Jim I have just found a 10811-60111, and I am wondering if you or another member have the complete schematic for the unit - mine has the PC board # 05328-20027, with "fine adjust" pot and C12 &C15 - or is this the normal format. I have not yet power it up and have noted the advice about adjustment.
Thanks Roy ----- Original Message ----- From: "Palfreyman, Jim L" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" <[email protected]> Sent: Sunday, May 11, 2008 1:18 PM Subject: Re: [time-nuts] HP/Agilent 5065A Rubidium Vapour frequency standard problem - fixed > Thanks folks for all your efforts. > > It turns out I was right about the 10811. My replacement 10811 fixed the > fault but as Chuck pointed out I was being to much of a cowboy with the > course adjustment. Instead I tuned the course control of the 10811 to a > reference 5 MHz on the bench and then plugged it all in. This time it > worked and it stayed working well too! I've been calibrating the C field > over the last 12 hours. > > Now of course I'm turning my attention to the 10811. I would like to fix > that! > > With the heater off, the oscillator behaves well with the course > adjustment providing the appropriate control (haven't check the EFC yet at > this temperature). It is of course below 10 MHz. When the heater is > powered it does the right thing (0.5 amp for a few minutes then drops > back). The frequency rises to a bit over 10.0000 MHz. However the course > control no longer has any effect whatsoever. > > I'm guessing there are some components in the oscillator circuit that are > heat damaged after two and a half decades of being in an 82 degree oven. > I'm going to follow through the manual and see what I can find. > > However, if anyone has experienced this pattern before - please let me > know. > > Thanks again for all your help! > > Regards, > > > Jim Palfreyman > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] > Sent: Friday, 9 May 2008 4:00 AM > To: [email protected] > Subject: Re: [time-nuts] HP/Agilent 5065A Rubidium Vapour frequency > standard problem > > You didn't really say in your description but you really need to have the > loop open using the front panel switch before you try to adjust the > oscillator. Unless you are very familiar with how tiny of a turn it takes > to make it too far off to lock, you will have it out of range very > quickly. Open the loop and connect the 5Mhz output to a good frequency > counter, preferably one that is synched to another rubidium, GPS locked > crystal or cesium. Once connected, adjust your crystal coarse adjust for > as close to 5Mhz as possible. If you can't get it below a 0.1 hz error, > you are going to have trouble getting the unit to lock. Make sure you > allow a good warm up time for the crystal in the 5065 before you do any > adjusting. > If you can get the crystal to that small of an error, then close your loop > and watch the control meter setting. Typical is that the meter will move a > small amount but not peg. If it pegs, you have another problem with the > unit. If it moves a small amount and stops, you can then adjust the coarse > or fine and bring the meter back to zero. If you use the coarse adjust, at > this point, you are going to be making VERY tiny adjustments of it. > Let us know what you find from this and we can move you to the next step. > Chuck Norton > > > > > _______________________________________________ > 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.
