# Precision of Seiko 8f movements



## warrenn (Jan 15, 2010)

I was wondering about the experiences of others who have purchased Seiko watches with the 8f movements (8f32, 8f33, 8f56, etc.) with regard to precision. I am on my second 8f watch and the errors of both are much greater than the advertised +/-20 second per year maximum error. Although these movements seem to be on the way out in the American market (they are readily available elsewhere), they are a very inexpensive way to obtain higher precision than the usual uncompensated 32 kHz movements (both of my watches cost well under $200).

I purchased my first about 7 years ago (an 8f33) and it has been consistently fast by 0.2 seconds per day (73 seconds a year). This is a constant drift - the random component is much smaller. In fact, the random error would be well within the advertised error if one corrected for drift (which is not what I want to do). Unfortunately, these watches don't seem to have an internal adjustment for drift (trimmer capacitor across the crystal?).

My first 8f watch was returned to the factory twice - on the second return, they claimed to have replaced the movement. Unfortunately, the "new" movement had exactly the same drift, which makes me a little dubious of their claim.

I recently received (for Christmas) an SLT079, which has an 8f56 movement. The watch is very nice, though it is a little heavy (stainless case). So far, the drift is 0.14 seconds per day. If my experience is any guide, this drift will be constant and the yearly error will be 51 seconds. 

This second watch also has some problem with the hand alignment - the GMT hand and hour hand are not exactly aligned with the hour markers on the hour. This is mainly aesthetic (though the alignment error in the GMT hand could cause reading errors). 

Both movements were made in Japan, as stated on the face and back of the watches. Also, both watches have been worn the requisite 12 hours per day.

Cheers,

Warren Nagourney


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## Hans Moleman (Sep 24, 2007)

I don't have a 8F movement, so I can't comment on them.
But did you see this thread?
https://www.watchuseek.com/showthread.php?t=272143
Dwjquest posted the second graph where a ordinary movement is compared to a 8F56 movement in their ability to handle temperature changes.

It shows in my opinion that a 8F56 movement copes with temperature changes twice as good as an ordinary movement.

The random component in your measurements is in my opinion most certainly temperature. Even when worn for 12 hours there is lots of scope for 'randomness' left especially when temperature compensation isn't that advanced.

You're talking about calibration. 
And by the stories I hear on this forum, I would bite the bullet and do it myself.
Warranty is all very good, but ineffective warranty is useless.

Search for 'pattern cutting' in this forum. And do your homework very well since it is irreversible.


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## warrenn (Jan 15, 2010)

Thanks. I found a manual which describes the pattern cutting procedure for my 8f33. It will remove about 1/3 of the error. I might let a jeweler do it if they don't charge too much. It will take off 64 ms from my 200 ms daily gain. The 8f33 watch is well out of warrantee (by 5 years or so).


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## webvan (Dec 11, 2008)

Can you share a link to that manual, always been intrigued by the "pattern cutting" process !


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## Hans Moleman (Sep 24, 2007)

Good luck!
Just make sure you've taken control of that temperature.
It still is the biggest spoiler.
Establish the rate at the temperature you want to use it with, and then make your correction.
Don't make my mistake: Regulate at (a fluctuating) room temperature and then start wearing it. That's a waste of time.


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## dwjquest (Jul 22, 2006)

Hans Moleman said:


> I don't have a 8F movement, so I can't comment on them.
> But did you see this thread?
> https://www.watchuseek.com/showthread.php?t=272143
> Dwjquest posted the second graph where a ordinary movement is compared to a 8F56 movement in their ability to handle temperature changes.
> ...


Here is a better graph of a Seiko 8F movement compared to a typical non-thermocompensated movement. In this case the Seiko movement was an 8F35.

The two curves did not originally fall at zero rate in the same spot, so I shifted the curves so that both curves had a zero rate at about 76 deg. F. This did not in any way change the shape of the curves, but the comparison of the temperature effects is easier to see.


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## warrenn (Jan 15, 2010)

Here is the link to what looks like a service manual for the 8f movements (except for the 8f56). Ooops, doesn't work. I found it by Googling "seiko 8f pattern cutting" and it is the first response - a pdf file beginning in "4F/8F PDF" and then some Japanese characters.

