Seargent Gork
New member
I have been working on a GM Delco stereo from 1984, the digital model. It was bareley working when i got it. Poor solder connections through out the whole set. I resoldered every, poor connection i could find and got the display to come on, before the radio would work but the led display was dead. Everything seems to be ok now except one problem I cant figure out.
The stereo sounds beautifull and all speakers have been replaced, after running it for about 10 - 20 minutes really kicking the right channel starts to pop in and out. when i balance to the right only, it is in both front and rear speakers and sounds like a clear but much lower sound and as something louder plays it pops in at full volume, the higher the volume goes the more of the sound plays at normal volume but you can still tell it is not right as it sort of gurgles. turn the radio off 5 minutes and back on and its all gravy again.
I have checked and cleaned the pots, I have visually inspected all solder joints and resoldered those that were questionable. I checked every capacitor i could get my probes on and they were at 100% of their values.
My only thoughts are maybe the heater is leaking heat behind and is overheating the back output transistor (could this be a sign of an overheated transistor?), could the transisor be "about" to fail? (i always thought a typical failure of these was just shorted set or open with no sound in that channel). does anybody have any ideas here? i have pulled the set and disassembled it over 5 times now and im ready to get it right.
Maybe someone has some expert knowledge of amplifier technology and can give me some ideas on where to look based on symptoms. Since the problem only happens when its hot i cant really look with my multimeter for differences in each of the channels with the set off.
Dont want an aftermarket radio, keepin it stock, if i have to ill just buy another radio from the junk car ive been parting out up at the pull-a-part, like to get this one fixed short of ordering new output transistors.
The stereo sounds beautifull and all speakers have been replaced, after running it for about 10 - 20 minutes really kicking the right channel starts to pop in and out. when i balance to the right only, it is in both front and rear speakers and sounds like a clear but much lower sound and as something louder plays it pops in at full volume, the higher the volume goes the more of the sound plays at normal volume but you can still tell it is not right as it sort of gurgles. turn the radio off 5 minutes and back on and its all gravy again.
I have checked and cleaned the pots, I have visually inspected all solder joints and resoldered those that were questionable. I checked every capacitor i could get my probes on and they were at 100% of their values.
My only thoughts are maybe the heater is leaking heat behind and is overheating the back output transistor (could this be a sign of an overheated transistor?), could the transisor be "about" to fail? (i always thought a typical failure of these was just shorted set or open with no sound in that channel). does anybody have any ideas here? i have pulled the set and disassembled it over 5 times now and im ready to get it right.
Maybe someone has some expert knowledge of amplifier technology and can give me some ideas on where to look based on symptoms. Since the problem only happens when its hot i cant really look with my multimeter for differences in each of the channels with the set off.
Dont want an aftermarket radio, keepin it stock, if i have to ill just buy another radio from the junk car ive been parting out up at the pull-a-part, like to get this one fixed short of ordering new output transistors.