[R-390] HP410B Intermittent(s)

[Don Reaves]

> get go.  Removing the old gucky solder then liquid flux and heat 
> seemed to give a ok joint.  It was surprising to see that kind of 
> problem inside of an HP instrument.
> 

Not unheard of.  I once found the problem with an HP-200R with intermittent
output to be that a b+ line leading from the power transformer had never
seen a hint of solder.  The wire was wrapped on the transformer solder lug,
and it probably worked OK for a few years, then slowly oxidized.  

A slight variation of the Stockdale technique to restore operation of a
BC-375 worked on the HP-200, before the proper repair was implemented.

http://www.youtube.com/watch?v=TBXmVqcAP6M  (at about 2:30 in this clip)


Don