On Tue, 18 Oct 2005 23:11:07 -0500, "les" wrote:

Hello...
I have an old photo studio speedlight (Speedotron) that is
starting to buzz and overheat. Actually, it's the AC mains
XFMR, but as the unit warms...and the transformer starts
to bubble......yikes!, amazingly the strobe unit still works.
I'm obviously in need of a new transformer.
I know that old transformers tend to delaminate, but what other
maladies do they suffer?
Can they just overheat from failing insulation, or other aging issues?
I realize rising current draw could cause similar behavior, but I'm
assuming age as the factor in the transformer for now. Is this a foolish
assumption? (25 years old)

Les KA9GLW

Assuming it is not being overloaded bubbling yet operational,
implies some shorted turns in one of the (usually) hgher voltage
windings as they have the higher resistance coils. So, it;s
overloaded but still supplies enough voltage to be useable.

Even assuming no abuse through overheating, insulation can dry up
and cause problems especially with many tapped coils,