Longines VHP accuracy

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Hans Moleman

Discussion Starter · Sep 24, 2007

Fellow watch nerds!

I have a Longines Conquest VHP watch that runs too fast. Faster than the 10 seconds per year that Longines advertises with. My watch gains 5 seconds per month. Almost a minute per year.
I have been keeping an eye on it, for a few months now, and it is very consistent at gaining one second every 6.5 days.

It might be due for a new battery since it is almost 8 years old. The second sweep still moves every second though.

It has been quite good so far, although I have not paid it as much attention before. I think it used to be one or two seconds out per month.

Anyone else has experiences with a VHP? I read that the rate can be adjusted when serviced. Is that a good idea? Who could do that?

It is a 1999 Conquest Perpetual Calendar Calibre 546. It has 'L1.632.4' inscribed on the back. Not too sure what that stands for.

Cheers
Hans.

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Bruce Reding

· #21 · Oct 2, 2007

Good diagnostics work so far, gentlemen. I hope it works out. (If it does, I'll add this thread to the sticky that discusses this adjustment.)

ppaulusz

· #22 · Oct 2, 2007 (Edited)

Hans Moleman said:
...
9. Wait 5 seconds.
10. Push crown into position 0.
11. Release crown and let it settle into position 1.
12. The date ring turns. The second arm ticks.
13. Pull crown to position 3.
14. Remove needles.
15. Insert battery.
16. Close watch...

I'm back again

:
- change order of steps 9 and 10 (as noted in my earlier post)
- leave step 13 out completely(!!!)

Your procedure should be like this:
1. Remove the battery (leave the crown at position 1 - neutral).
2. Connect needles to the '+' and '-' terminals. As in diagram on page 19.
3. Connect the 3V external power supply to the wires that are soldered to these needles.
4. Pull crown to position 3.
5. With one more needle connected to the '+' of the external power supply; tap the 'C-' patch 14 times.
6. Push the crown into position 1.
7. Wait 5 seconds.
8. Disconnect power (remove needles).
9. Insert battery and close the watch.
10. Push crown to position 0 to let the seconds hand run.
11. Set time as you would normally do.

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Hans Moleman

Discussion Starter · #23 · Oct 2, 2007

Agreed!
Thank you for your tenacity about this.

To make sure that these needles are providing the external power correctly, I will measure some voltages on the watch.

Can't wait to try again!
But first I'll have to wait a few more days to make sure I still have the same rate.

I admire you for your patience with your watch George. It must have taken ages before you knew the corrections worked.

Thank you!

ppaulusz

· #24 · Oct 2, 2007

Hans Moleman said:
Agreed!
Thank you for your tenacity about this.

To make sure that these needles are providing the external power correctly, I will measure some voltages on the watch.

Can't wait to try again!
But first I'll have to wait a few more days to make sure I still have the same rate.

I admire you for your patience with your watch George. It must have taken ages before you knew the corrections worked.

Thank you!

You're welcome, Hans.
As I mentioned earlier we have problems because the whole procedure gets a bit complicated due to the need for an external power supply. Otherwise the calibration procedure is really simple.
My watch was already very accurate: around -4 seconds per year and it needed just a small correction (one impulse) so it took longer to realise that the rate correction went all right. In your case, you should be able to see the result within days.

Hans Moleman

Discussion Starter · #25 · Oct 3, 2007

I am an utter moron. It's official.
The correction needle was connected to the minus of the battery. It should have been the plus.

With all my attention focussed on these power providing needles the obvious escaped me.

My apologies for waisting everybody's time.

The good news is that my next effort will likely have a lot more chances of succeeding. Phew!

I have corrected the rate again, and I look forward to the results.

Sorry about that George!

Eeeb

· #26 · Oct 3, 2007

It was not a waste of time! I got explicit instructions which did not exist before :-! ... every cloud has a silver lining :-d

Actually, it prompted me to get my Perpetual VHP opened up for adjusting... unfortunately I really need 3 hands and have only 2... I'll have to wait until I can get someone to help.

One advantage of my new DC power supply is I'll be able to post the current draw of the movement if it is enough to register.

ppaulusz

· #27 · Oct 3, 2007

Hans Moleman said:
I am an utter moron. It's official.
The correction needle was connected to the minus of the battery. It should have been the plus.

