[time-nuts] HP10544a Technical Info needed

Dr Bruce Griffiths bruce.griffiths at xtra.co.nz
Fri Feb 2 23:01:14 EST 2007


Gerald Molenkamp wrote:
> Hi Howard,
>
> Please find attached a schematic of the 10544, hope it helps in anyway.
>
> Regards
>
>
>
> Gerald
>
Gerald

The connection of the 10K oven monitor resistor R12 in the schematic is 
incorrect.
In this position only the very small deviations in the oven supply 
voltage due to its finite output impedance will be seen as Q4 turns on 
and off.
The resistor should surely be connected to the junction of the 
darlington (Q4) emitter and the oven heater winding resistor??
The datasheet clearly states that the duty cycle of the oven monitor 
varies, as is seen with working 10544As.

Bruce



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