SB200 - general questions

[Tom Buchanan]

I have a SB-200 I recently refurbished with the Harbach mods and several new
parts.  It has new caps and 2450 HV with idling plate current of 60 ma which
is a little low.    I get full output on CW (500w) & SSB (600-700w) on 20 to
80 meters.  Low output on 10 meters SSB of 250w max.

 

What is the best 572B replacement tube to use?  Would tweaking the 10 meter
coil or checking the parasitic resistors help the low output on 10 meters?

 

A 10 uH RF choke attaches to the lugs on terminal strip "M" on the back of
the chassis under the final output tubes.  It is supposed to have a 2 lug
terminal strip, but someone installed a 4 lug in the past.  There are little
coils of small wires to connect lugs 1 & 3 and 2 & 4.  It looks like a
jumper wire would do the same thing.  Anyone know what the purpose of the
coils would be? I have a picture of the amp with the jumper wires at
http://scrtc.com/~tlbuch/Vintage%20Heathkit%20Ham%20Radio%20Equipment.html

 

 

Thanks & 73,

 

Tom

KG4KGY

 

 

 

 

 

 


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