# PPI 900.4 cutting out on occasion, sudden developement.



## carter1010 (Sep 20, 2009)

I have a PPI 900.4 Phantom Series amplifier that just recently began to turn on and off intermittently. Nothing has changed with regards to system wiring or speaker configuration since the initial install. 

If I tap the heatsink of the amp after it turns off, it will turn back on. If I turn up the volume to my normal listening level it will shut off until the volume is backed down or I tap the amplifier. It works fine in the morning when the temperature is cool, but in the afternoon after the car has been in the sun, it does not work correctly. I have two of these amps installed in the same spot in the car. The other one works fine. Initially I thought it was a heat problem until I checked and there was no power or protection light on. Once the amp is tapped or the volume reduced, it immediately returns to normal operation. 

Anyone have any ideas of what I might be looking for that could cause this problem within the amplifier?

Thank you,
Brian


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## Beckerson1 (Jul 3, 2012)

Lose connection inside the amp comes to mind. I would open it up and check all he solder points and/or lose wiring. 

All three of my PPI 900.4's knobs are upside down so IMHO QC is skimping on doing there job.


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## momofx (Oct 17, 2012)

Wow there must be something wrong with a batch of these cos mine started doing that too! Only difference is once mine warms up its fine then but if I give it more than about 60% output from when I first turn it on, it will switch off and on until I lower the volume for a while.

Nice amps but this makes them suck.


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## JAX (Jun 2, 2006)

sounds like solder joint. Tricky or someone will chime in.


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## Beckerson1 (Jul 3, 2012)

Well I'm currently having some more issues just pop up on my current PPI im using to temporarily power a pair of bookshelf speakers kit from PE. 

Like above I can turn the gain up to about %40 and will go into protect for no apparent reason. 

Amps seeing 15V constant the entire time, scope shows no clipping (not really clean, there is some sort of interference). Gets hot to (like Class A/B hot) even with gain all the way down. So something is screwy with the amp 

And I have two in the car in which I've had a issue with the one as far as not wanting to bridge right. 




I'm going to try and set the gain's in car. I am so close to contacting PPI and demanding new amps as these (well the one) clearly has an issue with it.


I mean come on the gain knobs weren't even right. The markings on all 3 I have were Flip Flop'd and the knob was reversed 180 degree's. I paid good money for these and I'm PISSED. 

If PPI won't do anything I will have to talk with Trumpet and see what he can do. Bought two of the three off him. Nothing wrong on his part. It's all PPI. All this crap is just now coming out of the woodwork with these (well the one so far) amps.

Sorry for the rant


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## sirbOOm (Jan 24, 2013)

Was asked to install a PPI 5-channel and when I picked it up, I heard something moving around inside. We never installed it... I'd bet something that was soldered broke off. It was brand new, never been turned on. Looked fine otherwise. My 2-cents.


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## DonH (Jun 25, 2009)

I had a Pold PAD 5channel, same buildhouse as all other philips chipsets from china. the small class d chassis etc. it would shut off randomly as well.


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## Beckerson1 (Jul 3, 2012)

Here is the curve I get from the one in the garage:











The one amp had something loose but we opened it up and it was a bolt head that mounted the board to the amp (1 of 3). It literally sheared off. We removed it and everything seemed to work perfect. That current amp is still in car. Not the one in garage.


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## Wy2quiet (Jun 29, 2010)

Mine died after 3 months. Same thing - something moving around inside when I moved the amp.


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## Beckerson1 (Jul 3, 2012)

Wy2quiet said:


> Mine died after 3 months. Same thing - something moving around inside when I moved the amp.


did you contact PPI about it?

I mean if I can't get anything for these amps I'd be pissed. 


Ya I tried the ones in the car and it went into protect on 47 or 62 of HU. The protect light is on and the blue power light flashes every couple seconds. Once I turn it down it comes back on.

I mean the 360 outputs 8vRMS but I wasn't even close to it.

I'm pissed


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## Wy2quiet (Jun 29, 2010)

Didn't contact PPI since Canada to US shipping would have cost me half the amp. Sold the amp with 3/4 channels working for $50. Absolute garbage, although I am sure there are many that work fine, 1/10 amplifiers with moving parts on the inside (which probably shorted something out) is just unacceptable. The Polk phillips boards seem to have the same thing going on, as there are a lot of refurbs on ebay etc.


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## Beckerson1 (Jul 3, 2012)

Wy2quiet said:


> Didn't contact PPI since Canada to US shipping would have cost me half the amp. Sold the amp with 3/4 channels working for $50. Absolute garbage, although I am sure there are many that work fine, 1/10 amplifiers with moving parts on the inside (which probably shorted something out) is just unacceptable. The Polk phillips boards seem to have the same thing going on, as there are a lot of refurbs on ebay etc.


