Thanks Stan, this was very nice of you to write up and with great pictures. :-!

mike

 

Any confirmation for the clockwise/counterclockwise accelerating/slowing down? I have a dw-5300 which gained 2s a day, now I turned it much clockwise and the end result is that it loses about 2s a day :f, it may be that I broke the thing by applying too much pressure. I'm running a test now, it's near the original position but a bit clockwise. We'll see what happens. Is there any data on temperature change and its effect on the quarz crystal?

 

Now, I turned the potentiometer counterclockwise almost to the original position with good results: from what I can tell ( one day test period) the watch is losing 1/10s a day, so that makes 3 seconds a month. Seems very good but I need to test it longer. Very nice .

 

my Riseman was about 4.67 seconds/month too fast. While
this was still within Casio's +/- 15s spec, it was much
worse than the 0.5s/month of my G-7700. I read the howto
article about adjusting G-Shocks and decided to try it on my
Riseman, especially since I could put to use some of the
measuring equipment that accumulated beside my desk over the
years.

Those tools are an oscilloscope and - more importantly - a
counter:

I found the clock signal on the third contact pad in the
group above the alti button.

The signal has some intermediate state while rising, so I
set the counter to trigger on the downward slope instead:

This looks like a 32.768 kHz quartz divided by 48. Adjusting
it to a display of 682.666667 Hz would be a bad idea
however, since the counter itself is probably out of
calibration and the load of the probe might also be detuning
the G-Shock's oscillator. Instead, I went for the relative
adjustment of -1.87 ppm = 4.67s/month:

...so the actual adjustment made was 1.15 mHz = 1.69 ppm,
leaving the Riseman 0.18 ppm fast, which computes to 0.45
s/month. Now time has to tell if I got the maths right

 

my Riseman was about 4.67 seconds/month too fast. While
this was still within Casio's +/- 15s spec, it was much
worse than the 0.5s/month of my G-7700. I read the howto
article about adjusting G-Shocks and decided to try it on my
Riseman, especially since I could put to use some of the
measuring equipment that accumulated beside my desk over the
years.

Those tools are an oscilloscope and - more importantly - a
counter:

I found the clock signal on the third contact pad in the
group above the alti button.

The signal has some intermediate state while rising, so I
set the counter to trigger on the downward slope instead:

This looks like a 32.768 kHz quartz divided by 48. Adjusting
it to a display of 682.666667 Hz would be a bad idea
however, since the counter itself is probably out of
calibration and the load of the probe might also be detuning
the G-Shock's oscillator. Instead, I went for the relative
adjustment of -1.87 ppm = 4.67s/month:

...so the actual adjustment made was 1.15 mHz = 1.69 ppm,
leaving the Riseman 0.18 ppm fast, which computes to 0.45
s/month. Now time has to tell if I got the maths right

Did you actrually turn the trimmer adjustment screw? You didn't mention about the trimmer like Stan did.

 

Please update and let us know if you got it correct. When you check it again in a while, also let us know how far off it is.

 

it might have been easier to pick an atomic riseman instead, but nevertheless a nice equipment and a nice tutorial ;-)


regards, holger

 

it might have been easier to pick an atomic riseman instead, but nevertheless a nice equipment and a nice tutorial ;-)

I have to admit that this is an atomic one. Let me explain . I'm making extensive use of the stopwatch and I chose the riseman because the daytime is always visible in stopwatch mode, so I wouldn't have to switch between timekeeping and stopwatch mode twenty times a day as I had to with my G-7700.

The result is that my riseman spends most of its nights in stopwatch mode, which prevents it from syncing automatically. So before the adjustment my riseman was actually less accurate than my g-7700 unless I happened to have it manually synced a couple of days before.

Please update and let us know if you got it correct. When you check it again in a while, also let us know how far off it is.

Will do.

 

Great work!:-!

But where is the Trimpot screw located in the Riseman?

Can't see it in the picture!:think:

 

But where is the Trimpot screw located in the Riseman?
Can't see it in the picture!:think:

I've attached a crop of the second image with labels added.

regards,
andreas

 

Wicked. Just plain wicked. Do all Gs have these contact pads?

If so...maybe you should start a side business adjusting Gs :-!.

 

Wicked. Just plain wicked. Do all Gs have these contact pads?

If so...maybe you should start a side business adjusting Gs :-!.

Heh heh :-d I was thinking the same thing. I would LOVe to have that accuracy on my 5600C.

 

Good work, Stan. Adjusting the watch's accuracy has been a task that I had to do with all my G-Shock watches. With some amount of research some 7 years ago, I learned how to do it. Now all my Gs won't deviate by a minute a year!

