# Alpine 7939



## qwank (Aug 4, 2013)

My 7502 has been acting up the past year and it finally died yesterday. I need to replace it and I think I'll go with a cd player this time. The 7939 seems like a good head unit for the money they are selling for and I don't really see anyone posting any problems with them.

My questions are:

Can you hook up an aux input to it through the ai-net?

Does the power antenna lead only power up when the radio is on? I hate the antenna being up when not listening to the radio.

Anyone have one for sale?


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## qwank (Aug 4, 2013)

does anyone have a copy of the manual saved? I keep finding the same link online for it but they're all no good anymore.


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## hurrication (Dec 19, 2011)

I bought one a few months ago from user Fast VW, and he had another one that he was trying to sell. 

Car Audio | DiyMobileAudio.com | Car Stereo Forum - View Profile: Fast VW


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## qwank (Aug 4, 2013)

ok, so I got one off of Ebay, everything work except for the remote turn on and power antenna leads. Please tell me this is an easy fix.


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## qwank (Aug 4, 2013)

I think I found the problem. Found two transistors on the remote and antenna circuits that are open. waiting for new ones to come in.


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## 1996blackmax (Aug 29, 2007)

I actually have two of these units....there is something to be said for old school simple to use HU's. I had it hooked up in my old car to a PXA-H600 processor using the fiberoptic connections. I was also using the KCA-410C versatile link terminal and the KCA-121B. This allowed me to use my iphone & be able to control it from the HU.


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## qwank (Aug 4, 2013)

thanks! why is there 2 ai-net connector? ones on a blue cable, and the other is right on the back of the HU


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## 1996blackmax (Aug 29, 2007)

One is Ai-Net input, & the other output. So you would hook up a changer to the Ai-Net in connection, and a processor to the Ai-Net output.

Not sure why they went this route & later with just a single Ai-Net connection, as the processors of the time had an input for a changer as well.


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## qwank (Aug 4, 2013)

1996blackmax said:


> One is Ai-Net input, & the other output. So you would hook up a changer to the Ai-Net in connection, and a processor to the Ai-Net output.
> 
> Not sure why they went this route & later with just a single Ai-Net connection, as the processors of the time had an input for a changer as well.


oh ok. makes sense. I'm guessing the one on the radio itself is the input, and the one on the blue cable is the output?


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## 1996blackmax (Aug 29, 2007)

Yes, the one on the radio is for a changer input. The one that's on the cable is for use with a processor (out).


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## qwank (Aug 4, 2013)

I hooked up the Ai-net aux cable to the input and nothing happens when I hit the changer button. I tried to ground the mute wire and still nothing. Do I need the kca-410c to get it to work properly?


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## qwank (Aug 4, 2013)

Ok, i went and played around with this again. This time I hooked the aux cable to the blue Ai-net cable and I got sound, however it plays over either the radio or CD player, whichever is on.

No problem, ground the audio interrupt right? Nope, does nothing. So I tried putting power to the interrupt. This time I get "Interrupt" across the display and no sound at all. 

I'm getting closer, Just not quite there yet. I Can't get the Changer button to do anything either with the aux cable hooked up to either Ai-net socket.

Any help?


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## 1996blackmax (Aug 29, 2007)

I've only used it with the versatile link adapter. While in changer mode if I hit band it switches between the changer & the iPod (see's it as another changer). It's been a little while since I used it, but I think that was the way it went. I'll check with my son's car, he has a CDA-7949 in his car with that set up.


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## qwank (Aug 4, 2013)

thanks. They want a ton of money for those KCA-410C on eBay, otherwise I would buy one and try it. I read I could use a KCA-801B also, but can't find one for sale anywhere.


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## 1996blackmax (Aug 29, 2007)

Yeah, they go for bit. I actually bought mine brand new for $25 on ebay a few years back. I saw it & scooped it up quickly.

I may have a KCA-801B....not sure exactly where in the garage though. If I can find it, I will sell it to you.

In the mean time try looking for a substitute for the KCA-801B. I can't remember what company made one, but there was another version that didn't need the trigger wire. It would sense the signal from the inputs.


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## 1996blackmax (Aug 29, 2007)

Double post...


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## qwank (Aug 4, 2013)

1996blackmax said:


> Yeah, they go for bit. I actually bought mine brand new for $25 on ebay a few years back. I saw it & scooped it up quickly.
> 
> I may have a KCA-801B....not sure exactly where in the garage though. If I can find it, I will sell it to you.
> 
> In the mean time try looking for a substitute for the KCA-801B. I can't remember what company made one, but there was another version that didn't need the trigger wire. It would sense the signal from the inputs.


awesome! 

I'll look online for that other adapter. I wouldn't mind running a changer also, so if it's necessary to have one to run the aux input it's not a big deal. Unfortunately, I only have an M bud changer right now, so one more thing I'll have to buy.


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## qwank (Aug 4, 2013)

Is this the other adapter?

P.I.E Aux Input Adapter For Alpine Auxiliary audio input adapter for Ai-Net system (Model ALP/AI-AUX) at Crutchfield.com


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## 1996blackmax (Aug 29, 2007)

Yes, that's the one.


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## qwank (Aug 4, 2013)

of course it's not available anymore.

I found this too, but it's also discontinued everywhere

AUX-JAGCD Auxiliary input Adapter for Select Jaguar with CD Auto Changer :: iPod Adapters & Interfaces

this is the only thing I can find that's still available:

http://www.ebay.com/itm/Digital-Cd-...431?pt=US_Car_CD_Changers&hash=item58ad3e2a1f


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## 1996blackmax (Aug 29, 2007)

Don't give up...try posting in the classifieds to see if anyone has any of these items.


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## upgrayedd (Apr 19, 2011)

good luck with it. I ran aux on my 7940 (only one year newer) with no issues. It was a cheap simple cable, no boxes on it. However I recall it actually being an alpine cable. Hard to remember as this was 12 years ago.


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