3 questions

[James Cook]

 I'm restoring a SB220 amp and have a couple of questions that someone might be able to help with.
The plate current meter was initially working fine but over the course of the last year it has become
intermittent. It acts as if current doesn't have a reliable path through the meter coil.
I recall reading an article on that problem and it was stated that dis-similar metals were used inside
the meter leading to this eventual problem.  A suggested cure was to use conductive paint across the dis-similar metal junctions.  What I am wondering is how to get inside the meter to access those junctions.  Any tips 
would be appreciated because I sure dont want to damage the meter trying to get it apart.  Does the 
front plastic case just pop off ?  How does one get the meter face off to get behind it ?  
Any hints welcomed so I dont do any damage to my antique !
 
Also, does anyone know of a source for the Heathkit green paint? The case is in need of a fresh coat.
 
I did all the Harbach mods and the amp works just great .... new caps and all. 
Only dis-like is the fan noise ... I installed the Harbach fan motor and fan blade but it is no
less noisy than the original fan.  Might consider a 2 speed fan speed switch for when I'm loafing the
amp. 
 
The manual says to run CW at 500ma plate current .... I wonder if that is only because of the 
1KW dc input power limit of that era  or because the plate XFMR shouldn't do more....
I have been occassionally running mine at 700ma plate current (700+ watts output) and wonder if I
am overworking the plate XFMR ?  That's on the CW/Tune plate voltage setting of course....
I know better than to op CW in the SSB position.   Any ideas on the 700ma Ip? 
 
OK....thanks for any thoughts .......love the old stuff I can work on !   Jim  N5KY   
 
 
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