[time-nuts] HP 10544A with dodgy output?

Bruce Griffiths bruce.griffiths at xtra.co.nz
Fri Jan 15 22:53:02 UTC 2010


Note the early version has a different (tighter) spec for the oscillator 
supply and oven controller supply (10.6V-11.7V) than the later version 
(11V - 13.5V).
The oven supply spec is also different (15V -30V) rather than (20V-30V).

Bruce Griffiths wrote:
> Nick
>
> Nick Foster wrote:
>>> Do you have the serial number of your 10544?
>> 1244A02119
>>
>>
> That appears to be the early, higher phase noise version.
> The later versions have a 15-20 dB lower phase noise floor.
>
> One clue (apart from the serial number prefix) to this is that the 
> CA3045 differential amplifier appears to be used to amplify the 
> oscillator output.
> This will have a higher gain than the later version that used cascode 
> buffer amplifiers with lower gain.
>>> But this would depend on if the CA3045 were used in the oscillator.
>> The CA3045 is only used on the buffer board. The oscillator uses 
>> several TO-5 transistors and a 2N3904.
>>
>>> Is the board shown actually the oscillator board or just the buffer 
>>> board?
>> That's the buffer + AGC board.
>>
>>> Is your OCXO a 10554 or is it a 10544A?
>> Says 10544A on the case.
>>
>> Well, after disassembly, it turns out the problem was a bad solder 
>> joint on the oscillator return wire. Sometimes you just get lucky! 
>> Everything is locked on and working now.
>>
>> Thanks for everyone's help.
>>
>> Nick
>>
> Bruce
>
>
> _______________________________________________
> 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.
>






More information about the Time-nuts_lists.febo.com mailing list