wittnauer repair?

[Seiko Kid]

I have the rectangular version I saw here in a recent post with a magazine advert - pics to follow

I have only managed to get 1 segment working for a brief period
by depressing a button, are there any tips or
methods with these modules to help get them working again?

Thanks

[charger105]

I think you'll have a Hughes module in there. The batteries need to contact the circuit board, the caseback, and a little tab that protrudes into one of the battery wells. Quite often this tab might not be making good contact. You could try bending it in a bit.

Otherwise, a new QC might be needed, which can be tricky on a Hughes. A new module is always a safe bet . They are very plentiful.

Rgds.

[Seiko Kid]

Hey Charger,

Thanks for the reply,

Yes it is a porcelain board with a plastic removable surround that houses the batteries. There is a metal tab that I presumed touched both batteries to create a 3v source? I assumed it is 3v for this module?

Is there a picture reference or particular method of how this tab sits?

Failing that could you point me in the direction of a new module

S. Kid

[charger105]

Hi Rob.
See below in the red circle:


Check this tab is making good contact.
I haven't got any Hughes modules lying around, but others may have. Failing that, look for a cheapo on Ebay that has the same button config. Quite often they have the double battery hatches too.

Rgds,
Andrew.

[Seiko Kid]

Hmmm, Now confused as I have more and less parts than you so I took some pictures

See here:

The watch -


The module -


The piece -
[/i]

[retroleds]

Couple things - first, Charger showed you a 25mm module, which only has one command button. Your's is a 29mm, which has two command buttons. But Charger is right about the small tab that points inward in the negative(down) hole. That side contact taps off 1.5 volts to keep the clock portion running when the display is off - the 3 v. is only used during display. So, watches that sit a lot will have two batteries of greatly different strength after several months.... If you tip the module over and the battery falls out of the hole with the side tab, it needs a gentle bend of the protruding corner. Your module may have pressed on contacts, which is a source of connection flaws - very easy to tab them down with a little solder.

The caseback is part of the circuit to ,again, tap off 1.5 volts to activate the display and setting functions. So the buttons won't work if there is not a connect from that [bridging] battery clip to the case/buttons.

The normal back for that piece has screw-in battery hatches, which(if not missing the springs on their underside) makes all the battery contact, so that bridging battery clip (taken off a Bulova ) is not needed.

One segment on a Hughes is generally not good news at all.

PM me for a replacement movement. OR go ebaying

[Seiko Kid]

ok, so the battery hatches do not have the springs attached .

I have 3 command buttons, the large 1 top right, 1 below that on the same side and 1 on the right hand side in the middle - however this last button does not make contact with the contact inside. I figured maybe bend out the ciruit board contact but the plastic case is in the way, there must be at least a 1 mm gap when the button is fully depressed?

I did what you said regarding the negative battery contact. The replacement LR44 batteries seem slightly slimmer than the holes and again the plastic is restricting me bending the contact enough to jam the batt in place, so I have used a thin piece of cardboard.

Now I fired it up and I get what you see below. The bottom line of digits are not working?




I also noticed that the contact for the middle button on the right side of the module has fractured at its base. But is still funcitoning

[bucko170]

Hmmm, Now confused as I have more and less parts than you so I took some pictures
The module -
[/i]

No trimmer! I know they have been shown here before but they must be quite rare?

[retroleds]

No trimmer! I know they have been shown here before but they must be quite rare?

HAHAHA! Good eye MIck - whilst focusing on the big picture I totally missed the missing trimmer. 'Twas early,

[Seiko Kid]

So guys who are wise in the way of LED watches, care to shed any light on the problems I have at hand here and how they can be resolved?

My options so far are to either :-

a. buy a replacement module from the mod

b. fix it , but from what I have learnt it may be a driver issue? is that common to all LED's or just the Pulsars?

c. What is with the trimmer situation, looks like 1 was never fitted so even if I do get the mod working, will it be incomplete?

[LEDluvr]

SeikoKId, I would go for option A. Hughes modules aren't expensive and you wont have to fuss with tracking down the problem.

[Kasper]

i've been following this all with interest...but tracking down the problem is part of the learning process.
If i bought a new module for every watch that didn't worked the first time, i would never learned all the ins and outs that i know now and i'm still learning
so option A is if everything else fails.

[Seiko Kid]

I understand you Kasper, but in all honesty the LED is just a curious move for me. My main interest is LCD where I am content with my knowlage and know my limits. I also am pretty confident that I know how to get most units up and running again or know if they are shot or not.

I have come across by random a few LED's recently but find that the module repairing part of watch collecting is too involved - I am an electrician which I do for my job everyday, I get involved with resistors and circuit boards but I have enough of this all day - it is the same with the LCD's. I dont mind a bit of soldering but after a while its gets boring.

I prefer case and glass work etc.

So, for my £10 wittnauer that I bought by chance I have to decide whats the best move as at present almost 30 LCD watches cover my bench awaiting repair. Same with the P4 that has already cost me £110 and doesnt work.

It is a very interesting side to the hobby LED reworking but it is not for me. I find what people are able to do on here
truly brilliant, just like you, using your trade to create crystals for your watches.

I just wanted to have a play with the LEDs , I think I will go for option A, and option A for my P4 - thing is I have a P2 on the way and I reckon that will be an option A too - Why is there never an option E? :)


Thank you all for your replies, I hope someday I can return some answers

[bucko170]

. What is with the trimmer situation, looks like 1 was never fitted so even if I do get the mod working, will it be incomplete?

Earlier post regarding 'trimmerless' Hughes module.
http://www.dwf.nu/viewtopic.php?t=2081& ... es+trimmer

[charger105]

Unfortunately if a segment is out on your Hughes, it will most likely be a broken wire bond. Only the early modules like Pulsars and Synchronars had discreet driver transistors for digits and segments. Very quickly these were all integrated into ICs (either a single IC for everything, or a display driver IC). Either way, it's all wire-bonded.

Repairing a wire bond on a Hughes module would not be economically viable unless you could do it yourself. I've never had any success doing a wire bond, but others have. You could give it a go, just for the experience, but be prepared to fail

Rgds.

[retroleds]

Well, based on the symptoms, at least it is only one wire bond - all those segments are being feed off the same display driver(yes, on IC), but it only involves one bond being broken, due to the magic of multi-plexing. You succes rate depends where the bond is broke - lot easier to fix at the trace than at the chip, if the wire-bond has merely lifted off the trace. Unless you have an actual bonding machine, in which case it might not matter. Piece-by-piece it is very time consuming....I usually wait until I have 5 or more that need wire-bond work, so i don't feel too crushed by the spotty success rate.