Advice please. Accuracy after $1300 service. Valjoux 7751

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Sarbie
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Sun Oct 15, 2017 7:27 am

Hi guys. I don't want to name or shame anyone as I have never had a complete service done on a watch and whilst I think my expectations are justified, I really would like more experienced opinions before I send my watch back in.

Complete overhaul done a couple of months ago before I joined TKNZ. Little shout out here to say I am enjoying the forum immensely. :thumbup:

Watch running at around -30 seconds a day....probably closer to -35.

Should I be expecting greater Accuracy?

Thanks for your opinions and advice in advance.
the gold bracelet thing was my dads necklace he gave me before he died...but i dont like things round ma neck
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anzac1957
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Sun Oct 15, 2017 8:45 am

Do you know what it's rated accuracy is for the watch?
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Sarbie
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Sun Oct 15, 2017 8:57 am

Hi Anzac. Thanks for the reply.

In my reading my understanding is +/-15 seconds but that is not from an official source.

Apparently they are very accurate movements and most owners are getting less than +10 seconds a day. Running slow also seems rare.
the gold bracelet thing was my dads necklace he gave me before he died...but i dont like things round ma neck
Horos
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Sun Oct 15, 2017 9:00 am

If you drop it back to the service people they can put it on their timer and reset to an equivalent gain. It is usual to set to a 5=15 second gain after a service. For that kind of money it certainly should be better than it is.
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Sarbie
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Sun Oct 15, 2017 9:01 am

Service was carried out by the official NZ agents/service center for the brand.
the gold bracelet thing was my dads necklace he gave me before he died...but i dont like things round ma neck
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Sarbie
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Sun Oct 15, 2017 9:02 am

Thanks Horos. That is what I thought too. I am wondering if the completely dis-assembled movement may need some time to settle. However I was not advised of this.
the gold bracelet thing was my dads necklace he gave me before he died...but i dont like things round ma neck
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Don
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Sun Oct 15, 2017 10:42 am

Sarbie wrote:
Sun Oct 15, 2017 7:27 am
...I really would like more experienced opinions before I send my watch back in.

Complete overhaul done a couple of months ago before I joined TKNZ. Little shout out here to say I am enjoying the forum immensely. :thumbup:

Watch running at around -30 seconds a day....probably closer to -35.

Should I be expecting greater Accuracy?

First of all, I'm glad that you've been enjoying TKNZ :) We're fortunate here to have members like Horos, whose experience we've benefited from greatly.

Before sending your watch back, you may like to find out more about its state, not only so that you can be sure of the apparent fault, but so that once the watchmaker has rectified the movement, you have some objective ways of assessing the change.

Sarbie wrote:
Sun Oct 15, 2017 7:27 am
...In my reading my understanding is +/-15 seconds but that is not from an official source.

Apparently they are very accurate movements and most owners are getting less than +10 seconds a day. Running slow also seems rare.

An ETA/Valjoux 7750 comes in three "Executions" or "Grade"--Elabore, Top, and Chronometer. Elabore grade is adjusted in three positions with an average rate of +/-5 sec/day with a maximum daily variation of +/-15 sec/day. Top grade is adjusted in five positions with an average rate of +/-4 sec/day with a maximum daily variation of +/-10 seconds/day. Finally, the Chronometer grade meets COSC with average rate of -4/+6 sec/day with a maximum daily variation of +/-5 sec/day.

Find out which specification applies to your watch. Most Chronometer-certified modules will likely advertise the fact with "Chronometer" on the dial, so if it does not, assume it to be Elabore, unless your watch happen to be an IWC-rebuilt 7750, in which case a different standard applies. Next you'll want to have an object method to ascertaining accuracy, and for this, read this topic from earlier this year... viewtopic.php?f=7&t=5673#p58573

For a brand new or recently-serviced watch, precision is more important than accuracy. That is, you're looking for the results in all position to be tightly grouped, rather than just averaging to be "accurate". If the figures are tightly-grouped, then it would be a simple regulation to get it sitting where it should, and this includes the ability to take in your personal error. If there are vast positional errors after a full overhaul, then it has obviously been poorly carried out.
Don
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Sarbie
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Sun Oct 15, 2017 12:35 pm

Don.
Thanks a bunch. Incredibly helpful. Hard to digest all the info right now (at the pools with the kids) but will take it in better when I get home.

I have been keeping an eye on it for a couple of weeks and always seems to be -30 seconds out but havent placed crown up, crown down etc.

