Technics SU-Z650 schematics


2015-08-05 5:31 pm

Someone just gave me a none workking technics su-z650, nothing very special so I just want to see if I can get it working again and maybe give it away. A lot of burned spots on the circuit board cracked some of the solder spots supplying the power to the preamp board. I fixed those and I got sound again. One channel takes some time to come through with a lot of noise but then settles and works fine. I was thinking maybe the volume pot or the relay.

I suspect the fan wasn't working letting the amp get too hot and causing these burned marks but I tested the fan and it works. I measured voltage at the wires going to the fan and that gave me 20mV. I read that this model has some kind of temperature sensor which controls the speed of the fan but is this on the board, controlling the voltage at the fans terminals or should I always have 12V there and is it the fan itself that has a built in sensor ?! Anyway without the schematics I won't get very far so if anyone has those that would be great.