[time-nuts] HP/Agilent 5065A Rubidium Vapour frequency standard problem - fixed

[Adrian]

Roy,

check this:
http://www.hparchive.com/Manuals/HP-10811AB-Manual.pdf

Btw. you don't happen to have a spare green pilot lamp lens, do you?
That's what my 5065A is missing

Regards,
Adrian


Roy Phillips schrieb:
> 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" <Jim.Palfreyman at team.telstra.com>
> To: "Discussion of precise time and frequency measurement" 
> <time-nuts at febo.com>
> 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: service at frequencystandards.com 
>> [mailto:service at frequencystandards.com]
>> Sent: Friday, 9 May 2008 4:00 AM
>> To: time-nuts at febo.com
>> 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 -- time-nuts at 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 at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>