Seiko 6R15C suddenly losing time

[Mechanicmosco]

Hi all,

First of all I would like to say I am new to the forum. I have been working on watches for quite some time now but this one has me stumped (mostly because it's my newest, least touched watch!).

A little bit of backstory. This watch is about 2 years old, I purchased it new (Seiko SARB033). It ran fantastically, i got it down to +2 seconds a day and it was a very consistent watch. About a month ago it started losing time. Badly, around 1-2 minutes a day. I initially thought the regulator might have slipped out of position so i adjusted it up. But it still ran poorly, gaining massive amounts and then losing massive amounts. So, I put it on the timegrapher i recently purchased and found this. Does not look good. Can't get amplitude above 180 and there is a strange drop off on the lower line that comes around regularly. I demagnetized the watch and the balance separately, but to no avail. Beat error was also horrible (around 2.5ms), but i've adjusted that down a bit just so it could be read easier. 

 

What do you think guys? Escapement fault? Gear train? Slipping mainspring?

[clockboy]

It could be magnetised which will make the watch run erratically because the hairspring coils will stick to each other & you will also get a low amplitude. The other issue could be a damaged hairspring caused by a slip when adjusting the regulator. Being only two years old I have my doubts it needs a service unless some dirt/grease has got into the hairspring. Good magnification will be most useful with this.

[jdm]

Most likely is a (distorted) HS issue, bent staff pivots, or even endshake. You can try replacing the balance complete, as it's quite affordable.

[Mechanicmosco]

I have demagnetized the watch completely. I've removed the balanced and demagnetized it as well on its' own, and honestly the hairspring looks decent but I did notice the coils are a little closer to each other on one side than the other.

Could that be causing this? I'm just not sure because the weird erratic beating happens regularly, as if it was a train issue.

[jdm]

1 minute ago, Mechanicmosco said:

Could that be causing this? I'm just not sure because the weird erratic beating happens regularly, as if it was a train issue.

Try poking gently the regulator arms from below and check in amplitude changes. Possibly an escape wheel / pallet fork issue. The approach most often recommended is to examine all parts under the microscope. But in practice replacing key parts with new / known good ones could be more expeditious.

[Mechanicmosco]

Had a look at everything under good magnification. The hairspring is off center, coils are much tighter on one side. Tried tweaking it a little bit but couldn't get it perfect. Graph looks better but still not good.

51 minutes ago, jdm said:

Try poking gently the regulator arms from below and check in amplitude changes. Possibly an escape wheel / pallet fork issue. The approach most often recommended is to examine all parts under the microscope. But in practice replacing key parts with new / known good ones could be more expeditious.

Tried doing this, no change in amplitude. Rate increased, but no significant amplitude increase. I will order a new balance assembly and see where that gets me.

 

[jdm]

1 hour ago, Mechanicmosco said:

Had a look at everything under good magnification. The hairspring is off center, coils are much tighter on one side. Tried tweaking it a little bit but couldn't get it perfect. Graph looks better but still not good.

Tried doing this, no change in amplitude. Rate increased, but no significant amplitude increase. I will order a new balance assembly and see where that gets me.

Have you looked at pallet pivots and stones? 170 deg amplitude is too much drop, even for a Seiko off-centered HS.

[clockboy]

If it is not magnetised then it has been damaged/missaped in some way. There are vids on youtube showing how to manipulate the hairspring.The most common fault is the end curve of the hairspring gets misshaped when regulating which in effect moves the hairspring out of centre. Here is a good demonstration of this effect & how to correct.I use this method apart from straightening the spring first as I see no point in doing this. But everyone to their own method as hairspring manipulation takes practice & patience.  

 

 

[Geo]

I hope you havn't caused more damage by bending the hair spring. Have a read of this, it may help.

 

[Mechanicmosco]

I have straightened the hairspring as well as I could. It is not damaged and honestly, amplitude looks a bit better. But crucially, the watch has that periodic fault that keeps coming back so I think that the HS is not the primary culprit here. I will report back once I've stripped the movement back and gotten to the pallets and escapement wheel, as I think the frequency at which the problem comes around indicates a wheel issue.

This post matches my rate and amplitude issues, but here he has no timing fault like my timegrapher indicates. 

12 hours ago, Geo said:

I hope you havn't caused more damage by bending the hair spring. Have a read of this, it may help.

 

[jdm]

By coincidence, I have been working the best part of this afternoon on a 7S26 with virtually identically symptoms: reduced amplitude, in my case 185 deg. at best.

Watch is quite recent, Nov. '12.
Demagnetized, redone balance jewels lubrication. HS shape, pallet fork, all checks OK under the loupe.
Beat error, positional error are good.
Balance cock screw was found loose, but after tightening problem remains.
Blowing air on the balance gets amplitude to 220, even 250 deg.s but just for few seconds, after which it returns as above.

In the end life is too short to deal with stubborn mysteries and since the watch  must go tomorrow I've replaced mov.t complete with a good one. 

 

 

Edited April 17, 2017 by jdm

[clockboy]

From experience I have found, and stated before on the forum Seiko,s tend to have a low amplitude for some reason. Getting 250 deg,s is good for a Seiko and they run just fine. 

[jdm]

From experience I have found, and stated before on the forum Seiko,s tend to have a low amplitude for some reason. Getting 250 deg,s is good for a Seiko and they run just fine. 

