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

[Adrian]

Jim,

shit just happens ;-)

Thanks for the manual.
Apparently the +18 V supply on the outer oven controller A1A4 is faulty.
The 17.4 volts are just 18 V - Vbe.
Read 4-42 and check the circuit on fig. 5-8.
The series regulating transistor is Q9.
Check voltages on Q7, Q9 first.

Adrian

Jim Palfreyman schrieb:
> As has been pointed out, my post intended for the group didn't reach
> it. It is answering the question as to WHY I fiddled with the oven
> temperature. Here it is:
>
> --------------------
>
> Well I can give you an answer - but it doesn't change anything :-)
>
> Oh great flying spaghetti monster, forgive me for I have sinned...
>
> The external frequency adjust mechanism had been removed and I
> couldn't find how to adjust the frequency. There were just two screws
> on the oven, one shallow and one deep in the oven. Since the 10811
> frequency adjust is a screw deep in the oven I assumed that was it. A
> turn of the screw confirmed it - I changed it and then the frequency
> changed. So I tried to adjust it to get 5MHz. But I couldn't do it. I
> also didn't have the manual at this stage.
>
> When I did find the frequency adjust screw (very obvious on the front
> of the unit - blush) I realised what I'd adjusted was the inner oven
> temperature.
>
> F*&%&$^ #$%^ I think came out of my mouth at this point.
>
> So that's the story how. Now I want to fix it.
>
> ---------------------
>
> P.S. Thank to Bill who phoned me and pointed me to the inner oven. More to come.
>
> Jim
>
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