Good evening, I have a D6C with no sound output. After researching on the forum, it seems the issue may be related to the DC-to-DC converter’s 11V output. I measured the output and, sure enough, it was 0V. I proceeded to disassemble the converter, but it appeared to be in good condition. I then reconnected the GND and 6V inputs and measured the output again, which was 11V. However, when I connected the 11V output to the PCB, the voltage dropped to 0V. This leads me to believe there is a short somewhere on the board. From my online research, I found that several components have encapsulation issues that could potentially cause shorts. Has anyone encountered this problem before? Is there anything specific I should look out for? Should I try using acetone to remove the casing from the components?
The three potted components on the D6C are the mute module and the two EQ switching modules. You could try removing them first of all, then see if the short disappears, however the 11V rail doesn't go near the EQ modules and a fault within the mute module would be unlikely to cause a direct short between 11V and ground. The pad which the orange 11V wire from the DC-DC converter is soldered onto is surrounded by the ground track and associated black wire connections. It would be worth checking for any loose wire whiskers or solder bridges. Also check any electrolytic or tantalum capacitors on the 11V rail. It is possible to isolate parts of the 11V rail by de-soldering the wires which connect them together. By doing this you can work out on which part of the circuit the short is occuring. Are you measuring a short circuit between the 11V rail and 0V when the walkman is switched off and there is no power to it? If the short is only apparent when the walkman is switched on, try checking C302, between the emitter of Q301 and 0V. It is a 10uF /16V tantalum and these can go short occasionally. Note that C302 is shown but not labelled on the circuit schematic for the earlier version D6C, but is is shown on the PCB layout diagram.
Thanks Deb64 for your detailed reply, I will try to see if I can locate the short with pointers you have provided.
Thanks Deb64, found the short there was a solder bridge between the orange pad and the ground track getting sound now.
