strange electronic caliper fault

I don't know if any one else has come across this. I was measuring up a pulley this morning and the readings were not as expected. A quick check showed that the electronic readout was showing exactly half of the actual dimension. i.e. 20 mm showing as 10, 40mm showing as 20 and zero showing as zero. The usual cure for electronic wobblies is to dis-connect the power supply for a while, so I removed the battery. While it was out I thought I might as well dismantle the caliper and clean the scale and sensor PCB. Having done this, it was re-assembled, the battery re-fitted and it is now working normally. However, if I use it in future, I will regard it's readings with a certain amount of suspicion. The caliper is a cheap "Workzone" model from Aldi, which I have had for about 6 years and never had problems with it previously.

You have just failed to reassure yourself by making so many changes at once. Low battery voltage, scrambled electronics (possible dirty contacts?), dirty contacts/sensor.

Better to check things out sequentially.

Battery check, battery change if low voltage.

Battery contacts check, OK after cleaning?

Then move to mechanical possibilities.

Tat way you may have determined a simple explanation for the failure.

Display was OK so battery fine, but checked it anyway. Also looked at contacts when battery was out. Basic stuff which I didn't think worth mentioning.

The display will work with a nearly dead battery. The measurement will not. Battery that is low will display fine but with the wrong readings.

Mine started playing up after five years of workshop use, display was all over the place. Took it inside and did a complete strip down allowing me to get at the read head. Cleaned it all down, wiped all the contact surfaces and reassembled, has worked fine since. I think it is the build up of oily residue which hardens and results in loss of full contact between moving parts.

Didn't some Aldi calipers have a radius function?

Some have a radius function; also some have functions that are not accessible as full complement of buttons isn't fitted.

An extended press on a button or a glitch may have sent your caliper into a 'hidden' radius mode.

Neil

I've had the same problem a few times, and in each case it has been resolved by replacing the battery; contact cleaning etc didn't help.
This has only happened with the cheap ones from Aldi & Lidl, which I use as my normal go-to ones for general measurements or working on the car/bike etc. Whilst unfortunate, I'd not be too bothered if I dropped or damaged them in some other way, unlike my Mitutoyo or Insize ones.

The fault which caused me most bafflement, and several junked jobs, was a set which missed out 13mm, jumping straight from 12.xxx to 14.xxx
I never did find the fault, so they are now retired somewhere.

Bill

The other day I used my digital caliper and fit it to the mill, to more easily measure depth etc using a probe made, works like a charm.
I then went to the shop and bought a new one from a well known brand where I live. On testing I found it not zerowed 100% of times even wiping tips with my finger, so I went back, a similar one does the same, both new batteries tried in store. I then decided to buy a Geodore one at 3x the price, instant success, it zeroed like a charm every time, the store manager agreed and will take it up with company which also sells Accud.
So for me this was an interesting experience on the shop floor.

That is quite possible. this device only has 3 buttons - on/off, inch/mm and zero.

if you have lost faith in the accuracy of its readings, a new one from Aldi/Lidl won't break the bank.

you only need to ruin one piece of work for it to have paid for itself.

Probably, cleaning was all that was needed. Reassembly needs a little care to ensure that the shims (if any ) and gib strips are replaced correctly, so that the grubscrews locate in the holes...

Sometimes, for some unknown reason, either the readings remain fixed, whatever the jaw position, or are absolute nonsense.

The instructions say that if this happens, remove the battery, wait 30 seconds and then replace, and operation should be normal again.

Mine came, YEARS ago from LIDL, and are falling apart (Thumb wheel missing,, battery cover held in place with an O ring, but still functioning. )

Howard