Cheers,

Warren Nagourney


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## webvan (Dec 11, 2008)

Thanks, that's interesting, not much adjustment is possible though and even after looking at the drawings, I'm not quite clear what a "pattern" looks like exactly ;-)


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## Hans Moleman (Sep 24, 2007)

webvan said:


> Thanks, that's interesting, not much adjustment is possible though and even after looking at the drawings, I'm not quite clear what a "pattern" looks like exactly ;-)












From the PDF at:http://www.pmwf.com/Watches/Seiko/4F32A%2C8F32A%2C33A%2C35A.pdf

It looks like the wire runs over a small indentation, so that you can grab it. Or push down with a needle I guess.


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## pmbirner (Sep 20, 2009)

I know this far from a scientific analysis but perhaps its something to add to the overall database and concern posted by warrenn. I just checked my wife's Seiko Perpetual Calendar with the 4F movement in it. I set it around a week before I gave it to her this past Christmas. Almost a month later its running 3 seconds fast. She likes her watch (hurray!) which means she's been wearing it for more than the requisite 12 hours a day to have more of a chance of attaining the 20 seconds per year mark. Where we live I'd have to say the average temperature has been around 75 degrees with no real extreems in temperature one way or the other. So I'm thinking her watch is running 40 seconds a year fast--around twice as fast as its spec states. 
Phil


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## Catalin (Jan 2, 2009)

pmbirner said:


> I know this far from a scientific analysis but perhaps its something to add to the overall database and concern posted by warrenn. I just checked my wife's Seiko Perpetual Calendar with the 4F movement in it. I set it around a week before I gave it to her this past Christmas. Almost a month later its running 3 seconds fast. She likes her watch (hurray!) which means she's been wearing it for more than the requisite 12 hours a day to have more of a chance of attaining the 20 seconds per year mark. Where we live I'd have to say the average temperature has been around 75 degrees with no real extreems in temperature one way or the other. So I'm thinking her watch is running 40 seconds a year fast--around twice as fast as its spec states.
> Phil


Is that one of the older or US-made models or one of the JP-only models ?


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## Sideshow_Bob (Nov 5, 2008)

I have a Japan only model SBQK079 witch 8f32.
The serial number says it was produced in December 2007.
Worn it is running with ~ +1 s/month
Unworn is running with ~ + 2-3 s/month
I think I'm a little bit lucky :-d
Marcel


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## Catalin (Jan 2, 2009)

Sideshow_Bob said:


> I have a Japan only model SBQK079 witch 8f32.
> The serial number says it was produced in December 2007.
> Worn it is running with ~ +1 s/month
> Unworn is running with ~ + 2-3 s/month
> ...


The more recent JP models have been consistently better ...

Probably you might be able get a consistent +1s/m if you find a warm spot to leave you watch on when not wearing it - I am using 'crown up' on my WiFi router - the position has zero gravitational relevance, but if I leave the watch 'face up' the temperature gets a little higher than when normally wearing it ;-) (more contact surface with the warm source, less surface for the colder surface).


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## warrenn (Jan 15, 2010)

I am curious about the relevance of "made in Japan". Both of my 8F movements were made in Japan despite being in US-marketed watches. Are any of the movements made elsewhere than in Japan?


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## Catalin (Jan 2, 2009)

warrenn said:


> I am curious about the relevance of "made in Japan". Both of my 8F movements were made in Japan despite being in US-marketed watches. Are any of the movements made elsewhere than in Japan?


I believe all 8F movements are made in JP - however it seems that when those are calibrated out of the 'final case' (and then shipped to be cased in US) the results are not as good as when cased in JP (and presumably are calibrated with that specific case in mind).

It might also be that quality control on the final product is much tighter in Japan.


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## warrenn (Jan 15, 2010)

Interesting. I am trying to imagine a production model where this would happen and am coming up empty. As far as I understand, the movements are not capable of being calibrated (except for the two jumpers, which have a very small effect < 64 ms/d). Do they really test for accuracy (as part of quality control) when the movements are put into the cases? (Most instruments which are subject to these tests come with paperwork showing it, in my experience.) Is there any hard evidence for any of this, in particular that the quality control is better in Japan than in the US? (After all, it is the same company.)

I am inclined to believe that the notion that the Japanese watches are better should be taken with a grain of salt and comes under the category of "the plural of anecdote is not data". A brief perusal of the watchuseek fora brings up a number of 8F watches assembled in both Japan and the US where the errors are >20 s/year.