With all my attention focussed on these power providing needles the obvious escaped me.

My apologies for waisting everybody's time.

The good news is that my next effort will likely have a lot more chances of succeeding. Phew!

I have corrected the rate again, and I look forward to the results.

Sorry about that George!

Hans, that is dangerous! You could have killed the electronics of your watch. Lucky you didn't.
However, I agree with Jim: We did not waste time, we learned a lot by going through all the bits and pieces that can make a difference during the calibration procedure. I still believe that your procedure included unnecessary extra steps that can influence the final outcome. Also there were steps in the wrong order and the crown was in the wrong position when you disconnected and reconnected the power. Last but not least your last post shows the importance of paying attention to every details.

ppaulusz

· #28 · Oct 3, 2007

Eeeb said:
It was not a waste of time! I got explicit instructions which did not exist before :-! ... every cloud has a silver lining :-d

Actually, it prompted me to get my Perpetual VHP opened up for adjusting... unfortunately I really need 3 hands and have only 2... I'll have to wait until I can get someone to help...

You are right, Jim, it's a "three-handed" business.

My 11 steps instruction is based on the service manual but includes extra info for us, laymen. Good luck!

mspil

· #29 · Oct 3, 2007

I think the step-by-step instructions listed here are fantastic. Would it be possible for someone knowledgeable to do the same for the non-perpetual VHP conquest. I would find this invaluable, and I am sure there are others who would benefit as well. Thanks in advance!

ppaulusz

· #30 · Oct 3, 2007 (Edited)

mspil said:
I think the step-by-step instructions listed here are fantastic. Would it be possible for someone knowledgeable to do the same for the non-perpetual VHP conquest. I would find this invaluable, and I am sure there are others who would benefit as well. Thanks in advance!

6-steps instruction guide for calibration of the non-perpetual VHP:

1. Open your watch.
2. Pull the crown to position 3.
3. For ETA 255.563: Connect a wire (or needle on the wire) to the '+' of the battery; tap the 'C-' or 'C+' terminal X times then wait 5 seconds then disconnect wire/needle.
3. For ETA 255.561 and ETA 255.472: Tap (with a toothpick) the 'C-' or 'C+' terminal X times.
4. Push the crown into position 1.
5. Close the watch.
6. Set the time as you would normally do.

dwjquest

· #31 · Oct 3, 2007

ppaulusz said:
7-steps instruction guide for calibration of the non-perpetual VHP:

1. Open your watch.
2. Pull the crown to position 3.
3. Connect a wire (or needle on the wire) to the '+' of the battery; tap the 'C-' or 'C+' terminal X times.
4. Disconnect wire/needle.
5. Push the crown into position 1.
6. Close the watch.
7. Set the time as you would normally do.

The only change I would make is to wait 5 seconds between step 4 and 5. The wait of 5 seconds may not be needed as it is not mentioned in some of the other manuals.

The wait period is probably not needed since the battery is installed and the update will not be affected by the removal of adjustment wires (needles).

What do you think, George?

ppaulusz

· #32 · Oct 3, 2007 (Edited)

dwjquest said:
The only change I would make is to wait 5 seconds between step 4 and 5. The wait of 5 seconds may not be needed as it is not mentioned in some of the other manuals.

The wait period is probably not needed since the battery is installed and the update will not be affected by the removal of adjustment wires (needles).

What do you think, George?

You have just answered your own question, David.

You are correct: The wait of 5 seconds is not needed since the battery is not removed during the whole operation.
It can be said after step 5 (it's rather step 5 than 4 as the actual calibration is completed after the crown is pushed back to position 1.) that: wait for at least 5 seconds if you are about to remove the battery - but why on earth would anyone decide to remove the battery in a situation like that?
In case of a need for battery change, it should be carried out before the calibration procedure.

Hans Moleman

Discussion Starter · #33 · Oct 3, 2007

Maybe we're not there as yet.

My watch was 0.03 second slow after I adjusted the rate.
I was a bit slow pushing in the crown! :-d
And after 17 hours of operation, it is 0.06 second fast.

