Hi Ed, Thanks for your time and your great suggestion. At this point, I think that the suggestion to use the Tempco thermoswitch will be the best way to preserve the original design of the inner oven and easiest to reverse should an exact replacement Princo thermoswitch become available in the future.
Best Regards, Russ -----Original Message----- From: Ed Palmer <[EMAIL PROTECTED]> To: [email protected] Sent: Tue, 19 Aug 2008 4:00 pm Subject: Re: [time-nuts] Restoring GR 1120-AB Frequency Standard - Need assist... Russ, I don't know what your requirements are for current capacity or mounting, but you might be able to find a simple crystal oven that you could rob the thermoswitch from. There are various ones on ebay that are 75 C. With luck, you might find an adjustable one that you could tweak to 78 C. Another thought is to replace the switch with a simple solid-state circuit. Since you'd be replacing an on-off switch, something like a thermistor + comparator would be appropriate Even if you were trying to do a 'return to original state' restoration, at least it would allow you to have a working system while you wait for something better to show up. Ed > Date: Tue, 19 Aug 2008 11:46:56 -0400 > From: [EMAIL PROTECTED] > Subject: [time-nuts] Restoring GR 1120-AB Frequency Standard - Need > assist... > To: [email protected] > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="us-ascii"; format=flowed > > > I am in the last stage of restoring a 1964 General Radio Frequency > Standard Model 1120-AB. > > I'm having trouble getting the inner oven to work propoerly and the > problem has been traced to a defective thermostat in the inner oven. > In checking, the thermostat is a thermoswitch manufactured by Princo > and is no longer available. > > My options appear to be: > > 1. locate a working GR Standard Frequency Oscillator (1113-A) and > replace the entire chassis. > > 2. locate a non-working GR Frequency Oscillator and part it out as > needed > > 3. find a suitable replacement for the original thermoswitch (78 C - > closes circuit when temperature is reached) > > > I was wondering if anyone on this list has any sources or leads for #1 > and #2 and any opinions on a source for #3. > > Thanks > Russ WA3FRP > _______________________________________________ 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.