 

Three minutes/month is good enough if it is the amount of gain. Not loss. That is to compensate for low battery condition...and your watch is not even out by a minute a year!

 

It depends on the watch model. My Mudman G-9000 has its trimmer screw turned clockwise to slow it down, and turned the other way to make it faster. My GL-150, G-2500, G-7300 are just the reverse.

 

Everybody wants an accurate timepiece, man. You can do it yourself!

 

Hi, dys! Obviously, you know how to apply oscilloscope and a counter for the purpose of adjusting the acuracy of a G-Shock watch and probably any other quartz watch and I believe that the adjustment (the way you did it) took only once for a watch. So how's the watch's accuracy now?

 

Hi, dys! Obviously, you know how to apply oscilloscope and a counter for the purpose of adjusting the acuracy of a G-Shock watch and probably any other quartz watch and I believe that the adjustment (the way you did it) took only once for a watch.

Right --- this is the main difference to Stan's approach. You can observe the effect of turning the trimmer almost instantly using the frequency counter and don't have to wait days to observe it.

So how's the watch's accuracy now?

It didn't sync for 468 hours and is 0.84 s ahead of legal time at the moment. Considering the leap second at the end of december, the watch is actually running 0.16s/month slow. While this is not the expected result of being 0.45s/month fast, it is more accurate than predicted.

regards,
andreas

 

I see that it's OK for you to have your watch's accuracy on the minus (-) side? I prefer to go for the plus (+) side to compensate for low battery condition. Can you show me how your calculations (maths) were? Thanks in advance, dys!

 

I see that it's OK for you to have your watch's accuracy on the minus (-) side?

Sure, if I wanted to make sure it is ahead of time during the next year, I'll just set it two seconds fast.

I prefer to go for the plus (+) side to compensate for low battery condition.

Good point for non-solar watches. For solar ones, I would rather suspect the average voltage to rise now that the days are getting longer again.

Can you show me how your calculations (maths) were? Thanks in advance, dys!

Which part do you mean exactly? I'm sure I'd point out all the obvious things and miss the key point if I just started to elaborate aimlessly

 

With your test equipments- oscilloscope and a frequency counter, you get figures and numbers. Then you use calculations from those readings. You turned the trimmer adjustment screw, of course, and somehow expected to see a reading. By how much should the reading go up or down to get an expected result is what I'm trying to figure out here. You understand how to use your equipments and probably know when somebody's watch is running slow or fast by using those equipments.

What I did to my watches was similar to stan's approach: trial-and-error. Yours is straightforward scientific approach. I don't expect you to share that knowledge with everyone, dys. But it seems that I'm the only one very interested. Yo may send me a private message if you want.

 

Sorry for the late followup...

With your test equipments- oscilloscope and a frequency counter, you get figures and numbers. Then you use calculations from those readings. You turned the trimmer adjustment screw, of course, and somehow expected to see a reading. By how much should the reading go up or down to get an expected result is what I'm trying to figure out here.

I see. If the frequency counter would have a very good timebase and would be calibrated, you could simply turn the trimmer until the display reads 682.666667 Hz. Sadly, the counter I bought surplus cheaply doesn't have the "high precision timebase" option, and hasn't been calibrated for years. It is probably off by 5 seconds a month as well. That is why this route wouldn't lead to a calibrated Riseman.

However, from comparing the Riseman to a DCF-77 clock, I knew it was off 4.6 s/month. This is a relative false-ticking of 0.000187%. What I did was adjusting the trimmer until the counter display did decrease by this relative amount.

The scope was just there to hunt down the signal and to spot the right trigger settings. I didn't want to search the pads with the counter alone, since one of them might be hooked up to the charge pump for the LCD or the inductor for the backlight, etc, which could break the counter's input amplifier. The scope's input is much more robust (400V vs. 5V).

regards,
andreas

 

For try to adjust G-7700 series,
i have g-7710, trimmer screw turned clockwise to slow it.

No adjust 80 sec/month fast
Adjust result Now 6 sec/month fast

 

For try to adjust G-7700 series,
i have g-7710, trimmer screw turned clockwise to slow it.

No adjust 80 sec/month fast
Adjust result Now 6 sec/month fast

THANKS FOR ALL OF YOU !
I just try to adjust some of my g-shocks .
My MRG-110 is same as above BUT DW-8300 ISN'T .

 

ok............

I too want to adjustment watch, my 6900, for better accuracy, however, does a fresh battery vs. an older yet good working battery with still a very good glow when the light is pushed, anyway...

is there a difference? in the accuracy of watch just based on the BATTERY???

please respond,
southpaw

thanks in advance...