Ya I'm contacting PPI about this. Its bad when I have 3 amps from two different sources be bad.


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## ATOMICTECH62 (Jan 24, 2009)

Sounds like an output filter cap.I have never worked on the PPI's but 50% of the time that is the problem with class d amps.While that waveform is typical of most class d amps it does show output ripple that the filter caps are suppose to clean up.


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## Beckerson1 (Jul 3, 2012)

ATOMICTECH62 said:


> Sounds like an output filter cap.I have never worked on the PPI's but 50% of the time that is the problem with class d amps.While that waveform is typical of most class d amps it does show output ripple that the filter caps are suppose to clean up.


I can check the one amp for this issue but I need to know what I'm looking for. If anyway possible you can give me an idea (show me if possible) what it looks like and a simple test I can do to test the cap. As long as its not hard I am willing to fix it myself


Would this explain why the amp cuts out after a certain point (40% in my case)?


Actually I do have a picture of the amp's internals from when I first got it.










The red circle was the screw head that was sheared off. I never touched it, have witnesses. They are a double sided board so IDK how to take this panel out to get to the other side. At this point and time I never put power to it.


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## ATOMICTECH62 (Jan 24, 2009)

Most class d amps use at least a 12db/oct lp filter on the output devices.Some use 18-36db/oct filters.There is always a small coil and cap for each channel.They will be connected to the speaker terminals or a relay between the speaker terminals and the outputs.The caps are usually bipolar(nonpolar)with no black stripe on one side like all the other electrolytics.However I have seen some amps that use 2 normal electrolytics back to back to form a bipolar cap.There will be basic layout.A 4 channel will have 4 identical coils and caps and maybe even 4 relays all connected to the speaker terminals.

Look for caps that are swollen or leaking.And check the small coils for heat damage(discolored)and wiggle them to see if they are soldered to the board good.Coils breaking off the boards are another major problem with class d amps.

Yes bad filter caps cause the amps to shut down and reduced output.If not replaced they will usually explode if the output don't give out first.


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## Beckerson1 (Jul 3, 2012)

ATOMICTECH62 said:


> Most class d amps use at least a 12db/oct lp filter on the output devices.Some use 18-36db/oct filters.There is always a small coil and cap for each channel.They will be connected to the speaker terminals or a relay between the speaker terminals and the outputs.The caps are usually bipolar(nonpolar)with no black stripe on one side like all the other electrolytics.However I have seen some amps that use 2 normal electrolytics back to back to form a bipolar cap.There will be basic layout.A 4 channel will have 4 identical coils and caps and maybe even 4 relays all connected to the speaker terminals.
> 
> Look for caps that are swollen or leaking.And check the small coils for heat damage(discolored)and wiggle them to see if they are soldered to the board good.Coils breaking off the boards are another major problem with class d amps.
> 
> Yes bad filter caps cause the amps to shut down and reduced output.If not replaced they will usually explode if the output don't give out first.


Ok ya I will check it out.


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## ATOMICTECH62 (Jan 24, 2009)

On that amp they are using poly caps.The 8 red ones.The 4 square gray things next to the red caps are the coils.The 2 black rectangles are the relay's(must be dual ganged)and the 2 circular coils right next to the terminals are also output filter coils.They are dual ganged also.Inspect the 4 blue resistors next to the relay's also.
That broken screw you referred to could also be a problem.Class d amps are very sensitive about signal grounding.90% of class d mono blocks will not play music without an RCA ground.Look and see if any traces on the board are connected to that point.


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## Beckerson1 (Jul 3, 2012)

This is the only thing I can see that may be an issue.

Nothing seems burned, swollen, leaking


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## Beckerson1 (Jul 3, 2012)

Not sure it might be


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## Thumper26 (Sep 23, 2005)

I hate to hear this. Been running three in my car for a year with no problems.


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## ATOMICTECH62 (Jan 24, 2009)

Those red caps need to be resoldered.The broken screw is connecting that smd cap to ground so it should be reconnected in some way if you cant replace the screw.


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## Beckerson1 (Jul 3, 2012)

Thumper26 said:


> I hate to hear this. Been running three in my car for a year with no problems.


I know there have been many people surprised when I tell them this.


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## Beckerson1 (Jul 3, 2012)

ATOMICTECH62 said:


> Those red caps need to be resoldered.The broken screw is connecting that smd cap to ground so it should be reconnected in some way if you cant replace the screw.


So in most cases the ones in car are in the same situation. The screws are not busted on those. But I'm sure the soldering isn't good on those either.

I will see if I can get my soldering gun in there but I can't guarantee anything. Its not exactly small.


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## Beckerson1 (Jul 3, 2012)

Well I can't do anything myself as it looks like I have to remove everything (including the frets or whatever you call them). 3rd picture up in this thread its the screws closest to the keyboard.

