to remove the cover, you know technical stuff like that, usually on the 7909 pullout units. They are ALWAYS in the poorest condition because everybody and their brother tried to FIX them. 

The dc converter you mentioned is not in that harness, but located on the audio board of the unit. what people believe to be a dc converter is simply a dc line filter to power the dc converter in the unit. 

The J model and 30th model are identical, except for the fact the tuners are configured to tune different frequencies, and the 30th unit has green line rca outputs. and that is about it.

Regarding the wire harness. the harness is made up of 11 wires, to power the various functions of the radio, light dimmer, antenna, amp remote on, power, ground, aux remote on and others.

So I hope that answers some of your questions. feel free to mail me at [email protected] if you have any other questions.

REGARDS:

Jeff Priddy


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## JDMM5

Thanks for clearing that up. I was getting some conflicting information from various threads about this. One post of specs from member Robb lists the 30th as having an external converter, while other posts say it does not. I knew you would know with the time investment you have in these units, so thanks for that.

Any recommendation on an aftermarket line filter? I assume any decent quality unit designed for 12v should suffice. I have seen some impressive looking units from China (yes China) on the cheap. One had three stages of various coils and capacitors and appeared industrial quality. That may be overkill though.

-James


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## jeffp

I have found this filter:
https://www.walmart.com/ip/Scosche-10-Amp-100-Watt-Single-Stage-Noise-Filter/10752389
The filter current rating is way overkill, but it is the one unit I can take apart and use my own wiring and it appears the be small enough not to be a bother in the wire harness.
I have not found a good source for the filter Alpine used, I would like to get the correct part for the units that don't have a filter, so far I don't buy units that don't have a harness because of the difficulty I have finding a suitable component, but the 30th anniversary unit is a different story.
I would buy the unit without a harness and figure it out LOL.


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## JDMM5

Unit 021/300 was posted on Ebay 1 week ago with perfect silkscreen and chassis at about 9.25/10 condition. You could tell it had only been installed/removed approx 1 time judging by the light markings that would inevitably appear.

I was doing a random Alpine search as I have a thing for excellent condition 3545's / 35xx amps in general and ran across this unit that had been posted a whopping 6 minutes by sheer luck. To top it off; was under $400. That being the case I'm willing to spend a little time and effort fabricating a harness. I may even go as far a sourcing correct color combinations. Well see how that goes..


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## jeffp

Now that was a find, and 400 really good price for the unit. I have never even gotten close to that for my j models, and my anniversary was a lot of money also. 
I did find a new in line filter that I think will do very well for the units. 

https://www.aliexpress.com/item/Dif...32701700859.html?spm=2114.13010608.0.0.Vxnul8

I ordered 19pcs. I wanted 20pcs, but the shipping went outrageous @ 20 pcs. 
The thing I like about the unit is that I can take it apart and configure it with my wiring and my parts if needed, so that is the closest I have gotten to the Alpine filter, but this one will be just fine I think. I would love to find the exact part, but after 20+ years I don't think that is a possibility.
anyway good find on the 30th.


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