[Hammarlund] SP-600-jx-6

[wb3fau55 at neo.rr.com]

Gentlemen,  I have a strange AVC problem  in this unit. I suspect a problem in the bias supply,  but I have not measured  any voltages here.  What happens is when you 1st  turn it on,  everything seems to be normal.  Suddenly,  the S meter pegs, with no signal.  You can lower the meter reading and background  noise level with the RF gain.   This occurs on  the lower bands.  UP on 14.8mc,   it seems OK.    Also worth noting,  if you keep the RF gain  low on a startup,  the problem stays away  for a much longer period.  The AVC switch is good.  When the problem is there,  you can pull the bias supply 6AL5 and no change.  So I guess that is my clue- no bias supply and no AVC action?  thanks for input  Russ wb3fau