Cheers,

Warren Nagourney


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## pmbirner (Sep 20, 2009)

My wife's watch states on the back "MOV'T JAPAN" which I'm assuming means the Japan sourced 4F32 movement was cased somewhere else in its 0059 case. The watch was new from one of these Ebay sellers that buys out defunct jewelry stores and resells the merchandise. I had some concern at the time that the watch, though new, might have sat around for several years and be needing a new battery. I was pleasantly surprised to see that according to the Seiko serial number the watch was manufactured in January of 2009. If the watch were a 1999 manufacture it would have meant the battery had been replaced. I saw no indication of the case back having been off as stickers were still in place and there were no scratches. The calendar was set up properly as well which lead me to beleive the original battery was in place and the watch is indeed only a year old. 

It is interesting to read about this "pattern cutting process" in order to adjust the watch. I suspect my wife would kill me if she saw me trying this with her new watch. If her watch is out by 40 seconds or 1 second or 2 minutes at the end of the year I don't think she would be bothered. I am a little disappointed, though, since I purchased it for her in order to sort of vicariously enjoy her watch for its technology.


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## Catalin (Jan 2, 2009)

warrenn said:


> Interesting. I am trying to imagine a production model where this would happen and am coming up empty. As far as I understand, the movements are not capable of being calibrated (except for the two jumpers, which have a very small effect < 64 ms/d). Do they really test for accuracy (as part of quality control) when the movements are put into the cases? (Most instruments which are subject to these tests come with paperwork showing it, in my experience.) Is there any hard evidence for any of this, in particular that the quality control is better in Japan than in the US? (After all, it is the same company.)
> 
> I am inclined to believe that the notion that the Japanese watches are better should be taken with a grain of salt and comes under the category of "the plural of anecdote is not data". A brief perusal of the watchuseek fora brings up a number of 8F watches assembled in both Japan and the US where the errors are >20 s/year.


For the first part - usually all quartz calibers have a way to be calibrated - but since around 1980 certain models use IN FACTORY a digital calibration method - which in turn lead to the fact that some models might have SEPARATE adjustment methods in factory (almost never documented) vs. at a normal watchmaker (with the second very often missing for japanese models - to the dismay of watch enthusiasts like many members of this forum).

Anyway - in the case of 8F calibers there is a one-way USER calibration - however that is different than the FACTORY calibration !!! In case you would have bothered to check how the user calibration is made you would have noted that Seiko is VERY specific (actually in ALL their HEQ) about the fact that any rate measurement should be made with the case closed - from that a very simple exercise of minimal industrial knowledge would suggest that most likely when making 100000 copies of let's say SBQJ015 the factory will adjust all the 8F56 calibers in the production line (non-closed) with a certain OFFSET so that when finally placed in the case the end result will be in the acceptable range of that caliber.

The evidence on a difference in quality control is mostly based on rather empirical evidence (and 'hearsay' - as it is ALWAYS the case with watches) - but for instance the fact that I have NEVER seen a report about an SBQJ015 out of the guaranteed range (and actually I believe all reports have been much better than that) while all the reports on the older 8F models cased in US have been rather bad might suggest that the two factories have a different level of quality control, and basically one of those two factories is not testing the final product ... I will let you decide which one ...


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## South Pender (Jul 2, 2008)

Catalin said:


> For the first part - usually all quartz calibers have a way to be calibrated - but since around 1980 certain models use IN FACTORY a digital calibration method - which in turn lead to the fact that some models might have SEPARATE adjustment methods in factory (almost never documented) vs. at a normal watchmaker (with the second very often missing for japanese models - to the dismay of watch enthusiasts like many members of this forum).
> 
> Anyway - in the case of 8F calibers there is a one-way USER calibration - however that is different than the FACTORY calibration !!! In case you would have bothered to check how the user calibration is made you would have noted that Seiko is VERY specific (actually in ALL their HEQ) about the fact that any rate measurement should be made with the case closed - from that a very simple exercise of minimal industrial knowledge would suggest that most likely when making 100000 copies of let's say SBQJ015 the factory will adjust all the 8F56 calibers in the production line (non-closed) with a certain OFFSET so that when finally placed in the case the end result will be in the acceptable range of that caliber.
> 
> The evidence on a difference in quality control is mostly based on rather empirical evidence (and 'hearsay' - as it is ALWAYS the case with watches) - but for instance the fact that I have NEVER seen a report about an SBQJ015 out of the guaranteed range (and actually I believe all reports have been much better than that) while all the reports on the older 8F models cased in US have been rather bad might suggest that the two factories have a different level of quality control, and basically one of those two factories is not testing the final product ... I will let you decide which one ...


