(Old) Hioki 7010 DC Signal Source - Any information? Schematics?

[kblue]

Hello there!

Found this "little" thing and its a bit "off-spec". For example 5.000 V Output is reported as 5.012 +/- V. Tested with different Meters. So far no luck with any useful information. However, i was able to find some pictures with similar looking units with up to 10 VDC output (my one stops at 8.000 V for V-DC and 80.00 mA-DC) at japanese auction sites. Mayhaps someone here has more informations available? It does look like a rather nicely made unit and it would be nice to check some simple meters


Best wishes from germany!

[Overspeed]

Hello

First step is to recap the PCB , all electrolytic Caps shall be changed for fresh one's and PCB inspected for corrosion

Regards
OS

[kblue]

Hello again!

No luck after changing the caps. Most of them also measured completely fine. Guess without schematics or something similar, this will be on hold for a long time. (possible eternity)

Best wishes!

[coromonadalix]

best  would be to measure  each trimpot center wiper  to each side,  note them and on a function try to fiddle with it ?

you need to decipher  on witch function the circuitry work


try to find data  on some of the ic's, some must be switches   ...
upd7514 is the mcu
ad7541 is an 12 bit DAC ??
lm301 = op amp
lf411cn = JFET-input op amp
SN74HC540 =  Octal Buffers and Line Drivers With 3-State
NJU7301D = Analog Switch ICs CMOS Quad SPST               that would be the ones ??
M5218 = Dual Low Noise OpAmp


found that japaneese documentation  on    https://www.hioki.co.jp
and english at https://www.hioki.com/download/30540

[mawyatt]

If all else fails and you decide to risk a pot adjustment to bring the output level in-line, VR2 seems a likely candidate to tweak the output level. Say this because it's a 10 turn pot and would expect any kind of fine tuning the output would rely on a 10 turn pot, and it's near the DAC which would seems logical.

As mentioned above carefully take note of the pot position, so you can return to that position if this doesn't have the proper effect.

Hopefully you'll get a schematic from someone and be able to better understand the circuits and what the various adjustments represent.  Of course you could attempt to trace out the circuits and create your own schematic, that would be what we would attempt before "blindly" attempted any adjustments, but this likely will entail a lot of time and effort.

Anyway, just a guess at what to adjust if you decide to try.

Good luck!!

Best,