[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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