Hi all,
First post here, need a little help. I have a Pioneer SX-780 that I recently found in my Dad's old stuff after he passed away. I'd like to get it working and use it for FM stereo listening and it's been about 25 years since I heard it play.
The unit powers on and lights up on the front, all the controls appear to be working. When hitting the power switch I do hear a prominent relay click. Once the unit is on at a random time thereafter it will start playing sound...usually around 2 minutes or so and then it will stay on for anywhere between 5 seconds and 10 minutes but then the sound will shut off(front lights stay on always). When it does this the wattage meters for the speakers go to zero as well. When the unit is working I can swap between AM/FM/AUX, etc without issue and without any scratchyness, I don't think there are any control issues...it sounds like something internal and non-physical. I've tested all the fuses, I've done the preliminary voltage checks on the darlingtons and I've inspected for buldged capacitors...that is about the extent of my knowledge from googling on this forum. I've also re-soldered the transistors with the silver aluminum heatsinks that appear to be prone to failure from other posts. The symptoms have persisted throughout this troubleshooting. Also I might be crazy but it seems the unit is more likely to start playing sound if upside down or on the side lol...I know probably crazy. Tapping on the components and bumping the chassis doesn't seem to affect anything. I would imagine this is something with the 'protection circuitry'?
Any help would be greatly appreciated.
Thanks,
Alan
First post here, need a little help. I have a Pioneer SX-780 that I recently found in my Dad's old stuff after he passed away. I'd like to get it working and use it for FM stereo listening and it's been about 25 years since I heard it play.
The unit powers on and lights up on the front, all the controls appear to be working. When hitting the power switch I do hear a prominent relay click. Once the unit is on at a random time thereafter it will start playing sound...usually around 2 minutes or so and then it will stay on for anywhere between 5 seconds and 10 minutes but then the sound will shut off(front lights stay on always). When it does this the wattage meters for the speakers go to zero as well. When the unit is working I can swap between AM/FM/AUX, etc without issue and without any scratchyness, I don't think there are any control issues...it sounds like something internal and non-physical. I've tested all the fuses, I've done the preliminary voltage checks on the darlingtons and I've inspected for buldged capacitors...that is about the extent of my knowledge from googling on this forum. I've also re-soldered the transistors with the silver aluminum heatsinks that appear to be prone to failure from other posts. The symptoms have persisted throughout this troubleshooting. Also I might be crazy but it seems the unit is more likely to start playing sound if upside down or on the side lol...I know probably crazy. Tapping on the components and bumping the chassis doesn't seem to affect anything. I would imagine this is something with the 'protection circuitry'?
Any help would be greatly appreciated.
Thanks,
Alan