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The Shop => Electronics & IC Programing => Topic started by: picclock on February 01, 2013, 10:47:18 AM

Title: DRO LCD Display failing ?
Post by: picclock on February 01, 2013, 10:47:18 AM
I have a 300mm DRO display on my mill and its becoming progressively more difficult to read the display. I've changed the battery to no effect. The best viewing seems to be from a very low angle ~20 degrees or so. I think its something to do with the LCD display itself. I've taken it apart to make sure the rubber connector between the board and display is OK but that all appears fine.

Does anyone know a method of resurrecting these - or any other potential solution ?

Many Thanks

picclock
Title: Re: DRO LCD Display failing ?
Post by: Bluechip on February 01, 2013, 11:03:52 AM
May be there is a contrast pot. somewhere on the electronics board.
 
The 4x16 and similar types I faff around with always need to be adjusted for each display. No two are alike.
 
When they are 'somewhere near' right they can have a wishy washy look.
 
Although these are the 7x5 dot type, not segments, so maybe it does not apply. ???
 
Dave BC
 
 
Title: Re: DRO LCD Display failing ?
Post by: philf on February 01, 2013, 11:35:45 AM
I've changed the battery to no effect. The best viewing seems to be from a very low angle ~20 degrees or so. I think its something to do with the LCD display itself.

picclock

Have you checked the voltage on your new battery?

The LCD displays on bike computers go very faint when the battery is low and are only easily readable from a shallow angle.
Title: Re: DRO LCD Display failing ?
Post by: vtsteam on February 01, 2013, 11:47:11 AM
I had a similar problem with a digital caliper -- the display went dim, I replaced the battery and had the same problem again. On checking the new battery the voltage was low. But I don't hink it was low to start with. I think something in the caliper circuitry drained it very quickly. Not sure. I did try several new batteries right out of the store package and nothing helped. In fact I can't get the display to be visible now at all.

It worked well for maybe 2-3 years before the problem. I've since read of similar owner problems for these style calipers online.
Title: Re: DRO LCD Display failing ?
Post by: picclock on February 01, 2013, 01:14:04 PM
The first thing I did was check the battery voltage of the old cell and the new one. Both were something like 1.54v which is about right. There is no contrast control on these so nothing to adjust. It might have been the cold weather that set it off, possibly causing a change to the LCD liquid. However I have managed to bodge it up by using the read head off of a 6" caliper. This will only read up to 199.99mm but that's OK as I can just carry the 100 if I need that much, and the rollover is precise. The donor caliper head was from an ebay cheapy but it seems to work just fine.

From some of the comments it may be some sort of built in failure mode, although I still have my first digital caliper which is still going strong and is as accurate as the best of them - at least 6 years old now.

I think life throws the little challenges at you to slow you down  :coffee:

Many thanks

picclock
Title: Re: DRO LCD Display failing ?
Post by: philf on February 01, 2013, 02:04:39 PM
Picclock,

Have a look at:

http://www.machine-dro.co.uk/spare-parts.html

There are a few read heads for 300mm scales.
Title: Re: DRO LCD Display failing ?
Post by: Deko on February 01, 2013, 05:45:08 PM
This thread has got me thinking, :poke: what can you use a realy dead one for ??? The first thought i have just had (forgive me for this ) , is for removing old grout !!!!   Anyone any ideas for workshop use ?

Cheers Dek.
Title: Re: DRO LCD Display failing ?
Post by: vtsteam on February 01, 2013, 06:01:39 PM
An outside or inside caliper?

A scriber?

Twin back scratcher?

Free gift promotion?
Title: Re: DRO LCD Display failing ?
Post by: picclock on February 05, 2013, 02:33:48 AM
@philf

Thats a useful link, many thx. Lots of choices with extra functions.
How does the tolerance function work?.  I also can't think of any reason one would need a hold function. I should probably get out more .. .

Many thx

picclock
Title: Re: DRO LCD Display failing ?
Post by: philf on February 05, 2013, 03:32:10 AM

How does the tolerance function work?.

I also can't think of any reason one would need a hold function.


Picclock,

See http://www.machine-dro.co.uk/150mm-6-digital-calipers-with-tolerence-function.html

I've never had cause to use the hold function but think it's if you're taking a measurement in an awkward place where you can't see the display. You can adjust the caliper, press the hold, remove the caliper, finally read the display.

Phil.
Title: Re: DRO LCD Display failing ?
Post by: dvbydt on February 05, 2013, 04:43:11 AM
I have no idea why it worked, but I held down the on/off button down whilst inserting the battery and the display on my 75mm pocket caliper came back to life!!!!!!

Worth a try? Can anyone explain please? Is it so sort of reset function?

Ian
Title: Re: DRO LCD Display failing ?
Post by: Fergus OMore on February 05, 2013, 04:51:54 AM

No?

Deleted!

N