Here's a bad cap

[agedhorse]

I'm going through this right now too. Got 250w Dukane paging amp from the 80's or 90's that pops the main fuse immediately. Found one of the two 6300uf 100v electrolytics is shorted. Absolutely no visible indication of a fault. Years ago I could probably find these caps for $15 or $20. Presently they're are in the $90 range. Too much to put in to an old amp that likely needs other components replaced as well before I would be comfortable putting it back in service. The thing ran non-stop for 20 years (school system) before crapping out.

Axial or radial?

Did you measure (or have) the working voltage of the circuit? I maybe have some, if they fit you can have them.

 

[Relsom]

51mm, radial with the screw terminals Andy. I don't know what the working voltage of the circuit is. It's one of those industrial amps that runs a 70v, 25v, or a 4ohm load. Solid state. The matching cap next to it is not shorted with good deflection but I'm still getting a dead short across the line input with the bad cap and the bridge out of the circuit. Thanks for your generous offer but I'm afraid it would be wasted if that primary tranny is shorted, which seems to be the case.

 

[agedhorse]

Disconnect the transformer secondary and see if the problem remains. If it does, you have just found your new vintage doorstop