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Fixing a broken coil wire

15K views 26 replies 10 participants last post by  BenchGuy 
#1 ·
A chap at work asked me to change the battery in his wifes watch that had been dead in a drawer for some years.

The press back was easy to remove with a case knife, but whoever had been in there before obviously used the wrong tool




and not only had they marked the case, but I'm certain they damaged the coil at the same time




you can just make out the wire (bent towards the right) that should be attached at the left.

So, has anyone had any success fixing a coil wire that has been snapped at the point it would normally attach?

The only thing I can think of involves a soldering iron but I'm not sure if the heat will melt the wire?
 
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#6 ·
Grobet Circuit maker will do this job just fine. Product is made by Permatex and a similar product is available at auto supply vendors...used to repair contacts in heating elements in glass. You paint it on, let it dry and you are done. Soft solder is likely to make you very sad...
Regards, BG
 
#7 ·
As I said above, I've decided to buy a new movement (only £12) but for future reference could you explain how this product would work in the situation I've got.

The wire has been broken at the point it joints the PCB. There is no slack in the wire.

The circuit has some kind of resin over the pad where the wire needs to connect. I guess I would carefully scrape the resin off without removing the gold contact.

I assume the copper wire has some coating on it - does this need scraping off?

Then do I just paint the 'Circuit Maker' onto the pad and also on the end of the wire and then just push the wire towards the pad and when it dries it completes the circuit?
 
#8 · (Edited)
That product made by ...Permatex is used on electrical parts in Automotive shops. Alternator and Generator shop use it also. It can be used on Ignitions, and also Starters and all kinds of products. It is conductive and will allow the power current to work. After you use it you can coat it with
The Varnish or Shellac coatings also. Many use it for Remote Control Model making and it is very popular with the kids in making those robots for competition.
It can be used for Computer repairs, Radios, and a whole lot of other uses.
Also make sure you clean the end of the wire of the coating, but also make sure it is not.....
( Exposed Bare after it is done in any area to drain power or cause a short. )
 
#9 ·
Place the wire back close to the point of breakage. Put join the points with a drop of circuit mender. The material will conduct from break point to break point (which will have no coating). Material also will repair most superficial coil damage (ie. slipped screwdriver)...it will not repair internal damage or corrosive damage. I've used acetone or OneDip as a solvent to thin, if necessary. Regards, BG
 
#16 ·
Yep - the movement caliber is there:




but it was hidden by the dial spacer, and not having worked on one of these before I didn't find it until after I'd ordered!!

I did think about unwrapping one turn, once I'd removed the circuit and coil, but the varnish that the coil is painted with has effectively glued the strands in place and I think if I tried to separate the strand it would probably snap off.

So, for now I'm going for the repair option.
 
#18 ·
Was the movement you ordered a 955.xxx instead of a 956.xxx? They look pretty similar.

If the repair doesn't work I'm pretty sure I still have some good 956 circuits in stock but, as Riley says, unless you're confident about the mechanical side (or your ability to service it), a complete movement swap is probably the best bet.
 
#19 ·
I ordered a 956.412. It looked very similar, but of course when it arrived and I compared them like for like there were subtle differences that I really should have spotted.

I'm very confident that if I needed to I could service the movement. But, it looks pretty clean so I'm hoping it will work correctly once I can get power to the coil.

If it doesn't I might be interested in a circuit if you have the correct one.

Thanks.
 
#24 ·
A chap at work asked me to change the battery in his wifes watch that had been dead in a drawer for some years.

The press back was easy to remove with a case knife, but whoever had been in there before obviously used the wrong tool




and not only had they marked the case, but I'm certain they damaged the coil at the same time




you can just make out the wire (bent towards the right) that should be attached at the left.

So, has anyone had any success fixing a coil wire that has been snapped at the point it would normally attach?

The only thing I can think of involves a soldering iron but I'm not sure if the heat will melt the wire?
I am a big believer in trying to fix things. In many cases these days the parts are avalible and cheap so repairing things has become a lost art. We now live in a disposable world.
I often have wondered as I have many older Seiko quartz watches that do not run for the want of an obsolete coil. Has anyone ever been crazy enough to try and rewrap a coil? I know of a good source of this fine copper wire. It is very common and used in just about every car for the sensors for the camshaft and crankshaft and also used for the wheel speed sensors. If you can get your hands on a defective one and break off the plastic housing you will find a magnet wrap in a huge amount if this fine stand copper wire. It is about the width of a human hair. I still have a bundle of it I saved.
If the fisherman that make their own fishing fly bait it should be possible to rewrap the coil and use the heater element repair kit to secure each wire at both ends. You would know if you got it right by putting the test leads on it and checking the ohms to see if it fell within specs.
Maybe one day when I dig myself out of the pile of watches I have to repair I will have a go at it.

Michael
 
#25 · (Edited)
I bought some conductive (silver) paint and had a go at a repair, but I'm disappointed to say it wasn't successful :(

I got the tip of the wire to make contact with the tiny blob of paint that I applied to the circuit contact point, I then put super glue on top to strengthen / seal it.




But, popping a battery in resulted in naught.

I did strip the movement to check that all was ok in the gear train, but apart from a slightly dirty stator (which I cleaned) it all looked very good.

Not having seen the watch working, or knowing when it last worked its not really clear what the problem(s) might be.

So, I've ordered the correct movement from Cousins (about £30) and will fit this.
 
#27 ·
I bought some conductive (silver) paint and had a go at a repair, but I'm disappointed to say it wasn't successful :(

I got the tip of the wire to make contact with the tiny blob of paint that I applied to the circuit contact point, I then put super glue on top to strengthen / seal it.

But, popping a battery in resulted in naught.

I did strip the movement to check that all was ok in the gear train, but apart from a slightly dirty stator (which I cleaned) it all looked very good.

Not having seen the watch working, or knowing when it last worked its not really clear what the problem(s) might be.

So, I've ordered the correct movement from Cousins (about £30) and will fit this.
What was the resistance across the coil after the silver paint and before the superglue?
I've never used the silver paint, only the Vigor Circuit Mender...this has only failed on coils with internal (not surface) issues.

Regards, BG
 
#26 ·
With me it is the curiosity of is it possible to make a working coil by starting with a known bad coil stripping of the bad wrapping and rewinding it with new copper. The most common coil failure I come across is open circuit which is when you touch the leads to both contact points and get all zero's on the meter.
I don't think I have come across a shorted coil yet on a Seiko. Typically these situation will give you ohm readings on the high side and out of specs.
One day I will have a go at it as unless I try it this question will always bother me.

Michael
 
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