[Hammarlund] HQ-180 fixes
Craig Roberts
crgrbrts at verizon.net
Sat Mar 19 12:26:11 EST 2005
Hi Jeff,
Please replace all paper capacitors and the electrolytics. Look for the
"Black Beauty" type, too. They're paper caps in a large brown or black
case with color code stripes -- they look like very, very larger
resistors -- and square brown caps that look like big micas with the
brand name "Micamold" on them. They're not micas at all. Like the Black
Beauties they're really cleverly disguised paper caps. The Black
Beauties and Micamold caps (as well as the wax paper one) are almost
always bad, or soon will be. A search of the Internet will turn up
photos and color codes for these plastic encapsulated capacitors. I
can't remember if the HQ-180 has any in it. I don't think so, but it's
a tip worth remembering for other projects.
Don't bother with the solid state rectifier substitution unless you
really want to. There's no real operational advantage to it. But, if
you really want to "solid state" the easy and elegant way, purchase a
5U4 Copper Cap from Ted Weber. It's got the dropping resistors in it and
inrush current protection, too. Visit http://www.webervst.com/ccap.html
. Ted's a good guy and a fellow ham. I've used his Copper Caps in my
Collins 516F-2 power supply and several other devices.
For cleaning pots, switches, the bandswitch, etc., use DeOxit (available
from a variety of sources, including Antique Electronic Supply
(www.tubesandmore.com). Use this product sparingly -- especially around
phenolic switch wafers (some people claim the chemical can saturate the
wafers and make them swell in time). Just apply a drop to each contact
and "work" the switch as you go. Hardly any "contact cleaner" you can
buy -- most especially the Radio Shack variety -- can match the
efficiency of DeOxit.
I also use DeOxit to clean tube sockets and pins. Go to a drug store's
toothpaste section and buy some interdental brushes. They're tiny little
brushes that come in packs of five or six. They're perfect for tube
socket cleaning. Just remove the tube, douse the brush in DeOxit and
run it into each socket pin -- like cleaning a gun barrel. You can wipe
the tube pins with a paper towel moistened with DeOxit, too. This
simple, 20-minute operation cured a couple of intermittent and noise
problems on my HQ-170AC.
Anyway, best of luck and keep us posted!
73,
Craig Roberts
W3CRR
.
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