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Requesting help with a Citizen Promaster Dive Watch - broken stem and dead capacitor

BarryG
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BarryG New Member

BarryG

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A friend gave me a 2012 Citizen Model B740 Promaster dive watch which doesn't run and has a broken stem (part no. 069-9930), so I decided to try and fix it.  I don't remember ever fixing a watch like this or any watch but for some reason I had a set of tools.

I opened the watch up and removed the capacitor.  The voltage on the capacitor was 1.2 V instead of 1.5V.

With some help from a local watchmaker, I removed the broken stem.   I now have the crown, the stem and a small section of either a threaded rod or a stiff spring.   I checked with Citizen USA and the stem is no longer available (at least in the US).  So I have a couple of questions:

Is the capacitor dead?   Can I recharge it?    I can buy a replacement for about $20.

Is the anywhere in the world where I might be able to get a replacement stem?

Is there any way to repair the stem?  I doubt that would be easy.  How do they make these stems in the first place?

Online I see stems for sale that look similar to 069-9930 and are also 21mm long and start with part no. 065-xxxx.   Is there any chance that one of these stems would work or at least would get the watch running?  I obviously don't care if the watch ever sees the ocean again.

When do watchmakers and amateur watchmakers throw in the towel?

Thanks

Barry

 

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Marc Distinguished Member

Marc

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2 hours ago, BarryG said:

Is there any way to repair the stem?

If there is still some thread (a couple of mm) on the part of the stem that goes into the watch then you could use a stem extender, which does exactly what its name suggests.

https://www.cousinsuk.com/category/stem-extensions

You will have to either get a new crown or recover the original, and you will need to cut the extended stem to length.

2 hours ago, BarryG said:

When do watchmakers and amateur watchmakers throw in the towel?

Professionals, usually when it becomes uneconomical to proceed unless they have some other motivation to keep going.

Amateurs, it depends on the severity of their affliction but at its worst, never..... and it's incredibly infuriating!!!!!!  🤣🤣🤣

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HectorLooi Distinguished Member

HectorLooi

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Eco drive watches do not use a true capacitor anymore. The "capacitor" is actually a rechargeable battery. If the old battery still reads 1.2V, then there is hope that it's still ok. 

The next question is whether the photocell is working? Can the watch charge up the battery? 

Then the next question is whether the movement is functioning properly? 

The winding stem is not a big problem. A competent watchmaker should be able to fabricate one easily. 

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Nucejoe Distinguished Member

Nucejoe

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Did you try to let the watch charge its battery?   Solar cells wont last for ever, you might find the watch fail  to charge the new battery. 

You should investigate if a stem extender wont catch onto any part, such as  movement itself, stem tube, ring etc. 

Rgds

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BarryG New Member

BarryG

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Wow - I was pleasantly surprised at the quality and quantity of the responses to my post.    I will try some of these suggestions.  I have attached photos of the crown and stem as I found them.  Would a stem extender work?

I am going to try to charge the battery/capacitor back to 1.5 volts, and I will report back

Thanks to all. 

20230211_074118.jpg

20230211_074304.jpg

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BarryG New Member

BarryG

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20 hours ago, HectorLooi said:

The photos are a bit blurry but does the end of the stem have a threaded hole?

I've never seen a stem like that. If indeed it has a threaded hole, does that short bit of stem screw back into the hole?

Wow - I was pleasantly surprised at the quality and quantity of the responses to my post.    I will try some of these suggestions.  I have attached photos of the crown and stem as I found them.  Would a stem extender work?

I am going to try to charge the battery/capacitor back to 1.5 volts, and I will report back

Thanks to all. 

As best I can tell with a magnifying glass there are no threads in the hole.   (I may take a look with a microscope if I can find it).   I tried to screw in the short piece of stem without any success.   I was thinking, I could solder the short-threaded piece into the hole, but that probably would not work.  There must be something missing but it looked like everything I had added up to 21mm which seemed to be close to the correct length.

I also cannot figure out how a stem extender (an earlier suggestion) might work, but I might order some and give it a try.   It is clear that none of this makes economic sense, but that is why this is a hobby.

I was also looking a some replacement Citizen stems (not meant for diver watches) which looked similar and were also about 21 mm in length.  I just want to see if I can get the watch running, and if I can I can set the time once (twice)  a day with the battery.

Do these batteries have an extra tab on them to make better contact?

Thanks

Barry

I noticed that there is an o-ring on the stem.  Is it possible that the two parts of the stem on either side of the o-ring can be unscrewed or is there just an indentation in the stem to fit the o-ring?

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Nucejoe Distinguished Member

Nucejoe

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 In case you can't find a new stem to buy, you can solder a piece ( all thread ) of another ( broken stem ) into the hole of this one and  make a long stem. The problem you might have is the two pieces soldered together might not make a streight stem, in which case melt and try again . 

Good luck pal.

 

 

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watchweasol Distinguished Member

watchweasol

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Hi Barry the O ring on the stem is for waterproofing ,  You can use a 1,55v cell in the watch to checkout its functions but obviously wont charge up but it will provide the voltage to drive the watch.  The stem according to the tech sheet attached to your previous answer designates it as a one piece construction,

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