Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
Diagnosing and tracking down sliver mica disease in HQ 170




 
The AM Forum
November 20, 2018, 07:26:32 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Diagnosing and tracking down sliver mica disease in HQ 170  (Read 351 times)
0 Members and 1 Guest are viewing this topic.
ns7h
Member

Offline Offline

Posts: 14


« on: October 15, 2018, 03:18:56 PM »

I am asking this community that have experience with the dreaded silver mica disease.  I know the 170 can be affected, but not sure if it affects the 455 KHz, 60 KHz, or other cans in this receiver or that all are prone.  I would be up to replacing or repairing a few, but since it is such a big deal, some guidance on the tracking down part is needed. 

I have experienced some symptoms that appear could be caused by silver mica disease, but not continuously.  The receiver is working very well otherwise, but lacks a re-alignment of the 60KHz IF.  Performance indicates that the alignment may not be warranted.  I use my IC 7600 for comparison and by S meter and audio heard, my HQ 170 is extremely "hot" sensitivity. 

Observations: I do have a suspect tube (V16-6AV6) that has a bad reading on one of three tests done by the tube checker.  Some AVC issues I observe may be caused by this.  Also, some noise occurs sporadically with receiver on standby.  The general noise level on Receive with out an antenna is near zero.  Some episodes of suspect noise increase seem to clear with operation of bandswitch, a symptom acknowledged by Hammarlund at the time but not caused by silver mica disease.

Any additional knowledge on how to diagnose and find a culprit of silver mica disease problem is appreciated.  (Also a source of IF cans). Hi Hi

Bob, NS7H
Logged
WA2SQQ
Contributing
Member
*
Offline Offline

Posts: 585


« Reply #1 on: October 16, 2018, 02:36:05 PM »

This "disease" effected the 40m input coil on my HQ-180. Just a general lack of signal led me to tracing where I was loosing it. Fortunately I had a carcass of another 180 in the garage and was able to swap out the coil and restore operation pretty easily.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.031 seconds with 18 queries.