SB-200???

[Guy G. Giacopuzzi]

Some things to think about...there's a ton of upgrades and discussion 
regarding the 200'...and I'm no expert....I just went thru one of my 
200's putting in most of Norgard's and Measures' mods for parasitic 
suppression....the 33 ohm grid resistors need to be very close in value 
to each other; Norgard recommends upping their power rating...I 
don't....I like them right at one watt so it can act as a fuse...but you 
need to review what's out there on the mods....try
http://www.westlawn.net/sk/sb200.html, to start, then 
http://www.westlawn.net/sk/ampnotes/ampnotes.html, and finally, 
http://www.somis.org.

Remember to put in the diodes to protect the meter...the grid circuit 
resistor is famous for opening and burning up the meter, and the meter's 
are essentially irreplaceable...Wish I could answer more of your 
questions, but I don't know all the answers....You need to study, study, 
study the above sites...

Guy,
WA6OQQ

Paul Kraemer wrote:
> Working on a SB-200 for a friend (really)
> I only have the download copy of the manual and note the following 
> discrepencies:
> The grid resistors are 22 ohm 1w instead of 33 ohm 1 watt. One of them 
> appears original, one was changed
> The grid choke rfc2 looks "funny" to me. Too new and a 3 pi style. 
> Measures 2.5milli henry not 28 micro henry
> There is no 33 ohm 1 watt in the antenna relay line and doesn't appear 
> there ever was
> There are a new matched pair RF Parts 572-B installed but I am taking 
> this carefully repairing the obvious first, like the HV meter resistor 
> already replaced once before and open alc bias resistor. The filter 
> caps all esr test perfectly ---surprise---but I'll be cautious with a 
> variac first and no tubes.
> Questions:
> Was there a early or late version for the 22 ohm 33 ohm grid resistor?
> Is the bias provided by the 33 ohm in the relay coil circuit beneficial?
> Is the choke in the grid bias critical? If it is then I am looking for 
> a 28 micro henry rfc
> Thanks in advance for your helpful suggestions
> Paul K0UYA
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