That would equate to 1 second gain every 6 days. Which means no change in the rate.

Measured by video with a NTP calibrated computer clock as reference.

It's a bit premature, to draw conclusions on that so I'll make some more measurements the next few days.

ppaulusz

· #34 · Oct 3, 2007

Hans Moleman said:
Maybe we're not there as yet.

My watch was 0.03 second slow after I adjusted the rate.
I was a bit slow pushing in the crown! :-d
And after 17 hours of operation, it is 0.06 second fast.

That would equate to 1 second gain every 6 days. Which means no change in the rate.

Measured by video with a NTP calibrated computer clock as reference.

It's a bit premature, to draw conclusions on that so I'll make some more measurements the next few days.

Indeed, it is a bit premature to draw conclusion.
Which guide did you follow: 21-steps (see post #18) or 11-steps (see post #22 ) or something else?

Hans Moleman

Discussion Starter · #35 · Oct 3, 2007

These were the steps I used last:

1. Remove the battery (leave the crown at position 1 - neutral).
2. Connect needles to the '+' and '-' terminals. As in diagram on page 19.
3. Connect the 3V external power supply to the wires that are soldered to these needles.
4. Pull crown to position 3.
5. With one more needle connected to the '+' of the external power supply; tap the 'C-' patch 14 times.
6. Push the crown into position 1.
7. Wait 5 seconds.
8. Disconnect power (remove needles).
9. Insert battery and close the watch.
10. Push crown to position 0 to let the seconds hand run.
11. Set time as you would normally do.
Cheers
Hans

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ppaulusz

· #36 · Oct 3, 2007 (Edited)

Hans Moleman said:
These were the steps I used last:

1. Remove the battery (leave the crown at position 1 - neutral).
2. Connect needles to the '+' and '-' terminals. As in diagram on page 19.
3. Connect the 3V external power supply to the wires that are soldered to these needles.
4. Pull crown to position 3.
5. With one more needle connected to the '+' of the external power supply; tap the 'C-' patch 14 times.
6. Push the crown into position 1.
7. Wait 5 seconds.
8. Disconnect power (remove needles).
9. Insert battery and close the watch.
10. Push crown to position 0 to let the seconds hand run.
11. Set time as you would normally do.
Cheers
Hans

OK, I believe these are the right steps according to the manual and common sense. By common sense I meant to indicate that I compared the service manual's guide for calibration of the similar but 1.55V powered ETA 252.511 movement (it does not need external power supply for the calibration) to the service manual's guide for our ETA 252.611 and did not find anything that would contradict the 11-steps guide. On the other hand the comparison actually confirmed for me that the 11-steps guide is the right one.
Well, that is the theory which should be supported by experimental evidence and that is where we have problem.
In the case of my watch I only needed just one impulse given to the "C+" terminal. I have reported that it was a success. I came to this conclusion by checking the watch (3-4 weeks after the rate adjustment) against the atomic-time reference on the net (as I usually do). That time I did not take much note of the fact that in Central Europe we experienced extremely high (close to 40°C) temperature for weeks. I hardly wear the watch so it's been subjected to temperature changes without "body-thermocompensation" or air-conditioning. Its built-in thermocompensation should take care of most but the really extreme temprature changes. Having said that, now I wish I had to correct more than just that one impulse because it would have been easier to measure any rate change with greater adjutment. If nobody else can repeat my success(?) (calibrating the ETA 252.611 movement) in the next couple of weeks then I will make a new attempt to adjust the rate on my Longines: this time I would go for + or - 10 impulses (equals to around + or - 40 seconds per year) just to see that it really works. In the meantime, I pray that someone will save me from the "forced" calibration procedure.