 

Is there a adjustment screw on Pathfinders as well?
I have a PAW1500 and PAW2000 which I would like to adjust accurately for times when atomic sync is out of range.

 

do all the new G's also have a trimmer?

 

Hi, regarding the method using a stopwatch to adjust, if the watch with the stopwatch function is unadjusted/inaccurate itself, would it also affect the accuracy of the stopwatch?

I am unsure how the stopwatch mode works but I assume it is in somehow linked to timekeeping mode which will of course lead back to the crystal. Using an inaccurate tool to adjust an inaccurate watch will surely lead to a bigger headache. Please correct me if I'm wrong.

In that case, I believe for people who does not have an atomic clock or are in countries that cannot receive signals, we can only use the internet time to adjust the precision of our watches. Here again, another problem arise - it will only be as good as the amount of lag of the computer/browser and internet connection.

Any opinions?

 

You only use the stop watch for a very short amount of time to establish the difference to the base time. Over this short amount of time the stop watch will not be inaccurate. In principle, though, you are right that the stop watch also depends on the main quartz assembly and that the adjustment tool should be accurate. It's just because you are using such a brief interval that it doesn't matter.

For the base time and the internet lag it's similar. You only need to establish a reference and measure the difference to the reference. As long as the reference stays constant and the method used to measure the difference is also constant, it doesn't really matter if the reference is off. What you want to get at is the time differential not the absolute time. However, I'm thinking that the internet lag can indeed be different from time to time depending on your connection speed, the server load and how your computer feels that day.

So using an atomic G-shock that has been synced very recently (ideally right after syncing) should be an even better base time than using the internet.

Till

 

Re: you got me started: a couple more examples (long post)

Hi,

This thread got me started. I always thought accuracy couldn't be improved on affordable quartz watches.

Still I wonder why companies like Casio don't include a simple digital feature to subtract or add a certain number of hundreths of a second every nigt at midnight. Something like the adjustment you can do on their thermometre watches (+ or - 0.1 degrees C).

Anyhow. I tried a couple of watches to see if there is a trimmer screw.

First to go was my old trustworthy W-780. A classic watch from the end of the eighties I keep in a drawer. This one has a trimmer screw. I'm now playing with it. So I can't comment on the results yet. Sorry about the amateurish pics.;-)

For those who don't remember or know the W-780: it's a classic 100m slim stainless casio that stems from my boyhood. It was my first casio, now 17-18 years old. This was not a cheap casio. I recall it cost something like 80-90 euros at that time!

Inside this classic you can see the trimmer screw and the large capacity battery.

BTW: can anyone point me to somewhere I could get a new seal for it?

My next experiment was with a recent model, todays counterpart of the classic W-780. It's the W-800H-1AVES. As expected no luck there, unless I missed it.

The back:

Inside:

As some people said: most G-shocks can be adjusted for accuracy. That alone made me curious enough to take the plunge. As I'm not really fond of big watches (small wrists) I tried out the Casio G-7800. I love it. And even on my smallish wrists (just 17,5 cm or 6 inch 7/8) it doesn't look bad at all! :-d.

Compared to something I would normally wear for work or off duty:

But, let's get on with business... Screws undone already.

The shock protection rubber:

Aaaand on to the inside... YES. There is something that looks like a trimmer screw. Can anyone confirm that this is the screw I'm looking for?

I took a shot through a loupe to make it more visible, there's a brownish ring around it inside, hard to see on the pic.

It's a Philips style screw. Anyone had a philips trimmer screw in their G-shocks before? Anyway I tried to gently turn it a couple of degrees as the watch was a few seconds a month slow out of the box (I'd say about -8 seconds a month).

So time will tell if this is the srew for adjusting the accuracy on the G-7800.

I hope I dind't bore you guys with this lengthy post. As I couldn't find any pics of the inside of a G-7800, I decided to post some. It's a great looking and wearing watch. If I can succeed in adjusting it, it willl be among my personal favourites!:-d

Bye

Luca

 

Re: you got me started: a couple more examples (long post)

Hi,

This thread got me started. I always thought accuracy couldn't be improved on affordable quartz watches.

Still I wonder why companies like Casio don't include a simple digital feature to subtract or add a certain number of hundreths of a second every nigt at midnight. Something like the adjustment you can do on their thermometre watches (+ or - 0.1 degrees C).

Anyhow. I tried a couple of watches to see if there is a trimmer screw.