This is a little OT, but I really wish Seiko would take a model like SBQJ015 (or any 8F56-movement model) and add the RC component to it. That way, even with occasional spells of non-reception, it would be at most, maybe, one-half second off. If they would also tiddle it up in fit and finish to near-GS levels, I'd be ecstatic!


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## warrenn (Jan 15, 2010)

I don't mean to flog a (nearly) dead horse, but the following thread contains a post about a Japanese-only watch (SBQJ015) which loses 40 seconds per year:
https://www.watchuseek.com/showthread.php?t=50458

I would conclude from this discussion that there are two ways of "calibrating" a watch: cut (or don't cut) the traces on the circuit board, which gives one +32 ms/d to -64 ms/d correction (much less than I need) or select for distribution watches which fall in the advertised spec and throw away the ones which do not. I will probably make one more attempt to get one in spec before considering the Japanese-only option.

My reluctance in buying from an importer is that these watches are 3x as expensive as the one I have. They usually have a Ti case and sapphire window, but these options don't, in my opinion, justify my spending an additional $300.


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## Catalin (Jan 2, 2009)

warrenn said:


> I don't mean to flog a (nearly) dead horse, but the following thread contains a post about a Japanese-only watch (SBQJ015) which loses 40 seconds per year:
> https://www.watchuseek.com/showthread.php?t=50458
> 
> I would conclude from this discussion that there are two ways of "calibrating" a watch: cut (or don't cut) the traces on the circuit board, which gives one +32 ms/d to -64 ms/d correction (much less than I need) or select for distribution watches which fall in the advertised spec and throw away the ones which do not. I will probably make one more attempt to get one in spec before considering the Japanese-only option.
> ...


Interesting link, but I believe the guy most likely has a defective one - see also https://www.watchuseek.com/showthread.php?t=344848 and https://www.watchuseek.com/showthread.php?t=227624 (it seems to always have the worse problems in January and I would also say that the watch got a few shocks - even with a slightly loose cannon pinion you need some shocks to get that kind of results).

On calibration - the user calibration is pretty much as you have read, the factory calibration is totally unknown (and might also be a one-time process) - but the 'get lucky or not' approach is even less known ;-)


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## malc77 (Jun 23, 2009)

I have several Seikos with 8F32 movements. They all gain when worn between 30 and 60 seconds/year and although I have resorted to 'pattern cutting' only a small portion of the error can be 'removed' of course. It's best to take care when pattern cutting as it is quite a delicate operation- and make sure you can reset the perpetual calendar when the battery is replaced, as its settings will be lost.
I have made some measurements of rate v temperature which I will present to the forum later, but very roughly one watch loses 43 sec/yr at 5degC, gains 8sec/yr at 9degC, gains 36sec/yr at 24degC, and loses 43 sec/yr at 31degC. Another watch behaves somewhat similarly, but oddly gains about 43sec/yr at 31 degC. (I use a thermostatically controlled oven and a radio clock for the tests.) There is little doubt that wearing the watch 24/7 will give the most consistent rate - even if it is some way from zero!
An Omega Constellation and Longines VHP both with perpetual calendars and (almost identical) thermo-compensated movements perform far better - they both have a relative rate gain at increasing temperatures- although the Longines has lost less than 1/30 second over four months overall. 
A Citizen Exceed, whilst not having the lowest value for absolute rate (at about + 8 seconds/year), has a rate almost completely independant of temperature changes and so the indicated time is very predictable worn or unworn. It is a great pity that its absolute rate cannot be adjusted.


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## Catalin (Jan 2, 2009)

pmbirner said:


> My wife's watch states on the back "MOV'T JAPAN" which I'm assuming means the Japan sourced 4F32 movement was cased somewhere else in its 0059 case. The watch was new from one of these Ebay sellers that buys out defunct jewelry stores and resells the merchandise. I had some concern at the time that the watch, though new, might have sat around for several years and be needing a new battery. I was pleasantly surprised to see that according to the Seiko serial number the watch was manufactured in January of 2009. If the watch were a 1999 manufacture it would have meant the battery had been replaced. I saw no indication of the case back having been off as stickers were still in place and there were no scratches. The calendar was set up properly as well which lead me to beleive the original battery was in place and the watch is indeed only a year old.
> 
> It is interesting to read about this "pattern cutting process" in order to adjust the watch. I suspect my wife would kill me if she saw me trying this with her new watch. If her watch is out by 40 seconds or 1 second or 2 minutes at the end of the year I don't think she would be bothered. I am a little disappointed, though, since I purchased it for her in order to sort of vicariously enjoy her watch for its technology.


