[R-390] R-390-A problem

[Steve Toth]

FWIW: Encountered  a couple of similar problems recently restoring an HQ-129X:
1.) Warbling on the BFO.  Went away when I pushed sideways on the converter tube (6K8).  Turned out the converter filament ground wire looped through the ground lug and touched the ground lug on the tube socket but was never soldered (apparently at the factory as it was completely clean) resulting in constant fluctuating filament connection.  Soldered it and resolved the issue.
2.) Loud static/popping/crashing when adjusting one RF coil during alignment.  Duplicated by pushing on the coil form.  Two solder connections on the coil form had gone bad after 60 years - resoldered the connections and problem resolved.
 
The four best troubleshooting tools available to you:  your brain, your nose, your eyes, your ears. My two cents.








-- Steve 
"Think Quickly, Speak Slowly, Work Diligently, Live Simply"

--- On Wed, 2/2/11, wli <wli98122 at yahoo.com> wrote:


From: wli <wli98122 at yahoo.com>
Subject: Re: [R-390] R-390-A problem
To: youngbob53 at msn.com
Cc: "R390A" <r-390 at mailman.qth.net>
Date: Wednesday, February 2, 2011, 8:24 AM


I, too, was frustrated when my audio volume suddenly faded after being in operation for 5-30 minutes. I got led down the *garden path* thinking that being powered up had something to do with the cause. Not so. There a poor electro-mechanical connection in the phono plug. 

When the SAME phenomenon occurred a decade later: it was a loose screw on the speaker terminal strip causing an intermittent !

W. Li


      
______________________________________________________________
R-390 mailing list
Home: http://mailman.qth.net/mailman/listinfo/r-390
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:R-390 at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html