Starrett 721 Digital Caliper Help

Jay-z

Jay-z

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Recently acquired a Starrett model 721-12 Digital caliper in its original wooden box. It's in very nice shape, doesn't even look like it has ever been used. Put some fresh batteries in it and then found out why. It turns on and some of the functions work but it will not measure anything. So my question is this thing worth fixing? Jay

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my contact Starrett about it You never know what they might do. then if they say it'll be to much $$$ or not something they will look at then maybe try and take it apart your self and see what you can figure out can't hurt after all it already doesnt work...
 
This may or may not be of significance. I had a Browne & Sharp digital caliper years ago; one of the first out. It quit working at one point and when I pulled it apart, the glass Moire screen had come loose (probably due to to dropping). I aligned it and fixed it place and it worked. Now this was an optical scale with LED/photodiode sensor while your Starrett appears to be a capacitive scale but it is possible that a similar thing happened. There have been reports of capacitive scale DRO's not sensing or sensing erratically which have been attributed to pickup misalignment.
I would follow Dracen Knights advice and contact Starrett first. From other posts, it seems that they are very fair about repair costs for their products. If their estimate approaches a new replacement price, then pull it apart. At the very least you will learn something about the technology used; at best you'll have a functioning caliper.
 
Well i did the same as i suggested for a fowler dial caliper and when told they no longer made parts for it. I went ahead and toke it apart and was able to fix it which was important to me as it was my dads. And its one of the nicer ones he had in his tool boxes. Once i had it fixed i became confident in my abilty to fix dial calipers so i then fixed a starrett set as well... i was able to fix several of my dads sets which ment the world to me as its one of his tools that i will get almost daily use out of...

Pretty much what im saying is if the factory wont fix it for a reasonable price then dont be afraid to try it your self whats there to loose it doesnt work as is.. if you do end up trying it yourself please post pics and an little write up... even if it doesnt fix it you never know what one of the other members might know or see and it could lead to them fixing their own or helping you fix yours.
 
Chances are that parts are no longer available and Starrett charges a lot for parts and repairs.
I would guess around $200 or more for parts and labor, if the parts are still available. Even Mitutoyo
discontinues calipers after only a few years. You can buy a nice Mitutoyo for for a little more than repairing this one.

For most digital calipers it's just not worth the money to repair them.
Check the jaws and make sure no light comes through. How much did you pay for it?
 
Receive the pair of calipers with a large amount of other tooling. Just trying to figure out what to do with them.

Jay
 
Iv had some older calipers that get some corrosion on the battery contacts and don't get full voltage it can make them act strange. Also sometimes the battery cover gets loose and causes the same problem. Sometimes you can bend the contact out a little or shim the battery in tighter
 
Take it apart and check the contact points where the rubber/graphite strip contacts the circuit board and the glass. Use an old school pencil eraser to clean the brass contact points and reassemble. Watch out for tiny little brass battery contact pieces falling out. I usually work on them over a white rag.
 
I'd definitely open it up and look for any obvious signs of broken or dirty contacts.
Could also be a mechanical problem. Maybe the gear that engages the rack is damaged or just out of place.
If that's the case, I'd be on the lookout for another one with electrical troubles and use one as an organ donor.

Keep in mind that a good set of 12" Mitutoyo digital calipers only goes for $100-125 on eBay, so it's not worth investing all that much time and money in.
 
If you find a gear in those digitals that'd be a problem. There's nothing mechanical inside that case. I prefer dial calipers in my home shop, a couple weeks ago I bought an 8" Mitutoyo at the flea market for $20 because the needle was pointing down to zero instead of up. 2 seconds with a paper clip fixed them.
 
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