[Hammarlund] Re Hammarlund re Caps

[Mark Johnson]

Rick, sorry to hear your having problems.

It is possible that one of the cap's you replaced may not be making a good 
connection hence the crackling noise. Try looking very carefully at your 
soldered connections. Is it possible you made a mistake when replacing the 
cap's and installed one to an incorrect terminal or is it possible you may 
have a solder blob bridging two connection points?

Some are of the opinion that a simple clip and tack is acceptable when 
replacing components. That can practice can cause intermittent problems down 
the road. I always fully remove the old lead, using solder wick and 
patience; insures a strong connection.

My recommendation would be to not change out any further parts until you 
isolate your noise problem and the BFO problem. It's possible you could make 
things worse.

A good starting point would be to measure the voltages in the radio and 
compare to the voltages specified in the manual. I have not been into 
Hammarlund rig for some time so I don't recall if the manful has a full 
circuit description or not. If so, take some time to read how the BFO 
circuit is supposed to work and check voltages and if you have a scope, 
check the output.

Personally, and I know this is a hobby Hot Spot topic, I never change out 
cap's in mass. I think the practice is suspect and can cause more problems 
than it solves. If a rig has a bad cap, out she goes as a normal course of 
action during the repair, but blindly changing them out, not for me. Of 
course, if a cap can short and possibly take out an expensive mechanical 
filter - different story.

Hope you find the problem Rick.

Mark V Johnson VE3DJU/VE3DDI
----- Original Message ----- 
From: "Rick Gouge" <rickgouge at shaw.ca>
To: <Hammarlund at mailman.qth.net>
Sent: Monday, December 21, 2009 5:08 PM
Subject: [Hammarlund] Re Hammarlund re Caps


>I would like to thank everyone for there help on the HQ129X. I went ahead 
>and recap the receiver with the caps that i had in stock. First i recap the 
>powersupply and tried the receiver to see how much it had improve. the hum 
>was gone and i had half decent audio and the BFO was working as well. I let 
>the receiver run for about half an hour< Then the BFO stop working and the 
>Audio started to go crappy. I knew then i had to finish the job of 
>recapping, which i did this morning. then i tried the receiver again. Still 
>no BFO. So i started looking around for more caps and check a few resistors 
>around the 6SN7 tube, I replace the 360ohm 1 watt resistor with a 2 watt. 
>which is all i  have right now.  I found more caps in a can on the 
>underside of the 6sj7 tube which fix the BFO. I have been lisening to 20 
>meters now for about 45 minutes and i am getting loud crackle noise once in 
>awhile then it clears up for awhile then the crackle comes back again. To 
>me it sounds like a cap breakin
> g down in the audio section but i replace them all. The only caps that i 
> did not replace where the ones that look like dominos. Maybe thats my 
> problem?  Rick VE7RiK
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