I've been debugging a FTS 4050 with the 5000M module. It looks like the problem is the FTS 1200-100 OCXO. It seems to have aged to the point that it is very low in frequency. (Chuck Harris reported a similar situation a long time ago.) I have it out of the 5000M and determined that I need to give it +8.8V on the control to get it within 50uHz of 5 MHz. The power draw after a short warm up is < 2.5W (on this hot day); it looks like the oven is behaving. Has anyone figured out how to adjust the nominal frequency of an FTS 1200 -100 to recover the EFC range? Also, anyone have a schematic for any model of the FTS 1200? Thanks, -christopher 73 de AI6KG

Christopher, my 4060 has been locking exactly 0.5 Hz off of the correct frequency. The 1000B has had a contact problem on the edge connector. Over the years, an insulating black layer had built up between the solder and the gold plating of the contacts. I had to re-solder each of them carefully twice to get it working reliably. Regards, Adrian Christopher Hoover schrieb: > I've been debugging a FTS 4050 with the 5000M module. > > It looks like the problem is the FTS 1200-100 OCXO. It seems to have aged > to the point that it is very low in frequency. (Chuck Harris reported a > similar situation a long time ago.) > > I have it out of the 5000M and determined that I need to give it +8.8V on > the control to get it within 50uHz of 5 MHz. > > The power draw after a short warm up is < 2.5W (on this hot day); it looks > like the oven is behaving. > > Has anyone figured out how to adjust the nominal frequency of an FTS 1200 > -100 to recover the EFC range? > > Also, anyone have a schematic for any model of the FTS 1200? > > Thanks, > -christopher > 73 de AI6KG > _______________________________________________ > 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. >

Hi Adrian, Thank you for your reply. Is this board deep inside the OCXO? I haven't ventured past the output amplifier board stack at the "front." The styrofoam insulation seems pretty fragile from age and heat. -christopher 73 de AI6KG On Mon, Sep 19, 2016 at 12:28 PM, Adrian <rfnuts@arcor.de> wrote: > Christopher, > > my 4060 has been locking exactly 0.5 Hz off of the correct frequency. > The 1000B has had a contact problem on the edge connector. > Over the years, an insulating black layer had built up between the > solder and the gold plating of the contacts. > I had to re-solder each of them carefully twice to get it working reliably. > > Regards, > Adrian > > Christopher Hoover schrieb: > > I've been debugging a FTS 4050 with the 5000M module. > > > > It looks like the problem is the FTS 1200-100 OCXO. It seems to have > aged > > to the point that it is very low in frequency. (Chuck Harris reported a > > similar situation a long time ago.) > > > > I have it out of the 5000M and determined that I need to give it +8.8V on > > the control to get it within 50uHz of 5 MHz. > > > > The power draw after a short warm up is < 2.5W (on this hot day); it > looks > > like the oven is behaving. > > > > Has anyone figured out how to adjust the nominal frequency of an FTS > 1200 > > -100 to recover the EFC range? > > > > Also, anyone have a schematic for any model of the FTS 1200? > > > > Thanks, > > -christopher > > 73 de AI6KG > > _______________________________________________ > > 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. >