Audio Systems: alpine CDA-7875 panasonic CQ-DF802U, alpine cda 7875, ground loop isolator

Question
I have two car cd's with same problem & posibly  caused by same trouble in car. Both had bad grounds to amp. in trunk & burnt radio RCA output grounds inside each radio. It also burnt out the output IC'S in each radio. I replaced each output IC & repaired all burnt foils at RCA jacks. Both radios now work fine on all fuctions except both have no sound from CD only. Tuner audio good on both units at RCA & speaker outputs. Just no audio from CD. Both CD's read & display time running & change tracks fine, just no audio. I swaped CD transports with another alpine deck & now have audio in this one & not in the other. Wondering which IC on CD deck PC board is bad? The D/A conv. or mute circuts on CD PC board? One IC on the panasonic CD deck PC board runs way too hot in less than 30 seconds. Generic # on IC is upd63711gc 0220e3006 . Is that# a D/A conv.IC? I dont have another panasonic unit to swap CD decks to see if problem lies in CD PC board or mother board.  

Answer
Robert,
Most of the time when I install car sound systems, I always try to install a ground loop isolator. This would have prevented you stereos from burning up due to the defective ground wire on the amp. It sounds like the defective ground at the amp caused TOO! much current to pass through the stereos and this also damaged the D/A IC's in the CD decks. I will look up the service data if I have it for your model stereo and I will look up the data for the IC that you gave to see if it is a D/A convertor IC. I will let you know ASAP!

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net