# P880PRS - Dead Internal Amplifier?



## corsagt (Sep 6, 2010)

I recently purchased a used P880PRS from a member on DIYMA. It was sold with the common pico fuse problem, but this wasn't an issue for me as I'm only interested in using the powered outputs. I wired everything up, and it all worked fine and sounded quite good. I left it just "sitting" in my dash all week, and it worked fine all week. I removed the HU to install the mounting tabs for my dash, put it back in, and now I have nothing out of the internally amplified outputs. 

Mute isn't on. The internal amplifier is set to "on" in the settings menu. I've tried FM/CD/Aux sources. I've switched between the NW and STD settings for the internal crossover. I used a HT amp to test each driver individually (they all work). I reset the "sound" settings in the system menu. I did a hard reset by pressing the button on the display. 

I even disassembled the player and jumpered across the pico fuse near the pre-outs. I couldn't find any other pico fuses on the board. I also checked to see if I used fasteners that were too long (though they were only 8mm) for the dash brackets, but there was nothing that they would have interfered with to feasibly cause this problem. 

The pre-outs have the signal coming through. 

Does anyone have any ideas what the problem could be? Did my used Pioneer HU just lose the internal amplifier from lightly handling it and turning it on it's side on my bench? This just seems absurd...


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## JAX (Jun 2, 2006)

if you sell let me know


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## corsagt (Sep 6, 2010)

It's been three days and 85 views and nobody has any suggestions...what gives?

Am I asking the wrong questions or posting in the wrong section/forum? 

I'd really like to get this figured out.


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## Thumper88 (Dec 1, 2006)

Do you have an oscilloscope? Sounds like you need to investigate the built-in amplifier.
Never taken my p880prs apart, but I assume it's just a couple chip amps. Find out what they are, look up the data sheet. See if the pins designated on the data sheet are getting power. Check if audio signal is making it to the ICs...

Other than that...you could always use it as a dead head.


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## corsagt (Sep 6, 2010)

I don't have a scope personally, but getting my hands on one should be pretty easy. 

I saw a couple microprocessor-looking chips on the board, but I wasn't sure if they would be used in amplification or just the interface software. 

I've got a good friend who is an electronics technician (though knows virtually nothing about stereo equipment) who offered to replace some ICs if needed.


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## JAX (Jun 2, 2006)

I know someone who knows whats what in that deck. or you can just sell it to me. or I can trade you a new Eclipse XA2000 amp


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## corsagt (Sep 6, 2010)

After hours of diagnosis, I neglected to pick one of the low-hanging fruits early on...

I had removed and reinstalled one of the woofers. They are the popular Dayton 7" woofers, going into doors that originally had 6.5" drivers. The terminals must have shorted across the door when I reinstalled it.

Apparently Pioneer head units cut all of the amplifier channels when one of the outputs is shorted.


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