He's not exaggerating Frank!! You have NO idea how many options and possibilities there are!! You REALLY need to post a picture of some kind. you just can't say "pot" and expect anyone to go by that alone, and even the data off the OEM part is sketchy.
I think it was satisfactory. We already had a fuzzy schematic, that seemed to show 25K, and given the application, it should probably be a linear taper. Given it's position in the negative feedback path of an op amp means it cannot be passing any significant power, so anything with the right resistance should be sufficient (and the available pots are 500 mW, far more than sufficient, and insulated to 300V and it maybe sees 3-4 volts).
His readout off the pot was B25K and what is probably a date code (23 week of 1977, sounds about right). B is linear taper as expected, and its's 25K as expected. The only other important characteristic is the shaft type, Frank can certainly tell whether it is smooth, serrated, or D-shaped (and smooth or d-shaped would probably work OK with his smooth shaft knob with a set screw). I think it is probably too long, but that could be cut off, or just left alone.
The much better question is why the pot is suspected - it's a good guess, the one moving part that might wear out or get dirty. Maybe some contact cleaner would fix it. The original was a Noble pot, known for pretty high quality, and very unlikely to wear out in this application. But getting dirty, that is probably to be expected. But I would also replace the electrolytic capacitors before anything else.
I have worked on a Northeast power panel (with no schematic) before, and I think the problem was the output transistor, which does have to pass a lot of current.
Brett
Topic: Where may I purchase a pot to repair a glow driver? (Read 1776 times)