[volt-nuts] Serious problems fluke 731A, 720 and solartron

[Fred Schneider]

The voltage collapses. I have to measure how much but not just a few uV. More like 200 mV if I remember it right. I know it is a resitive divider but the influence on each other is getting worse if it is on 24/7,  another sign something is wrong. The 1V influences akso the 10 V so you keep it adjusting. If i set 10 V correct and then the 1 V's the 10 V is off again.


The 845 AB had its nicads removed and they placed a big zener instead. The most important thing, I made a regulated and good filtered powersupply. I placed the pcb for that in the space the nicds were mounted. 
I also have a HP frequency standard that had a batterybox. But they were dead and i did not needed that so now i build a trimble thunderbolt into that space and used the 100 KHz output of the HP for the 10 MHz. That is the advantage of having gear with a battery option ;-)

I can think i can fix the solartron Problem if I can find a service manual. But now I can not even check the powersupply voltages because I do not know them. Filtercaps are good.

Fred


>> 
> 
> Fred,
> 
> What happens to the 10 volt position of the Fluke 731 when you attach a 10 MegOhm input Voltmeter ?
> 
> I am sure you know that the 1 volt positions are just resistive dividers and any loading of any kind will drop their value.
> 
> Also, could you give details on what modifications you made to the 845AB ?
> 
> thanks,
> 
> Bill....WB6BNQ
> 
> 
> 
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