Datron 1081 Meter and Negative Ohms

[MaxFrister]

I have  a Datron 1081 7-½ digit multimeter that I restored recently.  Mostly it seems to be working great.  However….

If I let it sit with the power off for a week or so and then turn it on and place it into resistance mode, it often shows negative ohms (e.g., -247,334).  Nothing I do from the front panel seems to reset it.  DC and AC voltage seem to work okay.  Turning it off and back on always clears the problem.

I’ve dealt with intermittent failures before but the one trial per week makes this a challenge.  The meter has been completely re-cap’d and a new battery installed (amongst other things).

I’m looking for suggestions as to what to try next...

[maginnovision]

Have you done the calibration on the ohms board? I'm pretty certain it's the same as 107x(possibly 106x). If you'd like I can check tomorrow, but that's where I'd start. Actually it doesn't matter since the service manual is available. Also pages 26, 27, and 28 have a lot more info. Just start at the relay and work your way through.