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#1
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B&K 465 weak voltage
I've had my B&K 465 for about 8 years now. It's actually been a really good tube tester and I've used it to rejuvenate quite a few tubes. I noticed that anytime G2 voltage is 50 volts on a tube it tests very bad. So today on a hunch I used the tube pin out and checked the G2 voltage what should be 50 volts was only 20. I think the original components are starting to fail. I attached the schematic below. Judging from the drawing other than the Transformer they seem to be what makes up the main power supply for the entire tester. Am I right in thinking that if I replace the two 5 microfarad capacitors I should be able to bring this thing back ? To me they seem like they're the main filters and maybe they're getting weak? Or am I more likely to have to go after the 4 Diodes just before them.
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#2
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There's not that much to the unit, so while you're replacing the caps on general principles, it would be quick and easy to check the 100 ohm and 470k ohm resistors. I would feel dumb if I didn't take the opportunity.
Also, C-3 and C-4 (50 mfd) and R9 and R10. Last edited by old_tv_nut; 08-15-2026 at 06:42 PM. |
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#3
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Quote:
Well unless Im reading the schematic wrong C3 and C4 seem like they're just for rejuvenating a tube. I don't mind replacing them. But I wanted to see if I can get the voltage back into spec before doing the rest of the recap. What do you think? |
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#4
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Fine to do the ones in the power supply first and then check. My thought though is they're all the same age, and it's not a lot of parts, so why not bring them all up to date?
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