So I'm really mad atm.


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## Beckerson1 (Jul 3, 2012)

Well I can't do anything myself as it looks like I have to remove everything (including the frets or whatever you call them). I don't have the product to replace those. Unless thermal paste is ok to use. 3rd picture up in this thread its the screws closest to the keyboard.

So I'm really mad atm.


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## jimmybee1108 (Apr 26, 2011)

Damn. Was really hoping to pick up a p900.4 and either p600.2 or p1000.1. Not so sure now


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## The Dude (Mar 24, 2007)

I have a 600.2 and 1000.1 en route to me, hopefully I will not run into any issues......


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## Beckerson1 (Jul 3, 2012)

jimmybee1108 said:


> Damn. Was really hoping to pick up a p900.4 and either p600.2 or p1000.1. Not so sure now


Well. If it eases your mind a little bit my friend bought one to install in another gentleman's car. Everything is perfect with that amp. Gains are right and everything. No issues with it.


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## momofx (Oct 17, 2012)

Just to update - I noticed mine does it when it is first powered up AND if I go to over 80% of the full clean output (it will shut off). Now what is wierd is that if I let the amp "warm up" for about 10 mins - I can give it 100% output and it will never cut off no matter how hot it gets, etc.... really wierd...

I might get rid of this crap and go with something else for my mids - maybe a good old Class AB


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## JAX (Jun 2, 2006)

momofx said:


> Just to update - I noticed mine does it when it is first powered up AND if I go to over 80% of the full clean output (it will shut off). Now what is wierd is that if I let the amp "warm up" for about 10 mins - I can give it 100% output and it will never cut off no matter how hot it gets, etc.... really wierd...
> 
> I might get rid of this crap and go with something else for my mids - maybe a good old Class AB



Interesting indeed. 

I'm loving my good old overbuilt yet compact a/b power. It's cured me mostly of the amp swapping.


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## Beckerson1 (Jul 3, 2012)

Lol I'm running my good ol AB right now. Has never failed me. Just doesn't give the power I need for my mids.

120W vs the 35W I'm giving them. I've got a A/B Nendo in which will cure me of the lack of power.


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## carter1010 (Sep 20, 2009)

My problem was remedied after I tightened all the screws to my power inputs, specifically, resetting the separate block that lets you run 4 gauge to the amp. I have had no problems since.


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## momofx (Oct 17, 2012)

carter I tried that too! Tightened em down and even put a drop of loctite in there - still no go. This certainly has to be some sort of quality control issue and manufacturing defect on their side. It's sad to see complaints like this about a brand like Precision Power but I guess the old PPI will always be number 1...

As I mentioned, it works great once its "warmed up" lol. How silly is that?! Like an old 70's car on a cold day!


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## Beckerson1 (Jul 3, 2012)

momofx said:


> carter I tried that too! Tightened em down and even put a drop of loctite in there - still no go. This certainly has to be some sort of quality control issue and manufacturing defect on their side. It's sad to see complaints like this about a brand like Precision Power but I guess the old PPI will always be number 1...
> 
> As I mentioned, it works great once its "warmed up" lol. How silly is that?! Like an old 70's car on a cold day!


Worst thing is. PPI won't acknowledge it. All I get is:

"Were sorry your out of warrenty. We can fix it but you need to pay shipping (there and back) and repair fee's." 

I say hell no. I have 3 amps that need looked over and diagnosed. Shipping alone for all three will cost almost a complete new amp from them. I'm talking with a member on CACO who repairs amps and working with him to see what I can do to get it fixed.


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## TrickyRicky (Apr 5, 2009)

Sounds to me like QC issues, also could be design related. 

Hate to say it but this is what happens when corners are cut to make products cheaper and affordable to the public.


Am willing to bet more will start popping up with issues, just wait and see.


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## SkipNJ (Mar 12, 2009)

Just installed my P900.5 today. It turns on and works fine, but that power/ground guage adapter block didn't seem to fit right and I had to be careful to make sure everything was aligned right when I tightened down the screws. Everything else seems ok.


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## copene (Oct 19, 2013)

Any updates on the 900.4 cutting out issues? I had one start cutting out after about 8 weeks and the replacement started cutting out after a few hours. Like others have mentioned, seems to work ok in the mornings most times and then ****s the bed. Is it a bad batch or is this a known issue plaguing this awesome little amp?


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## JAX (Jun 2, 2006)

TrickyRicky said:


> Sounds to me like QC issues, also could be design related.
> 
> Hate to say it but this is what happens when corners are cut to make products cheaper and affordable to the public.
> 
> ...



maybe I can get Dave to chime in and see what he says from a design standpoint...since he actually knows how to do so


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