Questioni think it's definately an IC chip, even though the head unit does have MOSFET written on the face. The chip is black, around 1 1/2" long, 3/4" deep and 1/4" thick. mounted standing vertically towards the rear of the unit, close up agaisnt the thick aluminium rear plate (heatsink?).
Soldered into the main board it has a total of 25 legs coming from one side, 12 in row next to 13 in row. this sound about right?
now, before i change it, i need to be sure this is the problem.. how can i test it? ive read about signal tracers and scopes to listen to the signal at each leg of the amp... i do not have one of these but i may be able to fabricate something to a similar effect.
also, the chip does no have any numbers/identity codes on the rear face? the front face is tight up against the unit chassis and i will not be able to see it until i have removed the chip... im guessing information will be here?
thanks again
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thanks for the quick reply! ideally i do not want to use aux amps becuase I lose functionality of the unit itself! how can I determine what type the output devices are? do you know where I can download a service manual for the unit?
regards
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Hi. I have a pioneer deh p6700mp head unit installed. It was working fine all the way up to max volume, 62. After a while I noticed the sound deteriorating at high volume, and the problem has worsened - it crackles even at low volume and refuses to play anything above 30. The problem becomes even worse when you turn up the bass. Fading and balance have no influence on the problem.
I have checked all wiring and speakers and everything seems OK. I plugged in my old pioneer deh p3500mp with the same configuration and ISO lead and it works perfectly.
The amp however, connected through the SW-OUT with RCA's powers my subwoofer fine at ALL volumes.
Have the 4 main channels blown inside the head unit? If so, can I repair these myself?
I am a mechanic with a couple years experience in automotive electronics, confident with a soldering iron. I do not want to send the unit out to Pioneer only to have it sent back with a huge repair bill!
Thank you for your time!
Regards, Mani
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sounds like the internal amp is shot. repairing auto stereo is so expensive due to it being so hard just to open it enough to find problem. if your output devices are ic's instead of discreet transistors or mosfets, i might try replacing them, if i could get to them without destroying the unit in the process.. if you have pre-out jacks for the front and rear, aux amps might be your most economical option.
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ic outputs will be 4 or so 10 or more legged on one side devices mounted to relatively large finned heat sinks, probably to the rear or sides of the unit, whereas transistors and mosfet outputs only have 3 legs, and they'll be in pairs mounted to the heat sinks. you can do a google on your model plus the word schematic and you'll find sources, search farther and you might find some info for free, but i've paid $25. for printable on line scats a few times for diff. junk i'm working on.
Answerthere really should be some letters and numbers on the face of the chip, sometimes they're very faint and small, but here's the kicker...sometimes they remove the numbers so you can't identify it unless you have the proper schematic. fun, huh! but that sounds like it might be it.
