On 1/6/23 15:47, Jerold Kress via Jukebox-list wrote:
I happened to have a similar electrolytic cap with the same specs so I replaced it to see if the OA2s would relit. I also replaced the 6X4 with one from a working guitar amp in case that was the issue. The new cap & the fuse blew in less than a minute. (Note that I had run the unit with the original bulging cap for a lot longer earlier while trying to figure out what was wrong and the fuse didn’t blow. The new cap is shorted/The original cap is not shorted.)
Electrolytic capacitors rarely fail catastrophically unless subjected to reverse polarity or substantial overvoltage. Note that this is a negative supply and C512, C514, C515, and C521 are installed with the positive to ground.
In many circuits heater-to-cathode shorts of 6X4 rectifiers can cause issues but this isn't the case with how it's wired here.
I'd replace all of the electrolytics and ensure they're installed with the correct polarity.