If it's an older germanium PNP pass transistor then yes, rest assured, it is leaky and needs to be replaced with a modern silicon part. Germanium power transistors don't age well.
-- john, KE5FX > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on > Behalf Of WB6BNQ > Sent: Saturday, August 08, 2009 5:07 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] HP 106B quartz frequency standard...the story > so far > > > > > And one more request, please measure and tell me what the values are for > the base of the pass element and any driver transistor connections. > > Also, it may be that the power supply is really a current source for > charging the batteries. The power supply and the instrument may need > the batteries to work correctly. Hp was famous for this type of circuit > topology. > > Bill....WB6BNQ > > Hi Jim, > > YES, please email me the schematics. > > thank you > > Bill....WB6BNQ > wb6...@cox.net > > Jim Palfreyman wrote: > > > OK folks, I've rechecked the voltages and here's the details. > > > > Firstly, changing the oven temperature screw was a mistake. Read a > > previous thread to see why I did it. It was logical given my > > experience with 10811 ovens. I've owned up to it and begged > > forgiveness from the great Flying Spaghetti Monster. It never answered > > so it must have made me do it. Please drop that now. :-) > > > > When I first powered the unit up it had bad and leaking NiCd batteries > > and made a horrible sound. I removed those and I presume something was > > damaged. > > > > The "input" voltage to the 2N1701 is normal (according to the front > > panel meter) and is close to 26V. The "output" voltage is 25V and not > > 18V as the manual says. I have the manual now and anyone (with more > > experience than me on old fashioned power supplies) who wants to > > comment I am happy to email the circuit diagram and eagerly await > > comment!!! > > > > Jim > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.