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Bruce Reding

· #37 · Oct 3, 2007

ppaulusz said:
OK, I believe these are the right steps according to the manual and common sense. By common sense I meant to indicate that I compared the service manual's guide for calibration of the similar but 1.55V powered ETA 252.511 movement (it does not need external power supply for the calibration) to the service manual's guide for our ETA 252.611 and did not find anything that would contradict the 11-steps guide. On the other hand the comparison actually confirmed for me that the 11-steps guide is the right one.
Well, that is the theory which should be supported by experimental evidence and that is where we have problem.
In the case of my watch I only needed just one impulse given to the "C+" terminal. I have reported that it was a success. I came to this conclusion by checking the watch (3-4 weeks after the rate adjustment) against the atomic-time reference on the net (as I usually do). That time I did not take much note of the fact that in Central Europe we experienced extremely high (close to 40°C) temperature for weeks. I hardly wear the watch so it's been subjected to temperature changes without "body-thermocompensation" or air-conditioning. Its built-in thermocompensation should take care of most but the really extreme temprature changes. Having said that, now I wish I had to correct more than just that one impulse because it would have been easier to measure any rate change with greater adjutment. If nobody else can repeat my success(?) (calibrating the ETA 252.611 movement) in the next couple of weeks then I will make a new attempt to adjust the rate on my Longines: this time I would go for + or - 10 impulses (equals to around + or - 40 seconds per year) just to see that it really works. In the meantime, I pray that someone will save me from the "forced" calibration procedure.

Excellent example of clear thinking, George. The forced calibration, while painful, would be a clear confirmation if necessary. Do David's positive results support the validity of your procedure?

Hans Moleman

Discussion Starter · #38 · Oct 3, 2007

Don't worry George!
I enjoy doing it.
You have been a source of inspiration for me.

There is one more step that I would like to slip in somewhere. And I believe it makes a lot of sense.
It is step 3B as outlined on page 16. "Press the crown briefly; the watch will begin to work ..."

I suspect that connecting an external power supply, and for that matter inserting a new battery will not get this watch going. It needs this quick push on the crown for the watch to get to work.

So the corrections I made in my last effort were made to a watch that is asleep. Or at least not switched on.

And another guess: The quick push on the crown to get the watch going, was meant so that the watch could be stored without draining the battery. To store it until it was time to be sold.

In my last effort I made sure that the watch was connected to the external power supply by measuring the voltage as in Fig 1. on page 15. I would have liked to just switch it on, by pressing the crown briefly and then pulling the crown to position 3, and start the corrections.

What do you think? Do you remember anything about quickly pressing the crown to get the watch going while on external power?

Cheers
Hans

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ppaulusz

· #39 · Oct 3, 2007

Bruce Reding said:
Excellent example of clear thinking, George. The forced calibration, while painful, would be a clear confirmation if necessary. Do David's positive results support the validity of your procedure?

David is yet to calibrate a watch that needs external power supply during the procedure. He had great results with his other watches. We know that the external power supply makes the procedure much more complicated (for us laypersons). So I look forward to David's attempt to calibrate his Longines (ETA 252.611).

ppaulusz

· #40 · Oct 4, 2007

Hans Moleman said:
... There is one more step that I would like to slip in somewhere. And I believe it makes a lot of sense.
It is step 3B as outlined on page 16. "Press the crown briefly; the watch will begin to work ..."

I suspect that connecting an external power supply, and for that matter inserting a new battery will not get this watch going. It needs this quick push on the crown for the watch to get to work.

So the corrections I made in my last effort were made to a watch that is asleep. Or at least not switched on.

And another guess: The quick push on the crown to get the watch going, was meant so that the watch could be stored without draining the battery. To store it until it was time to be sold.

In my last effort I made sure that the watch was connected to the external power supply by measuring the voltage as in Fig 1. on page 15. I would have liked to just switch it on, by pressing the crown briefly and then pulling the crown to position 3, and start the corrections.

What do you think? Do you remember anything about quickly pressing the crown to get the watch going while on external power?

Cheers
Hans

Hans, your theory about step 3B makes sense. It might be the missing link. Yes, it can happen that the watch has an "on switch" (crown position 0) for safety reason and for avoiding draining of the battery in the shop (as you mentioned).

Honestly, I can't recall pushing the crown into 0 position before pulling it to position 3 during the calibration procedure. Not on purpose for sure. Accidently? It's a long shot... I doubt.

However, one thing is almost certain to me: we run out of options or logical (my logic) alternatives. It's either my original 11-steps procedure or it's modified (by you) version with the added step 3B. The more I think about it, the more I like your thought about the extra step.|> I'd say, give it a go!
Good luck (you will need it)!

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