Longines lcd problems

[Adam]

i just traded an early Longines lcd watch. The lcd shows fine and the colons flash but the numbers don't increment.
There is a brass sleeve runs around the movement a what looks to be a brass connector sticking out from the movement. Both I have cleaned.
I think the unit is sealed as I cant see any screws.
Attached are a couple of photos. Any help really appreciated as id love to get this beauty running properly. I can take more photos if necessary.

Adam

[Adam]

Does anyone even recognize the module? I had it apart again. I have a versitime testing machine and followed the instructions for testing the crystal and that seems OK at 0.4 according to the booklet.

Any ideas anyone?


Adam

[rewolf]

If the colons flash at the correct interval, the oscillator is running.
Can you set it? If yes, then it's not stuck in setting mode either.
Some watches need an additional press on a button to actually start after setting. Did you check this?
IMO if it's not the above most probably it's a logic fault inside the chip, clock signal not routed to counter stage.

[Adam]

I can set the minutes but the top button which I assume is the hour doesnt do anything. I take it it doesnt sound good? Do you recognize the board? It may be it has to sit alongside my Microma DSMs in my non working museum drawer.


Adam

[Old Tom]

Actually there are two boards in this watch- the top board you can see with the crystal on is purely the oscillator board, the main timekeeping chip is on the board underneath and is probably an Intel/SSS 5201. This chip does have a non-run state for synchronisation purposes- I would suspect a mechanical failure somewhere- probably a speck of grot bridging the run/not run contact leaving the watch in a stopped state. Your versitime machine should be able to "hear" either the crystal or the LCD panel if the oscillator is running.

[charger105]

Hi Adam.
Nice module. I haven't seen one before. Looks well made.
It may be a contact problem with the buttons. The 2 little brass pads look to line up with the buttons. If so, try shorting the top of the batteries to these little brass pads (effectively bypassing the buttons). Hopefully this will start the time-keeping function.

In case you hadn't realised, the IC indicates a 1974 date. Nice and early !

Rgds.

[Adam]

Thanks for the replies guys.
I bit the bullet and opened the module up. A bit scary as it was sealed. got it open and all seemed OK, a couple of areas were a bit cruddy but no corrosion. Cleaned carefully and put back together. Its still exactly the same unfortunately. I took some shots for you to see anyway just in case there was anything glaring that I didnt see .

Adam

[BENRUS]

HI Adam,
I recently reviewed your post here, and matched your module to this one of mine that is very similar

damdBatteries.JPG

broken.JPG

If it is of any use to you...Just let me know
Just trying to help.