Chuck wrote: One last word of advice...DON'T adjust ANYTHING on the unit until you have figured out where your problem is. If you have a really good standard already then you could use it to check the oscillator with and adjust it but other wise, leave it where it is for now.
Absolutely. Especially don't mess with any of the mechanical adjustments on the A4 harmonic generator that is attached to the CBT. These are aligned to resonate exactly to 9.192 GHz and it would be almost impossible to realign one without using a special waveguide tuning fixture. Only a few of the extrusions are intended for matching the A4 to each individual CBT. If you've already turned some of the knurled screws, nuts, knobs, and hex screws, you may never be able to capture the correct resonant peak, even if you can get the cesium oven to start working. The best remedy to a mis-aligned harmonic generator is to find another one that has not been adjusted and attach it to your CBT, or send it to someone with the correct waveguide fixture. Dave Carlson ----- Original Message ----- From: "Frequency Standards & Services" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]>; "Discussion of precise time and frequency measurement" <[email protected]> Sent: May 26, 2005 2:32 PM Subject: RE: [time-nuts] hp5061A questions Hi George: You have a pretty common problem with used cesium's. The first thing to do would be to look and see if the ion pump current is very high. If it is, the cesium oven will not turn on. Until the cesium oven is on and operating at normal temperature, you cannot get any 2nd harmonic or beam current. The oven should indeed be on all of the time. You will not feel a great deal of heat on the tube though since it is a double walled tube. There isn't a test point that you can measure to tell if the oven is working correctly since it isn't a simple DC voltage that is applied to the heater circuit. It is a bridge circuit that uses the heater, a thermistor and some resistors to balance the tube out at the right temperature. The tube would have to have been handled pretty rough to have damaged the heater element. I wont say it can't happen but isn't likely to be the problem. I am not aware of any web sites that have a manual on them. Perhaps someone else in the group knows of one. I have several "check" procedures that I can send you if you want to e-mail me direct. They are probably more than what we should post on this board. They give you steps to check out the unit and tell if you have a probable bad tube or if there is something else wrong. One last word of advice...DON'T adjust ANYTHING on the unit until you have figured out where your problem is. If you have a really good standard already then you could use it to check the oscillator with and adjust it but other wise, leave it where it is for now. Chuck Norton Frequency Standards & Services 2727 E. Palmer Park, Ste. 100 Colorado Springs, CO. 80909-3032 719-228-0540 voice 719-228-9009 fax -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of george Sent: Thursday, May 26, 2005 10:27 AM To: [email protected] Subject: [time-nuts] hp5061A questions I just got my first Cesium atomic oscillator (hp5061A) please help! I dont have a meter reading for the CS oven and believe the oven is not functioning. The cs oven controler switch is on and set to normal temperature. Shouldn't the CS oven be on all the time like the quartz oven or are there other signals required before the cesium beam oven activates? And shouldn't I be able to feel heat from the Cesium beam case indicating oven operation? I also have no 2nd harmonic or control readings, all other reading seem ok, what frequency would the second harmonic be? I see some test points on a pcb interconnect strip under the bottom cover ie 18 v 18v 18v 25-30v synth control 1mhz 100khz control. are these control, control test points the same as the mult-meter control measurement or are these all seperate control voltages for other functions? All voltage test points are good. I didn't check synth, or control test points fearing that a high impedance vtvm would be required Could someone point me to the supply point for the Cs oven heater voltage or possibly describe the heater element itself? Is it delicate enough that coast to coast shipping could have opened the element? Are there any online documentation for the hp5061 I can use before obtaining a service manual? Also on the cs controler is a pot adjustment labled Mass Spect. What is this adjustment for. Thanks for listening. _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
