[Hallicrafters] Hot resistors in HT-40

[Bill Gerhold]

A 10 watt resistor in normal operation will get very hot.  So hot, it can
burn your fingers very easily.  What you are finding may be perfectly
normal.

K2WH

-----Original Message-----
From: hallicrafters-bounces at mailman.qth.net
[mailto:hallicrafters-bounces at mailman.qth.net] On Behalf Of Bill Barfield
Sent: Sunday, August 13, 2006 11:15 PM
To: hallicrafters at mailman.qth.net
Subject: [Hallicrafters] Hot resistors in HT-40

I just bought an HT-40 transmitter at a thrift store.  It is cosmetically in
great shape. I could not find a speck of dust in it. It belonged to the
proprietor's father who died not long ago. I did not ask "Does it work?"  I
figured that for $20, it is worth a shot.

I took it home, gave it a good inspection, pulled out and reinserted the
tubes, etc. There are only two paper capacitors in it and only a few
electrolytics (two of which had already been replaced).  So I decided to try
reforming the capacitors and slowly bringing it up to voltage with a variac.

Starting at 40vac, I let it sit and simmer for a half hour, turned it off,
and felt around for warm spots.  The two big 10K 10W resistors in the power
supply were quite hot to touch.  They only had about 90v across them  I
checked the schematic from BAMA to look for what could be shorted to make it
get hot, but found no good candidates.

I don't want to bring the voltage up any further till I either find the
trouble or decide that a hot resistor is normal.  I have already ordered a
better copy of the manual from the Manual Man to make sure I'm not missing
something.

Any ideas what might be amiss?

Bill
KD4AL

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