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

[Bruce Griffiths]

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