Help needed SB-401

Ed Richards k6uuz at JUNO.COM
Mon Aug 6 08:27:06 EDT 2001

Hi, Guys;

I am working on a SB-401 in which the relay (RL-1) won't pull in. I made
the usual resistance and voltage measurements. Aside from B+ being a
little low (+230 instead of +255), all is ok. I measured the relay
resistance at ~4800 ohms and the current at 10 ma. It will not pull in at
10 ma. Should it? I would like to know the spec's on pull-in current. It
is Heathkit p/n 69-40 and P&B p/n MH80574-1. I would also like to know
what the plate current for the tube is with zero bias. it is  pins 5, 6,
& 7 of a 6D10. Thank you.

Ed Richards

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