Manual/schematic for HP 6186C

[xantia_99]

Hi

Now I  search for a manual with schematics for the HP 6186c current source 0-100 mA and 0-300 Volt. Most of the current part works but the voltage limit function  have severe problem.The transistors looks OK after some changes

As I have seen here before it exist quite a good manual but without schematic and one version with a very bad schematic.

I look forward to hear if someone have any news in this area.

Best regards


Stephan

[duak]

Here is a scan of a manual with schematic: https://neurophysics.ucsd.edu/Manuals/Hewlett%20Packard/Current%20Source%20Model%206186c.pdf

[Ordinaryman1971]

I've had a problem on mine when the compliance voltage was stuck at about 60V with just a little wiggle but no way to adjust it.
I've traced the problem to one of the TO-3 transistors.... 2SC1576, they are hand picked for this application and very hard to find.
I'm still waiting for replacement so the current source is just sitting on the side of my desk....
Just wanted to add, it's beautiful design and show me another one with 300V compliance voltage that would be that affordable.

[xantia_99]

I had to change two 40327 voltage limit current source breakdown and now the current looks okay. But my new yellow light diode in the old limit light turns off at 100 volt. never get higher than that. Looking at around at all zenerdiodes and stabistors just now. 
But the schematics make me crazy.
Regards
Stephan

[xantia_99]

Hi
After some work I found several zener diodes out of order, shortcut, lost value. So in the end I found the lost 230 volt. Now it's up and running again, some small adjustment left,  as calibrate and clean up all the temporary solutions.
 
Best Regards
Stephan