Old Mitutoyo digimatic indicator power supply

Call this guy and have him give you the direct dial number for their repair facility. I had it around a while back when I was fixing a digital Heigth Gage that isn't made any longr.

Art Rivera Precise Industrial, Inc.

I had the same question once from an mystery auction item. I used my lab power supply to find that +5 VDC worked, with + on the center and - on the outside. Unfortunately in my case the display worked, but the indicator itself was broken and didn't function.

Someone on eBay has a very similar one for sale:

I think that Richard is probably right, but you could also pull the back off the indicator and see if it has an old NiCd battery pack inside. If so, you could trace it to the charger plug and guess voltage/polarity.

I've used something similar in the past and it had an LED display.

You could ask The Horse:

--Winston