Hey, I recently replaced the belts on my Sony TPS-L2 and was in the process of calibrating the speed with a 3000 Hz cassette. It functioned perfectly for about 5 minutes, but then it suddenly stopped working(while I was calibrating) The cassette is still rotating, but there's no sound output. Additionally, the hotline mic isn't working anymore. Has anyone experienced something similar or have any insights on what might be the issue? Read head or basically the electronics are fried?? Thanks
Most likely some wires got broken off and you have no power to the main PCB (the one that has the amplifiers), hence no sound. So I recommend to check thoroughly starting from the small board with DC in jack (that's where the power gets distributed elsewhere) as it's unlikely anything else failed so suddenly.
Thanks, I can't see broken wires(I'll check even more). How to Check if the main PCB is getting power? (Any diagram for the main PCB?) If there is no broken wires, what would be the issue?
Please download the service manual from here: https://elektrotanya.com/sony_tps-l2_sm.pdf/download.html Note there are 2 variants of TPS-L2 with different PCBs and different schematics, the manual give the serial number ranges in order to identify your own. Check voltage at pin 1 of preamp (IC101/IC201) relative to ground. It should be around 2.6V (can be lower if using NiMH cells). Then the power amp/ripple filter (IC102/IC202) has is also powered on pin 1 and it outputs votlage for the preamp at pin 8. Don't know what the problem can be, cannot guess since I don't have the device in front of me. You need to start measuring voltages, then if those are ok you should start checking the head wires/signal wires. Signal may not get through to the small jack board. You need to take things one at a time and start to eliminate things that are not a problem. You can also have failed capacitors (if you have the model with electrolytic caps), but seems unlikely they suddenly failed.
