[ARC5] HP-3200B Accidental Repair

[Robert Eleazer]

Thanks to all those who offered some advice on data on the question of tube equivalents to a 6DZ4/6AF4.  Between that info and consulting the 1965 ARRL Handbook I was able to find some equivalent tubes that were listed in my tube tester's data.  Trouble was, all the 6DZ4/6AF4 tubes I have, both the ones in the HP-3200B and the replacements I purchased, checked bad on the tester.  I put the replacement tubes in anyway.

It still had no output.  I then started the troubleshooting procedure.  B+ was Okay, but there was almost no filament voltage!  The HP-3200B uses DC filament voltage and has an adjustable regulator circuit for it.  I spied an adjustment pot and tried turning it.  Suddenly I had some filament voltage and the unit started operating.  It puts out a good strong signal but needs some calibration.  The calibration on these things with the slide rule tuning seems to be fairly "notional" anyway, but I'll see about getting it closer.

So, thanks again!  And does anybody need an HP-3200B?  

Wayne
WB5WSV           
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