1966 GE PortaColor Restoration

[Dubis7]

Originally Posted by Electronic M

My standard process for tin whisker infested pots is to remove, and dismantle the pot take a toothbrush then fine sandpaper to the metal parts clean everything with a good control cleaner and paper towels, reassemble the pot, check resistance and range with rotation between all terminals and also case metal, and if all is good reinstall.

Okay. I'll give this a try. I'm going to just remove the pot, disassemble it, and deep clean it.

One thing I am sort of wondering about, and I can get pictures of this if you need it: I'm noticing that the pot doesn't have the standard three lugs. Instead, it has one that goes to C2D/the main PCB, and two that connect to ground. That matches the schematic just fine, but since this is unusual, is there anything I should be watching out for as I disassemble?

[Electronic M]

Originally Posted by Dubis7

Okay. I'll give this a try. I'm going to just remove the pot, disassemble it, and deep clean it.

One thing I am sort of wondering about, and I can get pictures of this if you need it: I'm noticing that the pot doesn't have the standard three lugs. Instead, it has one that goes to C2D/the main PCB, and two that connect to ground. That matches the schematic just fine, but since this is unusual, is there anything I should be watching out for as I disassemble?

That just means it is configured as a variable resistor instead of a variable voltage divider...One benefit of this configuration is if one of the end lugs is open but center never goes open you can make the open end lug the grounded one and continue to use it(max and min vs rotation may swap).

[Dubis7]

Okay, well I really went at it with the deoxit on R5. Not seeing any change.

Are we sure this can't be a HV problem? Or maybe a voltage problem? My HV to the CRT is still measuring between 7 and 10 KV. It should be around 15 per the schematic.