Sort of a folowon to the thread https://omegaforums.net/threads/omega-1342-stepper-motor-oscillating-back-and-forth.165357/



And a full bench shot


Using the data sheets I full disasembled the movement. Most of it is there. The battery clamp is missing. One of the screws on the calendar was a bit stuck.

Given the price (20 bucks US) and the condition. I suspect this movement was immersed in water or something. No corrosion, but everything is dirty. There is also some copper sulfate outside the battery compartment. I doubt it had been disassembled. Everything seems really dry and dirty.

I have not yet attempted to power the electronics. I needed to get a stem first, which came over the weekend.

This has a push button set. There is a clutch wheel, which is used for setting the calendar. Good thing there is a full data sheet. There is also a magnetic clutch on the hour wheel. I have some magnetic sensitive film. So I thought I would see if I could read the magnets with it. This stuff does not quite have the resolution to read credit card strips. It will read strong magnetic fields.


The top plate of the motor does indeed have magnetic poles. I do not think the motor would be easy to disassemble. It is probably glued together. The motor does turn freely.

The tip of the seconds wheel may be broken off as well. Looks like these come with three different heights depending on the dial.

This model seems to be fairly common on the auction sites. (I even got some BIN offers looking for examples.) So I probably could get a complete one for around 150 or so.

The hardest part is to resist the temptation to get a more complete watch. Or to source the missing parts on this one. I am still waiting for the rest of my Black Friday binge. Most of the stuff on the bench relates to landeron chronographs. And I need cases for my chronograph movements. So easy to be distracted by other shiny watches.

Parts for 1340/1342/1345 do seem to be out in the wild. Probably as when the motor goes, there is not much what could be done.

As noted I have not yet tried powering the electronics. I want to clean the mechanics first. The mechanics are really well made with lots of jewels. Some of the goals for this experiment is to see if a modern microcontroller can operate the motor.

The modern chips are small enough, but they seem to want 2.7 volts rather than the 1.35V a fresh battery can supply.

 

So I kina went a bit crazy in this department.

First the contental Can company one. With parts from the junked watch I got it to almost tick. I have not cleaned it yet. I did notice it had a cap on the motor that the old one did not. Not sure if this is a later refinement or if a lot of watches are missing this cap which holds the stator in position.

Last week I got this POJ. Which is only really a case. And that went for next to nothing. Someone else nabbed the motor. Have not checked the electronics yet as there is still a circuit board.

I thought the candy sprinkles might sweeten it up a bit. I went for it as the case and crown could be useful. Surprisingly people value these due to the Omega name. Not sure if the factory repairs them or not.

For someone with my skills. Programming a new chip is something I can do. Downside is the easy to program chips want closer to 3 volts.

Not sure how easy it would be to make a workable micromotor. The data sheets actually give most of the tech info. It might be possible to repair such things. I have not seen many working or not listed. Most probably wind up in the dust bin. There is so much fokelore out there that the vultures tend to circle the carcass on these things.

Batteries on these are also problematic. The closest replacement does not fit. There may be 3 volt alternatives what will fit into the battery well.

At least I have some parts to play with and experiment upon.

 

The smallest 3V lithium cell I know of is CR1025. The code implies 10mm diameter and 2.5mm thickness. I believe the original mercury battery has an 8.9mm diameter, and the well is about 9mm. I don't know if there is enough clearance to grind an extra mm.

 

charge pump might also be an option. Some battery adapter use a diode to drop the voltage on the silver oxide down.

I have a lot of AVR Tiny 25 and 85 8 pin chips. It has been a while since I looked at the data sheet. I think the brownout is 1.8v so the 3v is more for insurance. As I recall the stable voltage is more when one is writing the flash memory.

My preference is to do nothing irreversible. At least to the mechanics. The battery sticks quite a bit above the movement. The frame seems to be common positive. Which sort of makes sense as it is easier to switch to the negative rail.

I have the extra board now, so can see how easy it would be modify it for the programmable cpu chip. I think most board houses now can mill out any shape on the pc board. They always seem to ask for the thickness.

The next step would be to see if I can program a wave generator and scope out the motor pulses.

Not sure when I will really have time for this. Mechanical watches are so seductive, especially where they start with a 99 cent opening bid.

 

If you use the original chip, you can use 329 silver oxide battery directly without a diode to drop the voltage. I have been using 329 for years in 1342. It does not have the same capacity as the original mercury 388 so it lasts a little less than a year (9-10 months). It's a bit smaller than the mercury 388, and you should add a small ring adapter to secure the 329 in the center of the well. I 3-D printed one. Depending on the case back clearance, you may also be able to use slightly thicker 384 battery with higher capacity.

 

and another one...

These are all over the place in price. Looks mostly complete. Could not figure out in the auction photo what the contact wire was. Turns out it is the sweep hand.

I notice a lot of these have service award engravings. I guess that keeps the prices down.

Not sure if there is a trick to straightening out the sweep hand. Usually when they are this bent, bending them back breaks them.

 

Stopped by Batteries + Bulbs on the way home from the Pipe organ place today.

Two of the movements actually tick! One I just got the other is the Continental Can one.

Also got some 3V cells. The smallest they had was the 927. I did get a 1025 to see if either will fit in the well.

These watches seem popular online. I missed out on a couple auctions. I noticed that another CCC went this afternoon for a bit more than what I paid for the one I have.

I am now up to three cases and four movements. Someone stripped the motor from the connie as well as the SN plate, which should be a 1345 or 1346. I have seen Day Date offered with a 1342 name plate. I think the main difference is the jewel count.
I did grab a seconds wheel.

Still need to figure out how to iron out the sweep hand without breaking it. I think I only have the one sweep from the CCC movement.

 

If you're going to replace the original circuit with a AVR or another MCU, I'd use a small step up converter and the original 1.5 V cell. Something like XC9145 from Torex is small enough to fit on the PCB and does require more than an inductor and a few caps.

 

Another easy option is to use two 315 batteries stacked up. 315s have the same diameter as 329, and the height of two 315s is 3.3mm, exactly the height of the original 388 mercury cell. You'll need a thin plastic cylinder or some electric tape to protect the sides from short circuit.