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Problem with Starrett 721 digital caliper

MARVINGARDENS

Aluminum
Joined
Dec 13, 2014
Location
Central Valley, CA
I received a Starrett #721 digital caliper a few years ago as a gift. I never used them and they have been sitting inside a sealed plastic container in a drawer ever since. I opened the case and took them out this morning, When I slid the battery cover plate to activate the unit, only the bottom half of the digits appeared. I went to Radio Shack and got a new set of batteries and the results are the same.

The unit appears to be measuring but the upper half of the screen only appears when I press and hold the "hold" button.

Am I doing something wrong?

I'm wondering if repair would cost more than replacement?

Thank you.

Bob
 
Shot LCD screen, or the lower half of the screen might not be getting power form the main board, send it back to starrett.
 
Most LCD screens are not hard-wired or soldered to the circuit boards. Instead, there is a laminated strip of plastic with conductors in it, that us sandwiched between contacts on the display, and contacts on the circuit board.

Usually, there is one strip at the top of the display, and one at the bottom, but sometimes there is only one.

You may be able to open the caliper up and clean off the contacts on either the circuit board or the display board, it sounds like yours is just dirty, and that's why pushing on a button causes the display to work.
 
Thanks very much for your speedy responses.

I just sent an e-mail to Starrett and will see about sending the caliper in.

I'm wondering if I should avoid electronic measuring tools in the future.

With everything I am reading, I am wondering if I should avoid Starrett? When I was in school, Starrett was the brand to have.

Thanks again.

Bob
 
If you decide to try to fix the problem yourself, be advised the problem is probably faulty connections between the circuit board and the glass LCD display. The connection between the two is in the form of a (usually) silicon rubber strip with built in conductive channels. These things are called Zebra Strips or elastomeric connectors and the problem can sometimes be cured by dis-assembly, a scrupulous cleaning and reassembly. Note the "sometimes"!

Google searches will turn up many useful tips.

Regards
 
I'm wondering if I should avoid electronic measuring tools in the future.

With everything I am reading, I am wondering if I should avoid Starrett? When I was in school, Starrett was the brand to have.

Thanks again.

Bob

I've used my cheepie digital caliper for years....thousands of measurements. I hate to say this around here, but I trust it as fat as calipers go. Never given me a false reading, and always within a half thou for under 1" dimensions. Don't have a over 1" mike to back up readings any higher than that.

If my cheapie is good, your Starrett is better, you just got a lemon.
 
You may be able to confirm that the problem is with the Zebra strips by pressing down along the top or bottom edge of the display. If any portion of the display returns to normal it means the additional pressure has improved or re-established electrical contact. If pressure applied along the entire length of either or both the upper and lower edges of the exposed LCD returns the entire display, a thin paper shim between the display and its bezel might be a jerry-rigged fix.

This all assumes the connection between the display LCD and circuit board is made using Zebra strips - which is a fairly safe assumption considering it's the cheapest way to do it. Those little Zebra strips... Thermal Interface Materials from Fujipoly America | Design Guidelines - Connectors ...are only about 10¢ apiece but from what I've read are nearly impossible to get (unless you order 1,000 of them).

Regards
 
I'm not a fan of early Starrett digital stuff. More recent seems better. I had #722 and fixed them (there's a page on my site), but they still tended to eat batteries at ten times the rate of Mitutoyo, so I got rid of them.
 
I contacted Starrett and received an e-mail reply that my calipers were obsolete and no longer supported.

They did say they offered these calipers as replacements.

799A-6/150 $102.90
OR
798B-6/150 $162.40

The 799A price is a few dollars less than I could buy a new set for from Amazon. The 798B about sixty dollars less.

Not exactly free replacements but I can't blame Starrett for me leaving an unopened package in a drawer for a few years.

I shipped mine this morning and they are supposed to contact me when they examine them.

I'll make a decision then. I am leaning towards just picking up a used set of dial calipers.

Thanks.

Bob
 
Mitutoyo digimatic absolute are excellent calipers, the best as far I can see. You have to turn them off though or battery will die.
And DON'T leave the battery in if you're not using it for while. Starrett makes great tools but their electronic tools....?
 
I had a similar problem with my Starrett 721 caliper, it simply just stopped working. Contacted Starrett, it is no longer repairable and they offered me a new one at basically the same price I can buy it on Amazon. BTW, the replacement ones are made in China. I purchased a new Mitutoyo Dial caliper, works great, no batteries to replace! It was difficult to toss the Starrett unit in the metal bin, but I had no other option.
 
Thanks very much for your speedy responses.

I just sent an e-mail to Starrett and will see about sending the caliper in.

I'm wondering if I should avoid electronic measuring tools in the future.

With everything I am reading, I am wondering if I should avoid Starrett? When I was in school, Starrett was the brand to have.

Thanks again.

Bob

Just avoid Starrett electronic stuff. Mitutoyo is way better. I have 20+ year old Mits as well as brand new coolant proof ones. Batteries last 10x as long, and if they do die send them back to mitutoyo and you get a new pair for half price.
 
I had a similar problem with my Starrett 721 caliper, it simply just stopped working. Contacted Starrett, it is no longer repairable and they offered me a new one at basically the same price I can buy it on Amazon. BTW, the replacement ones are made in China. I purchased a new Mitutoyo Dial caliper, works great, no batteries to replace! It was difficult to toss the Starrett unit in the metal bin, but I had no other option.

I hate to break the news but as good as all digital calipers are now made in China. The top brand names do monitor what gets made for them. Even a good bit of Mitutoyo electronics get made in China but they have a patent that prevents blatant copying and Mitutoyo are big enough to have the clout to do something re copies.

I don't always get the battery "problem". A battery costs around $2 to $3 and if an extra is kept in a refrigerator (not a freezer) then - no problem. The main types of digital caliper batteries are 1½v LR and SR (SR being better than LR) and CR3012 (3v).
 
With everything I am reading, I am wondering if I should avoid Starrett? When I was in school, Starrett was the brand to have.

I suggest you get a Mitutoyo Absolute Digimatic Caliper, 6" long. If you shop around you can get them new for around $100. If you take good care of it and follow the instructions (about exact type) when replacing batteries, it will last many years and be accurate for that entire time.
 








 
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