[Hallicrafters] RE: Heybor trannys for Hallicrafters

[GBrown]

Well, I have to jump in here and voice my experience with these
Hallicrafters transformers.  Heybor probably does make a good transformer
BUT....... no amount of stacking is going to cure a heat problem that is
generated by faulty parts in the power supply or other areas of the
circuits.
I have rewound transformers for many years now and find that one of the most
common problem is just plain age. Yes, age. Materials used 40, 50, even 60
years ago or more have lived there life expectancy. Sure, mite of been top
of the line materials then but now, after several years, allot of us are
expecting these transformers to perform like in the good old days. Its not
going to happen. You mite not see or hear anything happening but rest
assured, its happening and I can guarantee you a failure. When is another
question. There are some steps to consider to try and save one of these
trannys for a longer life. First thing is components that draw on the
transformer for performing are to be tested. Yes, old caps mite look good
and test good but believe me, CHANGE THEM. You wont regret it. Second, to
your disbelief, varnish dipping NEVER penetrated into the windings. Honest,
I see it every day. My cure, and it works, is to vacuum dip the transformer
into varnish while the transformer has been heated up. This will draw as
much as possible, varnish throughout the windings. I know, everyone doesn't
have a vacuum tank like I use. Third and probably the hardest to correct is
to BACK OF on the power output. 120 watts, 75 watts, there is no difference
to the ear and your going to thank yourself for it. I know, I am going to
get some more technical answers from a few but these are the basics.
    On another thought. Every rewind I do uses nomex insulation and 200
degree C triple coated magnet wire. I have wound about 17 to 20 of these
trannys in the past 10 years and there all still running today, that I know
of.
Yes, you can add some turns hear and take away some turns there for today's
higher house voltages. You know, it is sooooo easy to bring out a couple of
taps so the owner can change the tap anytime he wishes. This side of town
has 115 volts, where the other side of town has 125 volts. One tap will take
care of this difference and then you can move to the other side of town and
still operate that HT-32 and still not loose any sleep. Sorry for being so
long with this post but just wanted to drive a few points across to us all.
Regards,
Gary...WZ1M