OM:
I came across your web page while searching the net. I wanted to ask
you a couple of questions about an amplifier I've recently acquired
from an estate. The amp is a Heath SB-1000, but was kept in a rather
humid basement for a fair period of time. When I applied power for the
first time, it immediately popped the fuses. So, I have been
carefully taking it apart, cleaning it, checking components and their
general availability.
I have come to understand that the Ameritron AL80A was essentially
identical to this machine, so I contacted their customer service
group. I originally suspected a bad transformer, but they pointed
out that the symtoms I experienced may well be due to a bad tube.
There was a web page issued on the successor to the AL80A, the AL80B,
and it did discuss this issue. I was advised to apply power without
the tube (3-500Z) plugged in and see if it still takes out the fuses.
I haven't done that yet, but probably will very soon.
I was reading in your web page of the "getter" technique. That
sounds like a reasonable approach, but I was wondering if you can
speak for that approach yourself. Also, do you have any idea how
long one would have to apply filament voltage in order to drive off
the gassing problem? Are we talking about a matter of minutes or a
couple of hours, or what?
I did take the time to ohm across the transformer, but I didn't see
anything earth-shattering (direct shorts, etc.).
Of course, that does not say what would
happen at high voltage conditions. I thought about disconnecting the
transformer outputs, insulating them well and applying power. Then,
if fuses weren't blown, I could reconnect each output separately and
then see what happened. That seems to be a compatible approach with
the one described in the web page.
When I talked with Ameritron, they stated that a new transformer
could be ordered for about $115 and, a new tube is in the
neighborhood of $180. However, I'm trying to verify each of the
components before I dump money into this beast. Any other
suggestions or ideas?
Thanks, OM.
de WB9UCA.
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