Faulty digital micrometer

[Bill DawesParticipant @billdawes]

I have a digital micrometer, Machine DRO brand bought about 5-6 years ago. Hadn't used it for a while and when I came to use it the other day I could not set it to zero whenever it was wound back shut, measurements are all over the place. for instance wound it out about 1/4" and it read 2" plus.

Several emails to Machine DRO resulted in them saying they could not help.

Battery volts was ok but put new battery in anyway which was a silver oxide type.

Suspect dirty contacts somewhere inside, anyone had this problem and did you sort it. Seems like nothing to lose by trying to take it apart and see what gives, otherwise throw it away and buy another one.

Bill D.

[Bill DawesParticipant @billdawes]

[Grindstone CowboyParticipant @grindstonecowboy]

Not sure if it may help in this case, but I've had digital calipers in the past where the old battery had to be removed for about 24 hours before putting in a fresh one, otherwise readings and display were all over the place. Presumably some tiny residual charge was enough to retain garbled info.

Rob

[bernard towersParticipant @bernardtowers37738]

Have you tried removing the batt and shorting pos and neg terminals for a while to see of that will reset it?

[Bill DawesParticipant @billdawes]

Removing battery was a suggestion from Machine DRO which I tried although not a full 24 hours so will give that another go. Will also try shorting across the terminals, presumably this fully drains any residual voltage?

I did have a similar thing with a DRO (after market DIY fitted) on my milling machine but that was easy to get to, a wipe over cured it. My mic is stored in a drawer in its case so should not suffer from a similar problem.

Bill D.

[Bill DawesParticipant @billdawes]

Tried taking battery out and shorting terminals inside mic, put back together, zeroed, wound in and out and said well done Bernard, that's done it, zero every time I wound it back in. Alas switched it of and tried again but back to random figures.

Taken battery out and will leave for a good 24 hours.

Bill D.

[Bill DawesParticipant @billdawes]

Still nothing doing with my mic, left battery out for a day but numbers still all over the place so sounds like a dirty contact somewhere.

Found a Neil Wyatt post in 2014 where he had stripped one down referred to the zebra strip.

Plucking up courage to take mine apart, nothing to lose I suppose, it's no good as it is.

Bill D.

[Howard LewisParticipant @howardlewis46836]

Try cleaning the contacts with a fibreglass brush?

Howard

[KhefinParticipant @khefin]

Morning!

I have had similar problems with my digital micrometer in the past, and with several digital callipers. In the end I found that the battery and terminals needed a thorough cleaning with meths or lighter fuel, as there was some oily substance that had contaminated them. It seems to reoccur every so often. I think it's leeching from the silicone buttons.

I often clean the keypad internals of remote controls of a similar oily substance when they start malfunctioning. So I would try that first and if it persists, clean the contacts of the keypad before completely dismantling the micrometer.

The Zebra strip problems usually show as faint or partial LCD display.

Good luck

Kevin

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