Correct, but the issue at hand here is that the OP one has 165 deg.s and mine 185. Not enough, otherwise we wouldn't be here talking about it.

[clockboy]

I was pointing out the fact that when the issue has been resolved a 250 deg amplitude is acceptable for a Seiko. I personally would not leave it alone until the issue was resolved.

[mikepilk]

I just had similar problems on an Omega 1012. After cleaning the amplitude suddenly dropped from about 250 to about 180 with a lot of noise on the lower line on the timer (and the beat error jumping all over the place) . I stripped it all again to put all the parts under the microscope, but a bit of thought could have led to the problem (I should have posted it here) : The exit pallet stone was loose. 

Edited April 18, 2017 by mikepilk

[digginstony]

The watch is only a couple of years old. It's a very good quality Seiko movement. True Japanese tend to have a lower amplitude than there Swiss counterpart but the amplitude, face up/down should be around 260 dropping to around 240 in different positions. It could be a loose stone. Slightly bent pivot. Damaged jewel. Timing of the stones to the escapement wheel. Might even be, the hairspring has worked slightly loose on the balance staff.
It's pointless undertaking further investigation if the hs is not centred. So I agree with Jdm, replace the balance wheel assembly.

Sent from my SM-T585 using Tapatalk

[Mechanicmosco]

Hi everyone,

Finally had the chance to get the pallets and escapement out. Everything looked fine. So i cleaned it up, lubricated, reassembled and behold! No more escapement fault! Stronger amplitude too! So to be honest i'm not sure exactly what was wrong, likely some contaminant in the escapement. Watch sounds much better too.

3 hours ago, digginstony said:

The watch is only a couple of years old. It's a very good quality Seiko movement. True Japanese tend to have a lower amplitude than there Swiss counterpart but the amplitude, face up/down should be around 260 dropping to around 240 in different positions. It could be a loose stone. Slightly bent pivot. Damaged jewel. Timing of the stones to the escapement wheel. Might even be, the hairspring has worked slightly loose on the balance staff.
It's pointless undertaking further investigation if the hs is not centred. So I agree with Jdm, replace the balance wheel assembly.

Sent from my SM-T585 using Tapatalk
 

The amplitude is still not where I want it, but I have a new balance assembly on the way and I'll keep you guys updated to see how that improves things!

 

 

[Mechanicmosco]

Ok just to update you guys:

I have replaced the whole balance assembly. Bought a spare NE15 movement and swapped it completely including the bridge....

 

Exact same results as I have shown above. Poor amplitude (215 deg max), time loss and variance.

I am going to swap the escapement pallets and wheel from the new movement and hopefully that will help.

[jdm]

Why taking parts from a new mov.t? New parts are available from Cousins. 215 deg. is kind of acceptable for a Seiko 7S or 6R. Large positional help which can't be corrected with the usual means is also quite common.

 

 

 

[Mechanicmosco]

Changed the escapement wheel and pallets now. 240 degrees and much better accuracy. Although it still isn't nearly as good as it once was (which perplexes me), I'll consider it acceptable.

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[Mechanicmosco]

Nope; but it on the grapher and I'm getting wavy lines, for a while it's -30, then -96, then back up, and all over the place. It's already lost 10 seconds in two hours.

Very frustrated with this watch, considering replacing the entire movement since I did buy an entire spare.

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[mikepilk]

I've just finished cleaning a 7002A, and with a new mainspring gives 215 - 240. My 7S26 gives similar figures. I consider 220 OK for a seiko and 240 as good. 

[digginstony]

Nope; but it on the grapher and I'm getting wavy lines, for a while it's -30, then -96, then back up, and all over the place. It's already lost 10 seconds in two hours.

Very frustrated with this watch, considering replacing the entire movement since I did buy an entire spare.

Sent from my SM-G930W8 using Tapatalk

If the fault isn't in the escapement and it's not magnetised you have a bent pivot or damaged jewel somewhere. Or accelerated wear for some reason. If you're not undertaking the work as part of a learning process, personally I would take Jdm's advice earlier in the thread and swap the movement "Life's too short"
What I can't understand is when you replaced the balance and all was good and then it went bad again ?

Sent from my SM-T585 using Tapatalk

[clockboy]

it only takes the smallest of faults to slow or stop a watch. Working on a diver style watch last week & it ran absolutely great for approx 40/50 seconds & then stopped. After the usual checks I had to strip the watch again and I found the top of the seconds pivot was bent which was causing the sweep seconds to bind just enough to stop the watch.

It can be frustrating at times horology but a real nice feeling when you actually find the fault.

[Mechanicmosco]

Yes, you're right. It is frustrating but nothing is quite as rewarding as getting these one running well!

On ‎2017‎-‎05‎-‎11 at 10:09 AM, digginstony said:

If the fault isn't in the escapement and it's not magnetised you have a bent pivot or damaged jewel somewhere. Or accelerated wear for some reason. If you're not undertaking the work as part of a learning process, personally I would take Jdm's advice earlier in the thread and swap the movement "Life's too short"
What I can't understand is when you replaced the balance and all was good and then it went bad again ?

Sent from my SM-T585 using Tapatalk
 

So I cleaned and lubricated the escapement wheel and pallets. That cleared up the weird fault and beat error. Then I replaced the balance, but amplitude still was not great. So then I replaced pallets and escapement wheel. Better; but still not consistent and nowhere near what I feel this movement is capable of.