[time-nuts] My NTGS50AA failed

Charles Steinmetz csteinmetz at yandex.com
Tue Nov 11 21:08:56 EST 2014

Ignacio wrote:

>I'm not very sure that the DAC is working, I suppose that the unit 
>doesn't measure the DAC output, it reports the DAC commands.  My 
>voltage figures is what LH reports (so the NTGS50AA reports, 
>probably what it is trying to do), but the frequency control pin of 
>the oscillator is stuck at 5.02 V regardless of the supposed 
>(intended) DAC output, it does not move at all.

I'm not sure I understand what you've measured.  I take it you have 
measured the EFC pin on the OCXO, and it reads 5.02v?  Have you also 
determined what the voltage is on the DAC output pin?  (Are they 
connected directly together, or is there a resistor or other 
circuitry between them?)  If they are both at 5.02v, you need to 
disconnect them and see which one is pulling the node to that voltage 
(it could be an internal failure in the OCXO).

Best regards,


More information about the time-nuts mailing list