[Heath] SB-200 weirdness

[Glen Zook]

Check the tube sockets for corrosion or overheating.  Also, check the tube pins for overheating.  You might have to resolder the tube pins.

Clean the socket connections, tighten them, and also resolder the wires to the tube sockets.

Glen, K9STH

Website:  http://k9sth.com


--- On Sun, 1/23/11, Kenneth G. Gordon <kgordon2006 at frontier.com> wrote:

I am hoping that someone else here, besides me, has had the following problem with their SB-200 and can tell me what, if any, solution they came up with:
 
My SB-200 has had this problem since the day I bought it from a friend: idle current appears to be 10 mA instead of the correct 50 mA....most of the time.
 
There will be times when the idle current suddenly appears to be correct (50 mA), staying that way for, perhaps, a day, then dropping back down to 10 mA.
 
During the times when the idle current is correct, input plate current at resonance, and power output rise to what I consider to be correct values, and grid current drops.
 
During those times when the idle current is low, I have difficulty keeping grid current below 100 mA (I prefer it to be about 50 mA), and both plate current and power output are low, plate current being lower than 400 mA at those times.
 
I have examined every component several times, subsituting a good component where and when I thought I had a "marginal" one, but nothing seems to help.
 
I have also substituted final amp tubes, and the same thing occurs with all of those I have tried.
 
It seems to me that I am overlooking something, but I have, so far, not discovered what that might be.
 
Is there any help out there for this?
 
I am about to dismantle the entire thing and rebuild it from scratch in hopes that I will somehow find the intermittant part...if there is one.