Omega Equinoxe 1655 LCD Display Repair & Restoration

Years ago when working for Apple, we were in the same silicon valley industrial park as several surplus shops. I would take my lunch breaks (or stop in after work.) Going through shelves and shelves of the stuff dreams were made from.

Much of the items came from the trash dumpsters.

There was one shelf of bare glass LCD displays. Possibly 100s of them. No drivers no documentation. Dome of these were calculator or stop watch displays. Such items cost a few cents each. Such displays were/are common. they are cheap, take no power and are easy to make. The glass sputtered with indium tin oxide and etched then glued together with epoxy and filled with a nematic fluid.


One company I worked for made transparent calculators for placing on overhead projectors.



How they worked was by placing a low frequency wave onto the electrodes, what twisted the polarization of the crystal. By varying the timing of these waves through front and back planes, the segments could be multiplexed reducing the connector count.

By the early 2000s this was summarized in a nice little trade journal article part of which is shown here.



I used this to write a simple microcontroller project which I posted to github. https://github.com/sheepdoll/LCDJupiter I also spent a lot of time etching pcb boards and working out how to get one of the stopwatch displays to work. I did find part of my notes, but not that one. The goal though was to make an updated version of this project to fit into something like and old apple watch case.


LCD watches became so common they were included in breakfast cereal.


Sometimes watches included both an analog and an LCD display.

I have been wanting one of these for 50 or so years. I did get the Seiko in a box of junk. I was able to find a completely trashed Omega equinoxe. Which I now call the WOM watch or waste of money.


I do not know why but this mess of a watch makes me feel really good. I think it has a lot of potentional and a lot of rabbit holes to explore.

It is really hard to mess up an LCD display. So I figured this would be the one thing I could salvage from the rusted mess.

I got out the old LCD stuff and built a tester out of some learn to solder smd module kits from the maker faire.


These were simple modules what would blink and LED and could be pinned on like a button. This one was heart shaped. Google AI produced some simple code what could generate a basic signal that would turn on segments and used for locating the data signals. What I did not have 24 years ago was the microprobes what could clip onto these small parts.

I verified the test board with an old cash register display, which fell on the floor and got stepped upon (I was wearing socks). It still however works, but the crystal leaked on one side. Which is a good test for a failure mode.

I also dismembered the Seiko. Managing to loose one of the gears. But I wanted the LCD display as a reference to the 1655 equinoxe display.



I could get not segments on the 1655 display to light. I only have the one really tiny probe. most of the probes I have are for larger devices .5mm rather than 001mm. So I found that I could clip onto an old balance staff to make a really tiny probe. These displays are really small.

A common failure when segments do not light is faded polarizer film. I had some film left over from the old projects. This however was not the solution to getting the 1655. display to light segments.

The photographs of the 1655 display show what looks like some sort of stuff staining the surface. Attempts to remove this scratched the polarizing screen. Which is held onto the glass with some sort of sticky glue like tape.

Removing this shows the staining is between the glass plates.


I was able to get a decent macro photo of the display. The old film shows zero polarization. The replacement film shows no effect. In cleaning the residual glue with IPA and contact solvent (Heptain?) I noticed it wicking passed the epoxy seal. There is no nematic in it what so ever.

So this display failed completely ;(

Which actually makes me feel like I wasted the money in a good way. Disappointing as I was looking forward to probing and working out the multiplexing.

In the auction photo the display does look trashed with a sort of satisfying eerie glow from the back reflector. A true case of what you see is what you get.

I set all this aside and decided to take a look at the circuit board. The motor coil measure good on the analog side. Since the 1655 shares parts with the 1365 (what are really different watches.) I got some 1365 movements. I also built a little tester for the 134x movements.

The question was there any functionality of the electronics module?

These tick at a rate of once per second. So waiting for a motor pulse is tiresome. They do have setting modes. I was able to acquire a mainenece sheet from and Australian eBay auction. This allowed me to look at the electronics module with a scope.
One really does need a dedicated machine like the Alitest and Deltatest mentoned in the Maintenance documents.

This uses inductive coupling to read the signals from the electronics modules. The microprobes and balance staff do work after a fashion, but it is hard to get photographs of the signal traces.

The important thing is that the signals are there on the electronics board. The quartz is oscillating, the lcd back plain has waveform and the motor pulses are present in setting mode. Most of the damage seems to relate to the alarm function. Enough to continue throwing bad money after this project. (And I got a bonus 1365 watch and another 134x watch working.)

Quite a few of the 1655 parts are available on the secondary. Markets. There is something called ScotchWatch which I never have tried. So I ordered a new module. There are 8 in stock. A French seller had multples of the corroded parts. I ordered a new contactor plate from Dubi in the UAE where there are also multiples listed. The French parts have arrived.

I received photographs of the new display, where it can clearly be seen that the polarizing film is intact and the edges black where the nematic interacts with the epoxy seal.



So there is hope yet for this project.

I noticed that in a lot of these it is the analog side what has failed, so will be interesting to see what happens when I clean and reassemble those parts.

I also note that it is better to purchase complete broken watches than fragments of broken watches. This is probably going to cost me more than market rate in the end. Especially that I am still missing the bezels and cover crystals (one which contains the alarm speaker.)

(This post has been in the work for the last few months, So I am surprised it did not turn into another stream of consciousness wall of text installment.)

Remind me to never get into detailed repair on LCD watches.

Love the green Weller station. We had them in our lab when I was doing a NASA standard soldering course. Mine had a yellow foam sponge "tip wiper" though.

So while waiting for the new LCD screen. I decided to see if I could take the old one apart.

This was off to the side while I was destroying motor coils.

Broken Apple screens are separated by running a fine wire between the display and glass touch panel. Since the top of the display was wicking in the IPA. I was able to insert the wire. This got as far as the staining from the old nematic crystal.

I had not got out the acetone, and was trying to decided if I wanted the hot thingy used for apple glass. So I set it aside with the wire still in it. Was planning to get the phone out. While focusing on the motor coil I heard a plink.



Sadly the thing I did not want to happen did. One of the glass plates cracked. Such the nature of watchmaking. Even when taking things slow there is still that 30 seconds you would like to have again.



So little chance of seeing if I could glue it back together and possibly transfer some nematic crystal from the display I stepped on. The break is below the back plane so it might still be possible to glue some of this back together.

At least this part is readily available. I had never used Scotch watch before. Bid dicey doing a transaction by email. But it worked. The new display came in original packaging. With room for the broken pieces.

It can be hard to let go of the broken part. There is a feeling that there must be a way to fix it. Especially when this part was the whole reason I bought the watch.

Still waiting for the corrector plate to come from Dubai in the UAE. Tracking indicates it should be here by the end of the week.

As long as it is not sisyphean. Do not need to push any rocks up a hill.

The Arabian parts arrived just now from Dubai, UAE.
Tracking was a bit weird. Ebay only reported the Emirates post which ended with the duty needing to be paid.

Contacted the seller who sent the correct domestic information. For some reason DHL called the house landline number not the cell which I gave the seller. Once paid the part arrived.



Everything looks good. Original packaging too. Pretty good for 35 bucks. Of course the actual cost was like three times that since I had to effectively pay the taxes twice. If I read things right the actual tariff was only like a buck fourty five. The rest was shipping and handling fees. Local tax is also around 10 percent.

Before I put this back together I need to put the other watches I took apart while waiting for these parts.

Will be interesting if this works.