Electronics > Repair
Repair : HP 3245A precision DC/AC source
alanambrose:
>>> Alan, he was referring to my post with that suggestion. What I meant is to use average of few readings already after settle time elapsed, with few first readings disregarded. I often see that voltages measured are not accurate to last bits if just first reading is taken, even NPLC 100. Sounds fishy, but it could play a bit at very last digits of accuracy.
Ahhhhh - I didn't see that text underneath the graph, now I understand.
OK will add a count of readings to ignore at the beginning and also a count of readings to average.
93% headroom - very nice - will try a recal on mine.
Alan
klaus11:
TiN, it would be feasible and safe to make a board of Amplification (option 002). For units without 002
alanambrose:
>>> TiN, it would be feasible and safe to make a board of Amplification (option 002). For units without 002
That's interesting - mine doesn't have the 002 channel. Care to explain further?
>>> I still cannot get 10.00000 reading from 3458A
Well a bit ambitious given the specs of the 3245A - but 'nuts' is in our name right :)
A.
TiN:
Alan, I'm sure your read my article, aren't you? :) I cover this right in the intro.
You have 3245-001 (option 001, which is two identical +/-10V 0.1A channels), while I have 3245-002 (option 002, on which instead of board B there is x10 power amplifier board, to boost +/-10V to +/-100V, purely analog).
alanambrose:
Ah yes, I know you have 100V option and I have 2x10V.
I was interested in what Klaus had in mind re a non-HP 002 option. It would need to go in a separate box for me as there's little room once you have 2x10V boards installed. Easy enough (well maybe) to build the option from the schematic, but maybe it can be improved / extended.
On another subject ... we have a sense of the 3458A and 3245A tempcos now. Well, in both cases, the fan is a simple always-on low-tech thing. So one easy way to reduce drift would be to run the fan from a PID controller. I think to do this well, we might characterise the main components responsible for the tempco a little and then site the sensor(s) near those. What do you think?
A.
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