Starting a 7t27/ym57a - chrono fine, watch not

[tIB]

Hi, hopefully someone here can help as I'm a bit stumped...

So I recently acquired a non running RAF gen2, which when it arrived had the chronograph section working fine but not the watch function - the bottom seconds dial wasn't running and the hour/minute hands didn't run. New movement I thought...

Well I've fitted a new ym57 tonight after tracking one down - I have exactly the same issue: chronograph functions fine, watch part isn't running. 

I've read the tech sheet and understand there's a circuit reset - I've tried that with various things but nothing happens: the watch remains stopped with the second hand subdial not turning. 

Any ideas? I've the same issue with both movements which makes me think I've missed a step somewhere, though can't find anything else in the technical sheet? The YM57a is nos from a reputable seller so assume all is fine there. Help?! 

 

 

 

 

[AndyGSi]

I'll see what info I've got tomorrow that may help but in the mean time can you confirm what battery you've fitted and what you've done to reset.

[tIB]

5 hours ago, AndyGSi said:

I'll see what info I've got tomorrow that may help but in the mean time can you confirm what battery you've fitted and what you've done to reset.

Thanks, appreciated! I've tried to reset by shorting the AC point on the movement back to the battery - I've tried various things but it doesn't seem to wake it up.

 

Battery wise I replaced the one it came with with a Renata 395 - had the same issue with both batteries (and movements). As I said the chrono part is working as should, it's just that the clock part isn't...

 

Thinking about it I haven't checked the fitting on that seconds hand on the subdial - I guess that could be fitted too close to the face and having that same issue could just be coincidence... I'll try this evening and update, meanwhile thanks again!

[xyzzy]

The Chrono function and the time use different coils.  Check the resistance, carefully, to see if the time keeping coil is damaged.  Should be in the service manual, probably about 2.4kΩ.

Make sure the crown is in and the position sensor is touching the circuit board in proper location.

[tIB]

14 minutes ago, xyzzy said:

The Chrono function and the time use different coils.  Check the resistance, carefully, to see if the time keeping coil is damaged.  Should be in the service manual, probably about 2.4kΩ.

Make sure the crown is in and the position sensor is touching the circuit board in proper location.

Ooh on the crown - that's definitely one to try and I have another here that came with the new movement... I've used the same on both movements so far, so perhaps somehow the culprit? 

 

Coil wise I'll have a play after trying that - thanks for the help! 

[watchweasol]

Hi when resetting the movement did you try the ac point to the main cover or coil cover, on the T series there are procedures required in setting up the stop watch and others did you do all that

7T24A_34A_36A_44A.pdf

[AndyGSi]

These can also be reset by pulling the crown to the second position
and pressing both chrono buttons together for 10 seconds.

[tIB]

1 hour ago, watchweasol said:

Hi when resetting the movement did you try the ac point to the main cover or coil cover, on the T series there are procedures required in setting up the stop watch and others did you do all that

7T24A_34A_36A_44A.pdf 647.22 kB · 0 downloads

I've only shorted to the battery itself - I'll try the covers tonight...

 

I've set up the stopwatch as per the instructions, and I did try holding both buttons in but will try again tonight...

 

Thanks all - I'm really hoping it's the crown but we'll see...

[tIB]

What's interesting about the crown thing is that I had that second hand subdial running very briefly in the original movement, like a second or two, before it would stop again - wonder if that brief sign of life when the crown was first pushed in signifies a poor connection? I used the same crown on the replacement movement so with any luck the one that came with it will work when I try later...

Does the crown itself connect to a position sensor?

[AndyGSi]

Is the crown fully engaging with the case tube or is there some debris in the crown preventing this?

You may want to try it out of the case with no restrictions.

[tIB]

35 minutes ago, AndyGSi said:

Is the crown fully engaging with the case tube or is there some debris in the crown preventing this?

You may want to try it out of the case with no restrictions.

I have tried it uncased and it seems to be engaging fine, in that the stem removal dimple goes into the positions youd expect it to be at (with both movements). 

 

Thanks for the help all btw - appreciated!

[tIB]

Well nothing is simple here - the crown that came with the NoS replacement movement (which is actually doing the same as the movement it replaced!) doesn't appear to fit either the new movement or the old one! Odd. 

Had another go at the reset procedure listed on the sheet posted below - still nothing. Tried the hold for 10 seconds thing too - same.  