I believe 4F is using CR1612 good for about 5 years while 8F is using CR2412 good for 8-10 years.


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## U5512 (Feb 25, 2006)

I've this Seiko 8F56 for well over a month, and I was wearing it may be 5 times and the rest it just sat on the counter where the temperatures ranges from 60F-70F. It was gaining 3 seconds during all of that time so I am thinking when I wear it regularly it will be in the range of +- 20 seconds per Seiko's specs.


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## warrenn (Jan 15, 2010)

Thanks for the input - this is an SLT109, which is the one of the two 8F watches still available in the US. My wife got me one for Christmas and I returned it since the large "milemarker" wheel dug into my wrist and it was fairly uncomfortable (it was also very heavy). I purchased instead the SLT079 (the other 8F watch) which is a bit lighter (but still heavy) and was more comfortable. I returned it to the dealer today for shipping to Seiko US to repair the 0.14 s/day drift. Both watches can be purchased for about $170.

Both watches are available in only a few places and one gets the sense that Seiko is discontinuing the 196 kHz movements in US watches. As the graph posted by dwjquest illustrates, the 8F movements have a somewhat smaller temp sensitivity than 32 kHz watches (due to the way the 196 kHz crystal is cut). Too bad that this avenue to inexpensive high accuracy is being cut off.


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## Haqnut (Nov 13, 2006)

Interesting ;


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## junlon (Dec 30, 2007)

Just curious if anyone has actually cut the pattern to improve the accuracy. If yes, how difficult to cut the pattern? How much improvement did you get? Did you get just -0.064 sec/day (+0.032 sec/day) or "*more*"?



Hans Moleman said:


> From the PDF at:http://www.pmwf.com/Watches/Seiko/4F32A,8F32A,33A,35A.pdf
> 
> It looks like the wire runs over a small indentation, so that you can grab it. Or push down with a needle I guess.


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## webvan (Dec 11, 2008)

Good question, might give it a try on my 8F56 based Pulsar since it seems to be running at +28 at room temp and +16 when worn, so cutting P2 would give me -23spy. I'm a bit concerned by Malc77's post above though :


> It's best to take care when pattern cutting as it is quite a delicate operation- and make sure you can reset the perpetual calendar when the battery is replaced, as its settings will be lost.


Apparently you have 3 minutes before the perpetual calendar loses the plot so that might be enough to do the cutting and put the battery back.


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## Catalin (Jan 2, 2009)

webvan said:


> Good question, might give it a try on my 8F56 based Pulsar since it seems to be running at +28 at room temp and +16 when worn, so cutting P2 would give me -23spy. I'm a bit concerned by Malc77's post above though :
> Apparently you have 3 minutes before the perpetual calendar loses the plot so that might be enough to do the cutting and put the battery back.


The pattern cutting is (a lot) more delicate than setting the calendar, which does not require any watchmaker skills (other than patience) - for some reason my instinct would suggest in doing a full-full reset after cutting the pattern ...


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## webvan (Dec 11, 2008)

Ah ok, have you done the "pattern cutting" yourself and found it more difficult than expected ?

How do you do a "full-full reset", just leave the battery out for 3+ minutes?


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## Catalin (Jan 2, 2009)

webvan said:


> Ah ok, have you done the "pattern cutting" yourself and found it more difficult than expected ?
> 
> How do you do a "full-full reset", just leave the battery out for 3+ minutes?


The problem with 'pattern cutting' is simply that the actual thing you need to cut is rather difficult to see with the naked eye and I assume you need very steady hands to cut it precisely - but I have not done it myself (if I will - most likely I will work with a stereoscopic microscope that some of my friends in electronics have at their lab).

And yes, leaving the battery out for 5-10 minutes should do the trick.