First to go was my old trustworthy W-780. A classic watch from the end of the eighties I keep in a drawer. This one has a trimmer screw. I'm now playing with it. So I can't comment on the results yet. Sorry about the amateurish pics.;-)

For those who don't remember or know the W-780: it's a classic 100m slim stainless casio that stems from my boyhood. It was my first casio, now 17-18 years old. This was not a cheap casio. I recall it cost something like 80-90 euros at that time!

Dang, this is almost the one (pretty sure it's the same module) I got for my 15th (or was it 13th birthday) and that now resides at the bottom of the sea after it got jolted from my wrist when my dinghy capsized big time in a storm...with this reference will try to hunt one down on fleabay, all the better that it can be trimmed!

 

Re: you got me started: a couple more examples (long post)

I was able to adjust the accuracy on my G-2310. I didn't bother with the stop watch. Instead, I used a countdown timer. You see the problem is that when talking about fractions of a second, there is always going to be a variance on when you actually press START and STOP. At least with the CDT, it's only one variance to influence. I got very lucky, in that I made a very small adjustment with the screw for my first test. And that adjustment seemed to be all I needed. The watch was gaining over 1 second per day. Now, it's gaining 1 second every 3 days. I'm going to let it "settle"... expose it to varying temperatures, wearing, and resting for a week's time and see how it does. If need be, I'll try half of the last adjustment to try bringing it closer to just 5 seconds per month.

I have another Casio (vintage solar, non-G) that has a flat head screw (not Philips), and the slot is so thin and shallow that my smallest screwdrivers can't quite get it to turn. Maybe a pen knife blade will do the trick...

 

Re: you got me started: a couple more examples (long post)

To add to this.....the GW5000 is counterclock to speed up, clockwise to slow down. The GWF-1000 series is just the opposite, counterclock to slow, clockwise to speed up. Both of mine are +-2 seconds a month (and that's with human error!).

Anyone wanting to get there's dialed in can PM me.

 

Re: you got me started: a couple more examples (long post)

ADDENDUM:

The scientific approach is really fascinating, but a bit over the top for anyone who doesn't have an oscilloscope. I didn't even bother with a stop watch, as Stan recommended. I just "eyeballed" the time deviation and then turned the trimmer screw a little more or less, depending on how much deviation occurred. In just a couple of days (maybe 5-10 minutes once or twice per day), I ended up with two watches showing a +2 sec/mo deviation (the other two are gaining a little more).

A couple of things I'd like to add to the instructions:

• First and foremost, note the original orientation of the trimmer screw. In most cases it will be a Philips head screw (+), while older ones will have a flat head screw (-). You can look at the screw slot position relative to any markings on the module, or create your own mark with a fine pen. It's easier to note the position with a flat head, because there are only 2 ends to the slot and generally you won't be turning the screw more than 45 degrees.
• The trimmer screw should turn without much effort, however on an older module it might require more effort. Also, the small flat head is more difficult, because the channel is so thin and shallow. You might need a pen knife to do it.
• Most modules adjust (-) counter clockwise (definitely modern ones), but some vintage ones are the reverse. It is best to make a very small turn first (about 10 degrees), to see how the module reacts. It could very well be that turning the screw and then returning it to the original position may actually cause a slight change from the original gain/loss. You don't want to end up in a crazy back-and-forth chase to find the right position for minimal accuracy drift. So, the less you turn the screw, the better.
• After your first turn of the screw, note the accuracy change across the next 12-24 hours. If time seems to be gaining or losing time more than before, then the required screw rotation is opposite what you did. If you need to adjust the watch some more, try to gauge it by turning a little less that you need to. In the end, you will have some deviation still occurring but hopefully much less than before (within +/- 10sec/mo).
• Once you've made a couple of adjustments, you'll find yourself getting better at gauging the deviation. The closer you are to accuracy, the longer it will take to read the time drift (usually no more than a day). Also, it is possible that environmental changes may affect your accuracy. If you use your watch hiking, snorkeling, cycling, and/or skiing, you'll probably see a slightly greater tendency for accuracy drift. But for a watch not exposed to much change, you'll probably find that one adjustment every couple of years is all you need.
• I found that once I got into doing this, I wasn't satisfied with +/- 10 secs per month and managed to get a couple watches down to +2sec/mo. It was gratifying to achieve that, but in the end really not necessary. If one needs super accurate precision, best to get an atomic sync model.

So, a frustrating loss/gain of time on a G-Shock can be remedied. I recommend trying this out on a "junker" or least liked watch in your collection, just in case you have any trouble along the way... it'll help you get the idea of how the process goes and make it easier for your next one.