4 Jul
2006
4 Jul
'06
12:31 p.m.
On Tuesday 04 July 2006 02:48 pm, der Mouse wrote:
Possibly, though I find Chuck Guzis's guess that it's boiling varnish
somewhat more plausible.
If this is one that has openings at the bottom, under the chassis, you may
find a puddle of "stuff" under there...
Either that or disconnecting all secondary wires. :-(
I have two or three other old scopes in storage as well as the DuMont, an
Eico 425, a Paco SS-50, and a Precision S-100. One of these has a CRT with
an open filament, and one has a transformer in which the primary opened. I
keep hoping I'll run across a replacement some time, but no luck so far...
Good luck with that one!
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
[oscilloscope power transformer failure]
I assume the popping noises are the sounds of the transformer
windings distorting with the heat. Just a thought - does anyone know what happens to a
steel-core
transformer if its core goes above its Curie temperature? While I
don't think it got anywhere near the Curie temperature of plain iron
(about 1000?K - and paper catches fire at something like 500?K), I
don't know the Curie temperature of transformer-core metal....
Curie temperature is when something that's magnetized loses it. Cores are not
normally magnetized, except during operation, so I wouldn't worry about it.
I expect
you've now got a very dead transformer on your hands :-(
That's what I fear too. :( I haven't done anything with it, yet; I've
been at work all day. When I get back home I'm going to trace out a
schematic of everything the transformer feeds, mostly meaning the power
supply, to tell whether the suggestion of pulling all tubes really will
remove all load from the transformer. (I expect it to, given the
apparent absence of semiconductor diodes, but am not about to count on
it without checking.) Maybe
somewhere like the CHM would be worth contacting to see if
they've got an identical 'scope from which someone can take voltage /
current readings and allow you to build a replacement supply for
yours.
I may do that, but first I'm going to see if I can get voltage
measurements off mine my removing all load. If necessary I'll cut
wires; even if this transformer works in isolation, I am not about to
try to run the 'scope off it for more than moments, so I definitely
will be cutting wires to remove it at some point.