4 Jul
2006
4 Jul
'06
5:34 a.m.
der Mouse wrote:
> Small popping noises are not a normal operating sound for that 'scope.
> I used it enough to know _that_. Then, looking over at it, I saw that
> (at least some of) the tube filaments were dark, and there was nothing
> on the display.
> Turns out it is the power transformer (not
surprising, in view of the
> dark filaments). It continued making popping noises well over a minute
> after I unplugged it, and for a few seconds I was even mentally making
> sure I knew where the nearest fire extinguisher was, since it gave the
> impression it might actually catch fire.
yikes! Sounds like the potting is boiling or burning off...
> It's now been at least ten minutes since I
unplugged it, and the
> transformer is still too hot to rest my hand on for longer than about a
> quarter-second. And, it is giving off odours which I am also quite
> certain are not part of normal operation.
> Tomorrow, I'm going to try turning it on (very
briefly, with a
> current-limiter in series with the primary) to see if it's healthy
> enough to give me useful voltage measurements. The only winding whose
> voltage I am confident of is the one that drives the tube heaters.
> Based solely on wire count I am sure there are at least two others -
> and based on the application I expect at least one for the final anode
> voltage and one for power to most of the circuits.
First, I'd disconnect the filter caps and meter them for shorts! Any
semiconductor diodes? Might be one or two of those shorted too. Might be
you shoulda reformed those OLD caps before powering up on full AC, or
replaced them.
Anyone know a
good supplier for ten-kg power transformers? :-(
YES! Well since this has to be a custom design,try here
-- http://www.electra-print.com/
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