[time-nuts] HP 106B quartz frequency standard...the story so far

J. Forster jfor at quik.com
Sat Aug 8 15:19:45 UTC 2009


I don't have the prints, but suspect there is not an IC opamp in the
regulator. The unit is too old. IMO, it's more likely to be built out of
discrete parts. You might therefore look for a leaky capacitor also.

-John

===========


> The 2N1701 is a general purpose transistor rated at 60V,  2.5A.   Problem
> is it is in a TO-8 package.  You probably won't find an exact replacement
> as this package is rather rare.  You should be able work in a TO-220 or
> smaller packaged device.  NTE lists a cross reference for the device.
> Watch the pinouts.  Canned devices usually go E-B-C.  TO220's usually go
> E-C-B.
>
> A 1V drop across the regulator pass transistor could be due to a shorted
> pass transistor,  but is on the high end of what you would expect to see
> with this kind of fault.  My bet is something else in the regulator.  If
> there is an op amp (usually a 741) acting as the error amp,  I would start
> looking there.  This is a very common part to see fail in this application
> in equipment of this vintage.
>
> ----------------------------------------
>
>
> _________________________________________________________________
> Get free photo software from Windows Live
> http://www.windowslive.com/online/photos?ocid=PID23393::T:WLMTAGL:ON:WL:en-US:SI_PH_software:082009
> _______________________________________________
> 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