[Amps] SB-220 amp help

[Gudguyham at aol.com]

GM guys, since we are beating the hell out of the Heathkit amplifier these  
past few days, I want to offer some help to you who are new to the amp.   
Here is an occasional problem that comes up that can frustrate you.  Does  
your sensitivity meter not work right?  Does it only give you a reading a  one 
point is its rotation?  Then when it does, the meter slams against the  
pin?  SO you say oops, my sensitivity pot is bad, and you replace it and as  
soon as you put power through your new pot it goes south again?  The  problem 
is leakage in the 1N191 detector diode. You need to change the  diode or 
else you will burn up any number of pots you replace.  The 1N191  is not made 
anymore and it looks like 1 1N60 is a good replacement.  This  tip might save 
you a lot of aggravation.  I am assuming what happens is  that the diode 
leaks RF and it burns the pot as I have dissected several pots  and found the 
same "burn" on all that were bad. Happy  motoring.