Need to read up on testing the coils, though it would seem unlikely (would it?) that both the original movement and it's new replacement have exactly the same issue. 

Don't have much time tonight, but my dream of switching out the movement for a new one to achieve a working watch seems quite a bit more complicated than I imagined! 

 

Attached is the tech sheet for the replacement movement, which is identical to the original. 

Y187A.pdf

[AndyGSi]

Question I should have asked earlier, is it just the small second hand that's not moving and the minute hand works as expected?

I'm beginning to think that even with the NOS movement it's seized with old lubricants.

[tIB]

3 minutes ago, AndyGSi said:

Question I should have asked earlier, is it just the small second hand that's not moving and the minute hand works as expected?

I'm beginning to think that even with the NOS movement it's seized with old lubricants.

Neither the small second hand or hour/minute show any sign of life - the chrono sweep second and minute counter works fine, as does the hour subdial in relation to the hour hand when turned manually. 

Wonder if it's worth me asking the seller, though they're over in the states so returns probably aren't feasible. I'm probably not skilled enough to disassemble it unfortunately. 

It's a headache...

[AndyGSi]

I( can't remember on these if you can see the rear pivots.

If you can then a quick test is put a drop of IPA and a blip on a quartz tester / demagnetizer and if it works then a drop of fresh oil.

If you can't see the rear pivots then even a blip on a quartz tester / demagnetizer could free it.

[tIB]

1 hour ago, AndyGSi said:

I( can't remember on these if you can see the rear pivots.

If you can then a quick test is put a drop of IPA and a blip on a quartz tester / demagnetizer and if it works then a drop of fresh oil.

If you can't see the rear pivots then even a blip on a quartz tester / demagnetizer could free it.

Well... it's only gone and started! Couldn't tell you what I did, came home late from work thing and decided to offer gentle persuasion... turned it around to get the movement out and noticed it ticking, result! 

Thanks all for the help, particularly you Andy - as a noob here it's been the nicest possible welcome to a forum I could hope for: so helpful! 

To the strap draw!

 

 

Pleased with this one - as a fairly new convert to fixer uppers I've learned how to refurbish and relume (badly!) hands, I've switched the movement over including date wheel swap and rear plate, fitted the tiny hands for the first time and done my first non acrylic crystal swap. Here's how it arrived:

Might have a play with diamond polish on the original crystal at some point... Need a rear gasket and strap too... 

[tIB]

Ah so I'm not completely sorted yet - woke up to find it stuck at 12 midnight. The date had changed though I'm wondering if it's calendar wheel related or possibly those relumed hands catching... Moved it past twelve o'clock and everything restarting fine and it's happily ticking now. 

 

I'll wear it today and see what happens, though if anyone has a suggestion I'm all ears. 

[AndyGSi]

If it hadn't changed date then I would have thought that was the problem but as it did I suspect it is the hands catching.

Do you know the pinion heights of the old and new movements?

Edited July 17, 2024 by AndyGSi

[tIB]

1 hour ago, AndyGSi said:

If it hadn't changed date then I would have thought that was the problem but as it did I suspect it is the hands catching.

Do you know the pinion heights of the old and new movements?

Believe they're exactly the same, though the difference will be my heavy handed reluming... I'll see what happens at 12 pm today and go from there...

I do have some hands that are very similar - I could try those though probably would be better reluming again as it was my first attempt.

[tIB]

Odd one... Twelve o'clock came and passed without issue. I wound forward so it would pass 12am too - date change fine, didn't stop... One to keep an eye on I guess?

[AndyGSi]

Maybe it's just settling in!!!

[tIB]

3 hours ago, AndyGSi said:

Maybe it's just settling in!!!

I certainly am - every time I look at it I think it's stopped working again as I keep forgetting the seconds tick on the subdial only! 

[tIB]

Well it's kept ticking fine - since I wasn't happy with the lume on the hands and I was suspicious it caused that stoppage I decided to bite the bullet and relume... went a bit thinner on the mix and spread on lighter with the correct (ish - used an oiler) tool. Happier with the results and hoping that it keeps ticking...

[tIB]

Got some oddness here on the hour subdial - I've read it between one and four hours out at different times. Wondering if it's catching somewhere? Any other possibilities?

 

Other than that it's all good - might have a go at cleaning up the OG crystal and will have a think on that hour hand. 

[AndyGSi]

If you see the hands stick as they pass then that's more then likely the problem.

Otherwise it could be the movement that's seizing.