Beiträge von Gerrit im Thema „C128 no DC voltage - what can cause this?“

    The solder joints look good... the brown stuff is flux residue and can be ignored.

    The plug you have can be disassembled, there is a metal tab somewhere in the middle of the case that you have to push in slightly, then you can slide the case back.

    You should reattach the ground wire... Good for your health. ;)

    This is a PSU where the step down to a save voltage (20-30V) is handled by the Transformer. The switching regulator then takes this intermediate voltage to generate the +5V. So once you disconnect it from the power outlet, there won't be any dangerous voltages lurking anywhere.

    You should remove the 3 screws (2 on the transformer and one on the PCB) that hold the PCB in place and take it out of the case. Then take a look at the underside of it and upload a photo if possible.

    What kind of square plug do you have? Can it be disassembled or is it molded?

    Here's what I did when I had a dead C128 PSU: Stripped out everything after the rectifier, replaced the capacitor and used an adjustable Regulator based on the LM2596 (from Ebay) instead. Then adjusted the regulator to supply 5.3V on its output which translates to about 5.1-5.0V once it gets to the C128.

    You can now get even smaller and more efficient adjustable DC/DC-converters on ebay cheaply. Those no longer need a heatsink.