SB-301/SB-401 Functional Repair Guidelines

[Glen Zook]

Loosen and then retighten every machine screw and nut which go through the chassis.  All of the grounds in the units are made through these and they definitely become loose and/or corroded over the years.

I "fix" about 90% of the "screwball" and intermittent problems in "boat anchor" equipment by just doing this one thing.

Glen, K9STH

Website:  http://k9sth.com


--- On Sat, 10/2/10, John H. Klingelhoeffer <wb4lnm at AOL.COM> wrote:

A local club has asked me to look at returning an SB-301 / SB-401 pair to operational condition.  The internal condition looks good and I don't see any mods.
 
From an initial power on, it's quite clear by sound that the receiver needs new electrolytic capacitors.  They appear to be the originals.  That will be my first step with the receiver and the transmitter, too, including several cathode bypass caps.
 
Beyond that, checking the tubes, and a tuneup by the manual, what else should I look to do as far as cleaning and lubrication?  Bandswitch contact cleaning?  LMO maintenance?  Solder joint reheating?  What are problem areas with this pair? 


      

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