DM501 multimeter on extension cable


Kevin Oconnor
 

I have a DM501 that seems to need calibration. Very hard to do plugged into a mainframe.
The DM501 works in the mainframe, albeit with an improper display.
I built an extension cable about 3ft long that carries all of the non-discretionary signals. Other
plugins seem to work fine on the extension cable. But the DM501 will not properly power up on the
extension. From what I can see, the power supply using the LM723 will not work. The pass transistor for
this linear regulator is in the mainframe. I suspect the problem is in the feedback loop with the remote
transistor. Any advice in operating this plugin on an extender would be appreciated.

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