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## junlon (Dec 30, 2007)

I suspect "pattern cutting" may not give us +0.064 sec/day (or -0.032 sec/day) adjustment as stated in the manual. 
Many people reported their 8F movements were way out of Seiko's spec. If we can not 100% believe Seiko's spec in 8F, how much can we believe "pattern cutting" improvement in accuracy? :-(


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## Catalin (Jan 2, 2009)

junlon said:


> I suspect "pattern cutting" may not give us +0.064 sec/day (or -0.032 sec/day) adjustment as stated in the manual.
> Many people reported their 8F movements were way out of Seiko's spec. If we can not 100% believe Seiko's spec in 8F, how much can we believe "pattern cutting" improvement in accuracy? :-(


I tend to believe Seiko's general point on how the adjustment is made - maybe there have been some models that over time have drifted dramatically out of original specification, but there is no point in believing that the digital adjustment does not work as a rule - it might not work in certain conditions when the 'cut' was not done very careful (remember, it is a trace that you can not see well with the 'naked eye', let alone easily 'manipulate' with your hands), or maybe some OTHER trace was already cut !!! (there are many combinations that are not allowed).


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## ChronoStop (May 18, 2009)

junlon said:


> Just curious if anyone has actually cut the pattern to improve the accuracy. If yes, how difficult to cut the pattern? How much improvement did you get? Did you get just -0.064 sec/day (+0.032 sec/day) or "*more*"?


Yes I just performed the surgery on my 8f32 that was running about +0.4 s/d. After i cut the P2 trace and reset the watch and calender the watch now runs +0.12 s/d fast. Got more improvement than the manual stated. I don't thing you could perform the correction and get the the battery back in in less than 3 minutes. You need to remove the metal shield with four screws, then lift the circuit body out to do the mod. The P2 trace runs across a hole in the board. Any small pointed metal probe would work. Finding the hole needs a loop but broke the wire on a hard cardboard background. I reassembled the board, shield and battery. Did a full reset of the calendar.


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## junlon (Dec 30, 2007)

ChronoStop said:


> Yes I just performed the surgery on my 8f32 that was running about +0.4 s/d. After i cut the P2 trace and reset the watch and calender the watch now runs +0.12 s/d fast. Got more improvement than the manual stated. I don't thing you could perform the correction and get the the battery back in in less than 3 minutes. You need to remove the metal shield with four screws, then lift the circuit body out to do the mod. The P2 trace runs across a hole in the board. Any small pointed metal probe would work. Finding the hole needs a loop but broke the wire on a hard cardboard background. I reassembled the board, shield and battery. Did a full reset of the calendar.


Thanks for the good info. One of my 8F runs about +0.3 sec/day. I have been debating with myself if it is worth the effort to cut the pattern. If I can get the same -0.28 sec/day by cutting the P2 pattern, my 8F will be almost perfect.

Can you explain a bit how you "lifted the circuit body out"?


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## webvan (Dec 11, 2008)

@ChronoStop - since you wrote you'd just performed the adjustment, have you checked it over some time. It's worrying that you got a -0.28spd (102spy ?!) adjustment versus the expected -0.064, that's x4.375 more ! How are you checking the rate? Catalin's video method over a week seems the fastest reliable way to do it based on my experience.


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## malc77 (Jun 23, 2009)

I have pattern cut three 8F32 movements and did get about the change in rate that Seiko state. All of my movements were gaining between 40 and 60 seconds per year and so although I could improve their rates, I could not get near zero . 
It took way over three minutes to complete the cutting- mainly because of having to reach the track first- so expect to have to reset the calendar. 
As others have said, the watch temperature is important when comparing rates- if kept in a very cold room, all of mine, as expected, lose relatively- and if I didn't wear them their rates would be near zero.



junlon said:


> I suspect "pattern cutting" may not give us +0.064 sec/day (or -0.032 sec/day) adjustment as stated in the manual.
> Many people reported their 8F movements were way out of Seiko's spec. If we can not 100% believe Seiko's spec in 8F, how much can we believe "pattern cutting" improvement in accuracy? :-(


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## ChronoStop (May 18, 2009)

webvan said:


> @ChronoStop - since you wrote you'd just performed the adjustment, have you checked it over some time. It's worrying that you got a -0.28spd (102spy ?!) adjustment versus the expected -0.064, that's x4.375 more ! How are you checking the rate? Catalin's video method over a week seems the fastest reliable way to do it based on my experience.


I have performed this mod on four watches and this one is the only one that changed that much. The rest were closer to the expected.
I use a Citizen CQT-101 that seems very consistent.


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## webvan (Dec 11, 2008)

My latest 9F56 SLT047P with a serial from 2000 is at 30spy when warn and +77spy at room temperature. Quite poor. On the other hand almost eveyone seems very happy with their E510 (except when they suddently "lose it".). The -23spy pattern cutting isn't going to help much.

