repairing devices with obsolete LCD displays

Thread Starter

nitrous2020

Joined Sep 29, 2020
6
Any thoughts/links that might be helpful in replacing obsolete LCD screens on proprietary devices?

The manufacturer no longer repairs the
Eschenbach SmartLux Digital Portable Magnifier and I have a couple units with broken LCD screens.

I've looked at the screen information on the back of the display but there really isn't anything useful.
Is there a resource that would assist in replacing these screens?

Does the ribbon cable/chips on the display give any clues?

It seems a waste to trash something that is so expensive (>$1000) and could be of help to so many persons with limited vision.

Thanks
Doug

 

Ya’akov

Joined Jan 27, 2019
8,505
Welcome to AAC.

Photos 0of the internals would make helping possible for someone who doesn’t happen to already know this device.
 

hrs

Joined Jun 13, 2014
390
The Eschenbach site claims a display resolution of 860 x 480 which seems unusual. At a glance neither Mouser nor Digi-key carry LCD screens with that resolution.
 

MisterBill2

Joined Jan 23, 2018
16,534
Do they still sell that model? If not, then possibly they could part with a copy of the circuit,or any other information. It seems as though the sensor must be an integral part of the system, so you can discover the exact number of rows and columns and learn the actual resolution.
It might be that the screens of some flat screen computer monitors will be similar. That is the one possible source that I can think of.. One question is how the scan proceeds.
 

Jon Chandler

Joined Jun 12, 2008
852
Story time:

A few years ago, I did a small-scale project for the FAA (Federal Aviation Administration) in the US. It's important to note that the FAA is still using critical equipment built in the 1970s (which really can't be that long ago as that's when I graduated high school!), so the goal of a long service life was one of my key design parameters.

This relatively simple device has two 3-digit displays and 4 pushbuttons. I had some battles with the customer, who thought a low-cost graphic LCD & touch screen would be ideal. I was adamant in saying no, for several reasons:

● The service life of low-cost LCDs is unknown.

● Replacement LCDs with the same fit, mounting arrangement and driver are unlikely after a few years.

My solution? 0.56" 7-segment LED displays and socket-mounted high-cycle industrial switches from (a pain in the ass) major supplier.

This size 7-segment LED has been around for years and will likely be for decades more from many suppliers, and is rated for a service life of 50,000 hours. In the worst high use case, I calculate that is in excess of 15 years, and in most cases, 30+ years (long after I care about it ).

The switches are rated for a million cycles, providing a similar service life to the 7-segment LEDs. Because the switches are sometimes subject to a lot of abuse, they plug into sockets and are field-replacable with just a screwdriver.* Will they be available at some point in the future? Who knows, but they are from a popular line of a major manufacturer.

* The use of sockets was overkill according to some technicians who looked at the design. "Any technician can solder a pigtail on a switch to replace it." True enough, but that pigtail is a weak link that doesn't need to be there. And plugging in a replacement switch is a 5 minute fix compared to "I'll get around to it." Also a major consideration for this small-scale project – I really hate soldering pigtails to switches! In this case, it would have been a lot of wasted time and effort.

Sorry for the short diversion in the thread!
 

MisterBill2

Joined Jan 23, 2018
16,534
Certainly video display technology advances will assure us that today's NEW THING will be obsolete and out of production and not available in a fairly short time.
AND J.C. did not mention all of the other grief associated with touch screens.
But for the devices mentioned by the TS it might be possible to adapt a monitor screen. Maybe..
 
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