# 1970'S Led



## ozzy (Dec 12, 2009)

Hello,

Thought I'd try and get some help from electric and electronic watches. I tried vintage watches and no luck so far I'm afraid.

I've got an old LED watch from the mid 1970's. It's got 'MERCURY TIME N.Y. USA' engraved on the back. It's also got 'ITALY' engraved on the locking clasp. The watch is gold in colour with a red face, and has a small fish scale effect all over. It has 1 button on the top right.

It takes 2 batteries but unfortunately it doesn't work. I took it to a couple of watch repair places where I live in the Midlands, but they just said it's too old and you cant get parts for these now. One suggested an electrician as it's an old LED watch, he also said the watch has all it's original parts.

I read some where that you can change the module inside the watch to one that works.

Does anyone know where or how I could get this watch working again. Any input very much appreciated.

Many thanks.


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## inskip75 (Jan 10, 2009)

Just wait for Silver Hawk to appear he's the man :yes: , by the way welcome to


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## Silver Hawk (Dec 2, 2003)

inskip75 said:


> Just wait for Silver Hawk to appear he's the man :yes: , by the way welcome to


Sorry...I'm hiding...I don't mess with LEDs / LCDs I'm afraid...the Devils's Work.


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## tomshep (Oct 2, 2008)

'avent done one of those for years...


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## inskip75 (Jan 10, 2009)

Silver Hawk said:


> inskip75 said:
> 
> 
> > Just wait for Silver Hawk to appear he's the man :yes: , by the way welcome to
> ...


Just shows my ignorance about the detail - I'll get my coat :sadwalk:


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## mel (Dec 6, 2006)

It's not usually a problem to change the module on these sorts of thing - it's sourcing the modules that's the problem. :yes:

A donor watch from the same timeframe might be a possible source - or very accurate measurements might source an "equivalent" module from current stocks - either way it's likely to be longer term than shorter. :to_become_senile:

You could try a gentle clean of all the contacts and exposed metal, espcially the battery contact strips (where the cell goes in ), that sometimes makes one spring to life - remember there's no moving parts in these except the pusher/contacts and the cell contacts.


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## Who. Me? (Jan 12, 2007)

Not wanting to force you to go elsewhere, but there are a few specialist LED and LCD forums on the web, in the UK and in the US in particular.

Given their 'specialist' nature (i.e. they're basically computers, rather than mechanical devices) you'll probably have better luck asking on a few of those forums.

At the very least, they could probably tell you where to find the module maker's name and model number on your watch, and which other watches shared that module, so you can find a donor.

Keep meaning to get myself a chunky '70s LED.

Sadly, the Omega Time Computer that I really want is out of my price range for a while.

Good luck.


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## JonW (Mar 23, 2005)

Ive recently had my Time Computer 2 repaired by a very handy chap in Germany, but not all modules can be repaired or replaced so be careful. I wore my TC3 for the first time yesterday... I felt very retro, LOL

For years people thought these and LCDs were awful, but get the right one and its great!


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## tomshep (Oct 2, 2008)

Does anybody have any duff ones for me to play with? I'm an electronics engineer. Thirty years ago when this stuff was cool, I understood this stuff pretty well. No promises, you'll get it back either way, but If I can make it work, I wouldn't mind having a go.

Many of these have poisoned or blown chips. You can't get them and that means that working LED watches are thin on the ground to the point of virtual extinction. That seems a shame to me.

You can occasionally get them going but you might have to throw a boxful away before you do.

The fragility of the circuits used in those days means that many may have been damaged by static or bad handling

Things to look out for: As has been suggested, battery corrosion. These things draw a comparatively high current when lit, several thousand times more than you need to spin a hummer. Batteries need to be good and fresh (and in plentiful supply!)

Keep the terminals as clean as anything else in a watch. The same goes for the switchgear. Close examination of the contact surfaces under magnification might disclose dirt or tarnish that may be stopping the switch from responding. Switches can also short and not release, locking the watch.

Displays: THese work by strobing each individual segment very fast, If a digit doesn't work then the digit driver in the chip may be faulty but if the break is due to a break in continuity,then it can usually be repaired, masking well and using silver loaded paint is a heat free way of doing it. It is rather a fiddle and conventional repairs with thin wires are more usual. Displays can be tested in situ, but they really are better lifted from the board which takes time, care and patience, in order to test them.

Mostly though it just plain won't work. That is when you need to start using an oscilloscope and start prodding around in earnest which is beyond the scope of this post.

The only replaceable part is usually the crystal. They are so cheap that it makes sense (only if a watch does not work,)to fit another and try your luck. A frozen watch with something up on the display might very well not be oscillating, so keep a few 32,768 Hz crystals around. Solder them only to the tips of the supplied wires when you try it, don't cut them to length yet, so if it doesn't work, you can save the crystal.


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## mel (Dec 6, 2006)

All good points from TomS. To clean the battery contacts and connections etc., I still use a self modified PCB cleaner Tom, one of the RS Fibreglass "pens" but with the tip wrapped in wire to keep it as tight as possible, and around 2mm dia - the rest tossed away - Devil May Care me! :lol:

Scoping one tends to be a bit of a black art, you need to know what it should look like on screen first, but, yes that could be done! (Mind you, I'd rather try it on a BIG one from an LED clock than from a watch :rofl: )


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## tomshep (Oct 2, 2008)

Ah but there's no fun in that. The genius, I'm sure within the LED watch is in the miniaturisation techniques imposed upon electronics. People were by this time quite familiar and completely wowed by the pocket calculator. They were on the lookout for the next amazing thing, and that was the digital watch. LED was out there on its own for some years before LCD became available. Everybody had one. They were cool, cheap and seldom tasteful, very rarely built to last and comparatively primitive by the standards of modern electronics. LCD engulfed the LED within two years and the LED watches themselves had vanished almost without trace two years later.

An LED clock works in exactly the same way and The scope signals to each display would be identical but with a watch, the difficulty lies in getting the signal off the board. A scope tip with an earthing sleeve close to the tip and short wires, possibly soldering wires to the crystal itself.


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## ozzy (Dec 12, 2009)

Thanks for the replies guys, very much appreciated.

Like (who.me?) suggested I've decided to go to a specialist LED site, still in communication but it seems to be going well, otherwise I may take you up on your offer (tomshep) of having a go at trying to get it to work, being an electronics engineer and all that, seems like it's your cup of tea.

Will keep you posted.

Cheers.


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## ozzy (Dec 12, 2009)




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## ozzy (Dec 12, 2009)

Thought I'd show you what the watch looks like from the front and back.


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