Hi Jim, My thermoswitch was manufactured by Princo, a company that is still in business with headquarters in the Philadelphia area.
I've googled "Princo" for the past couple of years, spoken with folks at Princo, and have a search setup in eBay. Nothing has turned up yet. I've decided to move on since I'd like to complete the restoration of the GR Standard. I purchased a Fenwal thermoswitch that comes closest to the sensitivity of the original thermoswitch. If a 78C Princo thermoswitch becomes available in the future, I'll be able to reverse the modifications that I am currently making to the inner oven. Thanks to everyone on the list for their advice and assistance. Russ WA3FRP -----Original Message----- From: Jim Hall <[EMAIL PROTECTED]> To: Discussion of precise time and frequency measurement <[email protected]> Sent: Wed, 3 Sep 2008 10:06 pm Subject: Re: [time-nuts] Description - GR 1120-AB Frequency Standard Russ, Sorry but the only thermoswitches he has or knows about are for 60 or 70 degrees C units he has. I think he got his switches from GR crystal ovens used for BC transmitters. I imagine their requirements were less stringent than the "standards lab" standard you are rebuilding but then again you never know. Most of the thermoswitches he has were manufactured by "Precision" or at least that was written on each of them. Another thermoswitch was manufactured by "H inside a diamond, B inside a diamond". I think both the GR thermoswitches were manufactured by Precision. I wonder if you could search on eBay or other sites for that name if that is who manufactured yours. Probably a long shot but just wondering. Jim -------------------------------------------------- From: <[EMAIL PROTECTED]> Sent: Wednesday, September 03, 2008 7:55 PM To: <[email protected]> Subject: Re: [time-nuts] Description - GR 1120-AB Frequency Standard > Jim, > > Thanks for following up on this. The thermoswitch that I'm looking for > closes on reaching a trip temperature of 78C. The original unit was > made by Princo. I wonder if your friend could tell me if he has any > leads on a 78C thermoswitch. > > Thanks again, > > Russ > > > > > > > > -----Original Message----- > From: Jim Hall <[EMAIL PROTECTED]> > To: [email protected] > Sent: Wed, 3 Sep 2008 8:04 pm > Subject: [time-nuts] Description - GR 1120-AB Frequency Standard > > > > Today I visited a friend who collects all sorts of old electronics and > asked him > about mercury thermometer sensors. Turns out he had several from > various GR > pieces of equipment. Some are in a straight shape with "trip" > temperatures of > 50 or 60 degrees C. One is at a 90 degree angle with a 60 degree C > trip point. > I'm sure it is a very long shot but I wondered if any of these might > work for > the frequency standard you are rebuilding. > > Most of the above temperature sensors were built by "Precision". I > have the > part numbers. > > What do you think? Does it sound like any of these could be > replacements for > your unit? > > Regards, > > Jim > _______________________________________________ > 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. _______________________________________________ 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.
