1200Vdc Powersupply - Keithley 240A, goes to 11 !!!

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fperron_kt88
Posts: 72
Joined: Wed Oct 10, 2007 2:19 pm
Location: Montreal

1200Vdc Powersupply - Keithley 240A, goes to 11 !!!

Post by fperron_kt88 »

I found a nice old 240A from Keithley Instruments.

1200Vdc with 3 decade knobs (well, the 100V increment goes to 11!!!!! No joke!!!). This thing seems to be completely floating, with the main output switch labeled -, OFF , +. Output current is limited to 10mA, says the front panel with a nice red pilot light labeled "overload".

The thing powers-up. The 0A2 and 0B2 gas discharge thingies do light up (nice purple glowing tube BTW!).

Output is currently about 300mVdc in all settings though. :-(

Anyone has a manual for this ? It seems like some modifications were done to the unit: one diode is missing (maybe some protection, seemed to be reverse-mounted, silkscreen is calling for a regular, not zener...) and some pretty large power resistors with some brown discoloration all around the pcb mounting points that must have drifted. They look otherwise ok I would say.

Any other info on this unit?

(found this while looking for a scope for the crackling sound in my Major...)

(If that is of any interest I could take some pics...)

Thanks!
fperron_kt88
Posts: 72
Joined: Wed Oct 10, 2007 2:19 pm
Location: Montreal

Re: 1200Vdc Powersupply - Keithley 240A, goes to 11 !!!

Post by fperron_kt88 »

ah ah... feel stupid now... found the manual... http://www.keithley.com/support/keidoc_ ... ype=Manual

:oops:
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