Circuit Board help

Seems like there is heat discoloration around toroid and the four power diodes right
next to it and large electrolytic

Tedious but consider hand drawing a schematic, then use DVM R measurements to look
for shorts at various circuit nodes. Or start with diode check on DVM, and confirm each
diode looks like a diode, fwd and rev bias with DVM diode check mode.

Check caps not shorted, always key failures causing other failures.


Regards, Dana.

What is the TO220 device, Q207?

I repaired a somewhat similar unit for a friend last year; that used a TOPSwitch type device for its power supply & that had failed.

The TO220 device looks as if it could also be part of the power supply circuit on your version?

Component EC201 is missing. I don't know if it's by design or it broke off. Look at the solder pads on the back side to see if there are just little cones of solder, or if there are some leads imbedded in the cone of solder.

Hi S,
Diode D201 look discoloured too.
C

I see small soldered leads where EC201 ( Electrolytic Capacitor?) should be.

ZipZapOuch said:

Component EC201 is missing. I don't know if it's by design or it broke off. Look at the solder pads on the back side to see if there are just little cones of solder, or if there are some leads imbedded in the cone of solder.

Click to expand...

I see small soldered leads where EC201 ( Electrolytic Capacitor) should be.
Lacking a schematic, no replacement value can be suggested.

In the top picture, I see no leads in the holes at the EC201 location. With wave soldering, the holes would be filled with solder, even if there was no component. Actually, looking carefully at the back side of the board, I think I see a small chip capacitor across the EC201 pads.
Look at the TO220 device, and check the diodes around the discolored area.
Also, check carefully at the backside of the 4 position DIP switch, seems like there are a lot of things very close to each other, possibly shorting something.

Test the board with a multimeter. There may be a broken trace.