Anyone know if the circuit can be swapped between 8F56 movements ? I accidentally killed my Pulsar the other day (don't ask...well if you need to know, I touched the coil when removing the battery) and it was running at +14 (warm)/+37(room) before pattern cutting.


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## ronalddheld (May 5, 2005)

How unfortunate that you lost the +14 sec on the Pulsar.


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## webvan (Dec 11, 2008)

More than the +14 it's unfortunate that I "lost" the watch ;-)

Any thoughts on swapping the circuit, have you ever tried that? Can't remember if you're the one with the amazing 8F56 collection ;-)


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## Catalin (Jan 2, 2009)

webvan said:


> My latest 9F56 SLT047P with a serial from 2000 is at 30spy when warn and +77spy at room temperature. Quite poor. On the other hand almost eveyone seems very happy with their E510 (except when they suddently "lose it".). The -23spy pattern cutting isn't going to help much.
> 
> Anyone know if the circuit can be swapped between 8F56 movements ? I accidentally killed my Pulsar the other day (don't ask...well if you need to know, I touched the coil when removing the battery) and it was running at +14 (warm)/+37(room) before pattern cutting.


The coil can be certainly swapped by a good watchmaker ... actually one might even find a replacement coil so you can again have both working ...


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## webvan (Dec 11, 2008)

Yes that's a thought, was more curious as to the actual printed circuit being swappable so I can get the better accuracy of the Pulsar. Will give it a try as soon as I find a replacement screwdriver to remove the four tiny screws of the protection plate.


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## webvan (Dec 11, 2008)

Got a new 8F56 from 1999, the 8F56-0020 and after 24 hours of testing it seems to be at about +75spy at room temperature, which should translate to +40 at router temperature, barely meeting the +/-20 spy of Seiko in absolute value. Pretty much like my 2000 SLT047P.

Is there a topic with a list of 8F56 watches and their accuracy ? If not maybe we could start one to see if there is a pattern with watches going faster as they age.


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## Catalin (Jan 2, 2009)

webvan said:


> Got a new 8F56 from 1999, the 8F56-0020 and after 24 hours of testing it seems to be at about +75spy at room temperature, which should translate to +40 at router temperature, barely meeting the +/-20 spy of Seiko in absolute value. Pretty much like my 2000 SLT047P.
> 
> Is there a topic with a list of 8F56 watches and their accuracy ? If not maybe we could start one to see if there is a pattern with watches going faster as they age.
> ...


My own 8F33 from US/2000 is +75/+65 (and -15 into the fridge), so the range seems common in watches from US and from around 2000 ... it would be very interesting to find 2-3 JP-made 8F models from the same period but it might not be a huge difference ...


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## webvan (Dec 11, 2008)

That's what I'm thinking too, when I have warm numbers for the 8F56-0020 tomorrow I'll post that data for the three 8Fxx I've used.


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## webvan (Dec 11, 2008)

webvan said:


> Yes that's a thought, was more curious as to the actual printed circuit being swappable so I can get the better accuracy of the Pulsar. Will give it a try as soon as I find a replacement screwdriver to remove the four tiny screws of the protection plate.


Been meaning to update this for ever, but YES the circuit is indeed swappable as I found using the one from my dead Pulsar 8F56 (14/-10 after P2 tweak) into my SLT047.

Wasn't sure where to post this but a current eBay auction attributes the design of the SLL015 :










to one Jorg Hysek and it looks like my 8F56-0020 above.


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## webvan (Dec 11, 2008)

As luck would have it I came across a used SLL015 today, pretty beat but cheap and the fiber pen took car of most of the scratches on the bracelet thanks to the softness of Titanium. Unfortunately the crystal is scratched and that's a tad annoying. Anyone know where a replacement crystal could be sourced? Quite a bit of searching hasn't turned anything up yet.

I really like that Titanium color and its lightness...will now be timing that bad boy ;-)


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## webvan (Dec 11, 2008)

Hans Moleman said:


> From the PDF at:http://www.pmwf.com/Watches/Seiko/4F32A%2C8F32A%2C33A%2C35A.pdf
> 
> It looks like the wire runs over a small indentation, so that you can grab it. Or push down with a needle I guess.


The picture in the manual is a bit confusing if you're trying to cut P1 or P2 without removing the circuit as it is shown from the the reverse side. I mirrored it with a picture editor to show what it looks like once you've removed the battery.


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