Power Transfromer Post Mortem

[Daver]

I have an amp here that I built a few months ago that blows the AC fuse. I have removed all the tubes, bulb and anything that the secondary powers. it blows the fuse instantly. I can't measure any connection to ground that isn't supposed to be there. I removed the transformer and measured from primary to secondary and from the windings to each other and to the core. I don't get anything indicating a direct short. Can a power transformer fail in a manner that isn't easily measured?
Dave

[olddawg]

I am asumming that you are talking about the PT. Sure...The primary windings can internally short to each other. Especially if the tranny got hot and the lacquer insulation smoked. How many ohms does the primary read on the 1 ohm scale? Have you tried plugging the tranny into an ac source completely removed from the unit? I would use a pigtail fuse though.

[Daver]

Yes, the PT, even though my title say "transfromer" instead of transformer. I haven't tried plugging it into the wall outlet out of the amp. The primary measures 1.4 ohms. A new Hammond I have sitting here measures 1.1 ohms. Thanks olddawg.
Dave

[Daver]

Any other input? Thanks.
Dave

[Diablo]

If you have a smoked filter capacitor, it'll blow fuses. Does it blow fuses when on standby or only when powered up? Here's a troubleshooting link.

http://www.geofex.com/ampdbug/fuseblow.htm

[Daver]

Diablo,
I've seen the Geofex troubleshooting link before. It's a good one for sure. The filter caps are fine. As I mentioned in my first post, I removed any and all loads on the secondary and the AC fuse blows instantly. It's the power transformer that's bad, I'm just curious as to how to test it after the failure. Measuring windings seem to give "normal" readings. Thanks!
Dave