Hi Dave: Do you have a photo?
It's been my experience that older electronic equipment fails because of poor connections rather than bad components. For many examples see: http://www.prc68.com/I/HaT.shtml Have Fun, Brooke Clarke http://www.prc68.com/P/Prod.html Products I make and sell http://www.prc68.com/Alpha.shtml All my web pages listed based on html name http://www.PRC68.com http://www.precisionclock.com http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Web Cam David C. Partridge wrote: > Nuvistor is NOS, and I've tried swapping them. > > Circuit has anode (plate) connected to a 50MHz tuned tank. > > G1 is connected to ground via a 100K resistor, and to the cathode via the > crystal and trimmer cap. > > Cathode connected to ground via a ferrite tunable slug inductor (6-10uH) > close to a similar one also 6-10uH. The second one has 100K in parallel > with 1nF to ground, and 15pF across the inductor. The second one has a > pick off coil of a couple of turns which sends the signal to the countdown > board. > > The full schematic is in the Tektronix 184 manual on BAMA which is in djvu > format. > > Cheers > Dave > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > Behalf Of Bruce Griffiths > Sent: 07 September 2008 23:38 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Ancient OCXO in scope calibrator. > > >> Dave >> >> Need a few more circuit details. >> The crystal current wont be very high unless their are other >> components connected to G1. >> >> Bruce >> >> > The anode G1 capacitance is about 10fF so with 25V rms at the anode, the > crystal current would be around 16uA if the circuit relies on feedback via > the anode to grid 1 capacitance. > This seems to be a little low to be useful. > You could try substituting a newer 7587 there are several currently > available on ebay and elsewhere. > > Bruce > > > _______________________________________________ > time-nuts mailing list -- [email protected] To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
