Today starts to work on the unit, deep cleaning on the filthy exterior before dismantling. Carefully remove the 3 main section of the pcb board..tuner, tape control mechanism and audio amp. Troubleshooting focused on the power supply & found the transformer secondary coil was shorted. That is the reason no DC voltage source to power up the board. Alternatively I have to render some modification by using a 5A-12V switching power supply. The unit is now able to power up. First test on the radio and line in, audio output deliver to both sides of the speakers upon the illuminated level led. A big relief at least the amp IC is functional to my expectation which is the main part of this restoration.. Unfortunately the tape portion doesn't seem to respond. Probably the main IC control system could have dead but it's not a concern as long as the line in and radio functional. But I will work on it later time..
To cover some of the deep scuffs, I printed some labels to hide it. More after restoration pictures in a new thread.. http://stereo2go.com/forums/threads/national-rx-c52-resurrection-part-3.8424/#post-65023
