Thread: Advice sought from Electronics dudes

I bought a scale for the quill on my milling machine. The first two arrived with this condition:



Anyone care to shed some light on the likelihood I can successfully change out the LCD?

I don't think you will able to do it. I think the display portion is a integral component of the entire board, machine soldered and almost impossible to remove by itself.

That's assuming you can even get the case apart to get into the guts!

Stuart

FUBAR is not worth the time and effort asuming you can find a replacement for the lcd.

Yes it should be easily changed if you have a donor or whatever. They are not usually soldered but are connected to the board by a conductive rubber strip and clamped in place.

I kinda figured as much. I have two like this.

If two of them show similar problems it could be excessive clamping force due to an assembly error.

The other possibility is impact damage to the LCD. Not likely for two units but certainly possible.

- Leigh

Crap LCD.
Send it back.
Mitutoyo should be interested in their supplier being a bit optimistic over production parameters.
This sort of thing was a major headache during early development of LCD units, or so my former colleagues at Malvern used to say, but has been totally solved in production process control terms for a long time now.

Clive

I contacted Mitutoyo through their website. Here is the reply I got:

Hi Mark,
You have couple of options.
1. You can send Mitutoyo America Corporation for repair. Cost of repair is $107.20 + tax (for part) & shipping. We have to replace front cover module that include Main Board w/LCD display.
2. If you don’t want to repair, we offer trade in replacement with new & updated Quill Kit (053906B) for 25% discount. List price on 053906B is $306 + tax & shipping. You can see the detail specs on our website, Mitutoyo.com.
If you want to repair or replace, please send to below address. When you send, don’t forget to include shipping information, phone & fax number and contact person. Thanks.

Best Regards,
Win Chan
Mitutoyo America Corporation
16925 E. Gale Ave,
City of Industry, CA 91745
Ph: 888-648-8869 X 4221
Fax:626-961-8931

Looks like I will keep them as is.

Did you buy these new or used?

- Leigh

Originally Posted by aerodark

I contacted Mitutoyo through their website. Here is the reply I got:
Cost of repair is $107.20 + tax (for part) & shipping.

Even small firms can seldom move off their perch for under a hundred bucks, so that actually seems fair.

Any chance this model has a data output as later ones do?

Bill

Repair cost seems reasonable.

These were bought from a shady seller on ebay. I returned them (attempted to anyway) and got one that is issue-free. The two were returned to me after I attempted to ship them back to the seller. The address he gave me was bogus.

I believe they do have data outputs.

On second thought, before doing anything I would summon an exterminator to the shop, it seems that you have a very bad gremlin infestation

please take it apart and show use some shots of the board....if i could service the lcd i would try here Electronic Components Distributor | DigiKey Corp. | US Home Page for a spare. Will Mit. send you just the parts, maybe save you 50 bucks ?

Originally Posted by vettepicking

please take it apart and show use some shots of the board....if i could service the lcd i would try here Electronic Components Distributor | DigiKey Corp. | US Home Page

Aye. With ONE to do, I'd pop for the hundred bucks else trash it.

With two to do and one more someday-maybe, it should pay-off to figure out how to sort them DIY.

Bill

This is a mechanical issue, not an electrical one.

LCDs only turn dark in defined segment areas. The remaining areas have no electrical contacts and cannot change state under electrical control.

The damage shown will be caused by excessive physical pressure between the face and the back, like by an over-tightened clamp.

It might be possible to open the thing up, locate the problem assembly, loosen the screws and reassemble to achieve a satisfactory repair.

Electrical contact to an LCD such as this is accomplished through "zebra strips". These are tiny rubberized strips that run along each edge,
between the LCD and the PC board below it. The strips are actually alternating slices of conductor and insulator, at very fine pitch.

When the LCD is clamped to the board, pressure applied to this strip accomplishes the electrical connections.

It looks as though the upper clamp might be bent down, or the zebra strip may have come out of position and is putting excessive
pressure on the back of the LCD. Don't touch the zebra strip with your fingers (oil is an insulator), only with tweezers.

- Leigh

Originally Posted by The real Leigh

This is a mechanical issue, not an electrical one.

LCDs only turn dark in defined segment areas. The remaining areas have no electrical contacts and cannot change state under electrical control.

The damage shown will be caused by excessive physical pressure between the face and the back, like by an over-tightened clamp.

It might be possible to open the thing up, locate the problem assembly, loosen the screws and reassemble to achieve a satisfactory repair.

Electrical contact to an LCD such as this is accomplished through "zebra strips". These are tiny rubberized strips that run along each edge,
between the LCD and the PC board below it. The strips are actually alternating slices of conductor and insulator, at very fine pitch.

When the LCD is clamped to the board, pressure applied to this strip accomplishes the electrical connections.

It looks as though the upper clamp might be bent down, or the zebra strip may have come out of position and is putting excessive
pressure on the back of the LCD. Don't touch the zebra strip with your fingers (oil is an insulator), only with tweezers.

- Leigh

That CAN work. Sometimes.

Seldom worth the effort, as earlier-generation nematic-twisted 'crystal' displays had design and chemistry issues anyway. OP has the 2 out of 3 'statistical sample' right in front of him.

Worse, they are not easy to read in unpredictable lighting even when undamaged. Once anchored to a machine tool, they cannot be as easily angled about as a hand-held or benchtop test meter .

If one is to invest any 'free labour' time in such, I'd want to see if I could use the data channel to remote - even mere inches - to a BETTER display. Or at least one that was on an independent mount that could be angled for best eyeshot from one workpiece to another.

That could turn bargain components into a better overall system than wot ships even at a much higher price.

Someone is bound to have done it already, and more than once, so let us hope they have left a trail on the 'net that isn't too hard to find.

Bill

Pretty easy repair, give me some measurments on the display glass in thousanths and I'll see what I have to fit it, if its a standard size lcd same as the mics I have them and also have one of an older style scale, the best bet would be to dissassemble and snap a picture of the connecting area of the lcd in addition to the dimensions there are alternating bands visable that are spaced differently on the lcds, not the best picture but you get the jist

Mitutoyo sells a digital display that connect to the spc port

Originally Posted by thermite

That CAN work. Sometimes.

Admittedly this would not be the preferred solution for a tool used 8 hrs/day or more in a business.

The __assumption__ here is that this is a hobby/recreational environment, in which time is more readily available than money.

- Leigh

Originally Posted by aerodark

Anyone care to shed some light on the likelihood I can successfully change out the LCD?

It is very obvious that pressure was applied to the top of the lens. You should investigate how this might have happened
by looking at the shipping package. You can apply for a damage claim to the shipper if the outer-most box was crushed.
Otherwise your ebay seller is a ... If these were sold as brand new then you should not have to be stuck with them in this
condition. I doubt that you will be able to obtain the same lcd as a replacement part from Mitutoyo even though LCD's like
those are a dime a dozen.

If all else fails ask if you can get a discount for repairing two.

Or if you want to mess with it:
Carefully try to move the lens so that pressure is reduced in the dark area. You might get lucky.
If it was me and I was going for a repair then I would take it apart.