Again a big thanks for taking the time to share your knowledge.
the gold bracelet thing was my dads necklace he gave me before he died...but i dont like things round ma neck
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Sarbie
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Mon Oct 16, 2017 8:14 am

Starting the tests this morning Don as per the post you linked to.

Gotta say I'm pretty curious.
the gold bracelet thing was my dads necklace he gave me before he died...but i dont like things round ma neck
Coach
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Mon Oct 16, 2017 8:13 pm

My Seiko gets poor -25seconds when its not fully wound but -8 when I wear it for a few days.

I used WatchCheck (until my phone got stolen) to check accuracy
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Sarbie
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Mon Oct 16, 2017 9:54 pm

Sorry to hear about your phone coach.
Thanks for the heads up about watch check.

I've got it on test in varying positions 12hrs at per position. It's going to take a few days.

Good tip on running slow when the reserve gets low, cheers.
the gold bracelet thing was my dads necklace he gave me before he died...but i dont like things round ma neck
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Sarbie
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Thu Oct 19, 2017 9:46 am

Sarbie wrote:Sorry to hear about your phone coach.
Thanks for the heads up about watch check.

I've got it on test in varying positions 12hrs at per position. It's going to take a few days.

Good tip on running slow when the reserve gets low, cheers.
Nearly finished doing my 12 hr tests. Results in tomorrow.

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the gold bracelet thing was my dads necklace he gave me before he died...but i dont like things round ma neck
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Don
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Fri Oct 20, 2017 3:33 pm

Coach wrote:
Mon Oct 16, 2017 8:13 pm
My Seiko gets poor -25seconds when its not fully wound but -8 when I wear it for a few days.
...

This is due to isochronous error, whereby the daily rate—or rather instantaneous rate—can differ according to how much power is in the main spring. I’m assuming this might be your Seiko 5 SNZH60 (Cal 7S36, no auxiliary manual-winding), and such vast difference in the figures could mean that the “-25 sec”/day is not only not fully-wound, but insufficiently wound. There is no reason why you would be able to enjoy the -8 sec/day from start-up if you wind the main spring sufficiently. Mechanical movements are designed to be most accurate, with reasonably stable daily rate, between the states of fully-wound and half-wound, so winding the main spring to at least half-wound will ensure optimal rate.

The problem might be with Seiko’s instruction for their Cal 7S26/7S36 regarding how to start up the movement.


Image


IMO, as effective as Seiko’s Magic Lever is, following the above guideline does not wind the mainspring quite enough to take it to anywhere near half-wound. You can try it for yourself if you own a watch with a power-reserve indicator, try to swing it for 30 sec, and see how much the “power” goes up. Seiko, of course, makes assumption about how active most of us are during our work days. For many of us who are desk-bound most of the time, our movements are less than “normal”. It’s not surprising most owners do not wind their 7S26/7S36 enough before setting the time, and I’m guessing this is actually what accounts for many on watch forums stating their newer Cal 4R36-equipped Seiko are more accurate than the older 7S26—despite similar on-paper specs.

They just don’t wind their 7S watches enough before wearing.

Currently, I only one 7S26 watch in my rotation, the Monster SKX779, and actually, the only non-handwindable watch in the rotation. When it is this watch’s turn, I make sure it is wound properly before setting the time. What I like to do is swirl it horizontally in a small circle the circumference of a tennis ball, the same motion was swirling brandy in a glass, or you can do the swing illustrated in the manual above. I do this around 400 times, then set the time.
Don
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Sarbie
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Sun Oct 22, 2017 12:26 pm

OK results are in.

Each measurement was 12 hours so needs to be doubled for a full day result.

Face up test was done 3 times because the first measurement was out of whack compared to the rest, my feeling is that the watch was not wound first and possibly made a difference.


12 Hour test

Crown up.............-6 seconds
Crown down.........-5 seconds
Face up...............-12 seconds (possibly less wound)
Face up...............-6 seconds
Face up...............-7 seconds
Face down............+5 seconds
Face down............+6 seconds (re tested due to the + anomaly)
Wearing................-5 seconds
12 up...................-6 seconds
12 down................-6 seconds

if all results are doubled the arrived accuracy is -14/+12 seconds per day if -12 second anomaly is removed.

any one like to share their opinions?
thanks
the gold bracelet thing was my dads necklace he gave me before he died...but i dont like things round ma neck
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Stevo_iwc
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Sun Oct 22, 2017 3:31 pm

I’d be OK with those results but then accuracy is something that interests me but seldom concerns (me unless it is significant enough to indicate a fault). As Don mentioned grade movement is important and if the movement is a standard valjoux then those results are ok. Having said that it could be regulated further if it concerns you.


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