Mitutoyo 192-611

[awemawson]

Many months ago I bought what should have been a very nice Mitutoyo Digital Height Gauge. Initially the seller took weeks to send it (bad signs), then after I raised an ebay 'case' he sent it, but only wrapped in a single wrap of bubble wrap with no outer boxing, and by a common carrier.

[awemawson]

Needless to say I was not surprised to find that it didn't work. Loads of argy bargy with the seller - and raising another 'case' I got a refund and told him to arrange collection, and if not collected in three months it would be scrapped.

[awemawson]

It's been sitting on my desk now for well over six months, and the seller isn't contactable 'no longer a registered seller' on ebay. So I thought that the time was ripe to look inside and see if anything could be done before chucking it out.

This is what I found:

[awemawson]

Now as you can see, the 6 way ribbon cable (which is actually 'flexible pcb') is torn that connects the encoder head to the main pcb.

Hard to see how this could have happened even in upacked transport, as the head and main pcb are both fixed to the sliding 'chunk' and don't move relative to each other except when it's dismantled.

Also one of the rubber 'conformal' press buttons is missing, and a bit of polystyrene has been put in it's place to push the external button 'out'

Conclusion: someone's been in here before and been hamfisted and torn the ribbon and lost the rubber contact 

I thought it worth while at least attempting a bodge, replacing the flexy pcb with wires. It's all VERY tight in there as you may imagine - I used the finest ptfe covered stranded wire that I have  - Tygaflor A spec 7/0.048 which ends up 0.65 mm over the insulation and is a pain to strip neatly.

Put it all back together, tried it - zilch, nowt, nothing 

Whipped it out again, connected up a lab power supply to the main pcb, tried again - hey it works  Rather a lot of faffing around with the battery mounting arrangement (3 AA cells) and I've ended up with a height gauge that works but has one button NOT working due to the missing rubber 'contact'

[awemawson]

I moved the missing rubber to the 'preset' function, so that the 'Zero' and 'hold' work, so the gauge will be useful, but what I really need is a replacement rubber contact like this:

[awemawson]

I'm sure that something similar must have been used on other equipment - anyone have any clue where I can get one?

[Manxmodder]

Andrew,I don't think this should be too difficult to fix, I have seen the contact buttons from a cheap digital calculator reshaped and modified to replace knackered ones on more expensive/functional items.

Open an old rubber keyed calculator up and see what you can find.....oz.

Edit to add: looking at the size and shape in your photo maybe a contact button from a playstation hand controller or similar,looks very similar.

[wheeltapper]

Hi
I've got a tub full of those things.
I'll have a sort out and see if any are the right size.

Roy.

[awemawson]

Well a VERY nice man called Wheeltapper (Roy) sent me a selection of buttons - and with a bit of judicious pruning I've grafted one of these into the 'Preset' button position

[awemawson]

So dismantling yet again, I removed the polystyrene dummy button, cleaned up the pcb (which was presumably originally gold flashed, but is now bare copper) pruned and placed Roy's button and put it all back together

[awemawson]

I'm delighted to say that the 'preset' button now works - I just need to work out which combination of buttons does what, as at the moment it just sets and increments the most significant digit - I can feel a bit of web trawling coming up 

Roy thank you so much for posting the buttons - very much appreciated 

[wheeltapper]

HI
Thats great, I'm glad one of them worked.
you can put the others in the 'comeinhandy ' box.

I've had those kicking around for about 15 years, at last they found a use.
well done.

Roy.

[awemawson]

I've just done a quick 'Calibration Check' - 100 mm gauge block sat on the Bridgeport table having zeroed the gauge on the table and was amazed to find it read correctly to 2 decimal places ie 100.00 mm.

Quite surprised after all the poor thing has been through