[volt-nuts] Serious problems fluke 731A, 720 and solartron
pa4tim at gmail.com
Tue Oct 4 20:54:38 UTC 2011
A small update:
The 731A turned out to have a dirt problem. There was 200uV voltdrop
over the series resistor between opamp output en output bus. and that
was a dead end so there could be no current running. Only thing in
between was the switchdeck. After ultrasonic cleanig all was rock solid
and adjustments smooth. Set it at the right voltages about 6 hours ago
and normaly it had wandered of about 40uV or more but now it is still at
the same values.
Only thing I am in doubt about: Running on the battery it is perfect. On
230V stable too but not the same value and with a voltage difference if
I switch leads, so there is some stray fields making problems.
The 7061 is complete lineair in the 1V range but still not in the 10V
range. About 20 uV difference between 1 and 10V
Thanks for the advises.
asked a LT1027BH sample (to bad they do not sample the LTZ1000 and I did
not know they are allmost 50 dollars)
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