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.

1 - 20 of 123 Posts

artec

· #2 · Sep 24, 2007

Hans Moleman said:
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.

I daresay he'll respond himself but ppaulusz has posted in a recent thread describing how he adjusted his VHP. It was within the last couple of weeks so you could probably find it if you searched backwards. I followed up with him (because I've just bought an NIB VHP myself and he was kind enough to e-mail me the ETA Service manual on the watch. I've read the instructions on making the adjustment and it doesn't sound all that difficult though I haven't tried it. I've only had the watch two days so adjustment might be a little premature.
If ppaulusz doesn't offer help, I could probably e-mail you the book. Send me a pm if you want me to, but don't expect any detailed advice for obvious reasons!

Eeeb

· #3 · Sep 24, 2007

You will find a full thread on this topic in the meritorious threads sticky at the top of the page... full instructions are therein contained!!

You can do the adjustment yourself if you can pop off the back, have some spare wires, a 3 volt battery or power supply and have three hands :-d ... check the thread.

Hans Moleman

Discussion Starter · #4 · Sep 24, 2007

Excellent!
Looks like I came at the right time.

I've got all I need to have a go now.
Thanks for all the pointers.

ppaulusz

· #5 · Sep 24, 2007

Good luck, Hans!

The Boys already told you everything you have to know. The Longines caliber L.546 is in fact an ETA 252.611 Thetmoline caliber. The calibration is not difficult but care should be taken! First make sure you know what needs to be done and do one or two demo runs without touching the terminals. Then you can do the real thing by following the guide in the service manual to the letter!

Bruce Reding

· #6 · Sep 24, 2007

Let us know how it goes, Hans!

Hans Moleman

Discussion Starter · #7 · Sep 24, 2007

Now that I have read the thread on watch regulation, I have to thank you and other members for sharing your experiences so freely!
Especially the link to the ETA calibre is invaluable.

I know now that I am not the only one with a VHP watch that is out of spec. Not because of faulty workmanship, but because of lack of adjustment.

A few points remain:
- I need to find a helpful jeweler who can open the case.
- This watch is worn continuously. Do you recommend that I keep wearing it, while I
regulate it?

Thanks
Hans.

Eeeb

· #8 · Sep 25, 2007

Hans Moleman said:
...
- This watch is worn continuously. Do you recommend that I keep wearing it, while I regulate it?

One of the wonderful things about ETA thermocompensated movements is it makes no difference how much you wear them... They do not rely on any sort of wrist time to keep them accurate.

It does help to avoid extreme temperatures... at very high and very low temperatures the compensation needed is quite high and inaccuracy can increase.

I'd just use the watch as you would normally. But if you are planning a trip to the South Pole while you are regulating it, I'd keep it inside the sleeve of the parka :-d

Eeeb

· #9 · Sep 25, 2007 (Edited)

Hans Moleman said:
...

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.

Longines has a website that contains a wealth of data.

On it we can see the L546 is a quartz resonator, 25.60mm in diameter with a thickness of 5.00 mm, uses a CR2015 Renata battery which produces a specified power reserve of 120 months, has a stated accuracy of +- 1 second/month and uses a base calibre of an ETA 252.611 which has 11 jewels.

As you can see, Longines is quite conservative in it's specs.

The model numbering reference shows the following for L1.632.4:
"L" -- it's a Longines!
"1" -- it's in the "1" family (I think this is the Conquests)
"6" -- it's a man's sized watch
"32" -- a consecutive number assigned to identify models (I think this is the Perpetual VHP)
"4" -- case material = stainless steel

There are two more possible numbers, xx.y to identify a very specific model. The xx shows the dial and the y shows the strap.

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artec

· #10 · Sep 26, 2007

Eeeb said:
Longines has a website that contains a wealth of data.

On it we can see the L546 is a quartz resonator, 25.60mm in diameter with a thickness of 5.00 mm, uses a CR2015 Renata battery which produces a specified power reserve of 120 months, has a stated accuracy of +- 1 second/month and uses a base calibre of an ETA 252.611 which has 11 jewels.

As you can see, Longines is quite conservative in it's specs.

The model numbering reference shows the following for L1.632.4:
"L" -- it's a Longines!
"1" -- it's in the "1" family (I think this is the Conquests)
"6" -- it's a man's sized watch
"32" -- a consecutive number assigned to identify models (I think this is the Perpetual VHP)
"4" -- case material = stainless steel

There are two more possible numbers, xx.y to identify a very specific model. The xx shows the dial and the y shows the strap.

I have a VHP Conquest with the number L1 636.4 on the back, as well as a number as long as a car's VIN (the serial number from the warranty card). My L number is the same as yours except for the second 6 replacing your 2. Production year, maybe?

From the Longines importer, I understand that the black-faced model had a number of L 16364566. The first 6 characters are the same as those on the back of my watch. The model number on my warranty card is L 16364966 and mine has a blue face, so the ante-penultimate number is probably the dial color, as you suggest. Mine has an integral bracelet and if it came with a strap, the case would have have different lugs....... maybe the last two identify case and strap? Mine is the first I've ever seen, so I have no idea whether they were available on straps.

ppaulusz

· #11 · Sep 26, 2007 (Edited)

artec said:
...Mine is the first I've ever seen, so I have no idea whether they were available on straps.

Every Conquest VHP from the first model in 1984 (dual-oscillator) to the last production series with perpetual calendar around 2002 had integrated metal bracelet (stainless steel or titanium).
From 2002 till 2006 the Flagship models were fitted with the VHP perpetual calendar movement and those ones were available with stainless steel bracelet or alternatively leather straps

Hans Moleman

Discussion Starter · #12 · Sep 26, 2007

I really would like to get this watch to run a few seconds off per year.

First hurdle; getting the back off and keeping it off so that I can adjust it a few more times until I am satisfied with the rate.
I tried a simple trick with a piece of inner tube. The rubber is quite soft and sticks well to the embossed back. Pressing down with my fingers and turning at the same time, the back slowly turned. You can only tell by the orientation of the embossing that it is turning though. No chisels required!

Once open its inner guts looked exactly like on one of the photographs. Only a lot smaller!
I soldered wires to three needles. Two for the power supply and one for the pulses. A washing peg kept the wires attached to the battery that had to come out and now served as an external power supply.

A few deep breaths and off it went. Balancing the two power supply needles with my left hand, I was dishing out the pulses with my right. 14 taps later I was happy it was all over and removed the power.

Battery back in, and I was relieved to see that the patient had not died. The date wheel was turning, which stopped after it had done its thing and the second arm was ticking away.

That was two days ago, and I don't think it has made a difference. But reading the manual again, I missed two instructions. The part of pushing the crown in after the tap adjustments, and waiting for 5 seconds before disconnecting the power. I am not too sure yet how I'll push in the crown while balancing the two power needles.

I might construct a small rig so that I don't have to hold these power needles all the time.

Anyway. I'll have to wait a week, to see if it is off to its usual 1 second gain per week. If that is the case I know for sure that I did not make any adjustments and I can repeat most of the above.

I don't like doing it, but I like it that it can be done.
Cheers.
Hans.

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ppaulusz

· #13 · Sep 27, 2007 (Edited)

Hans Moleman said:
...I don't like doing it, but I like it that it can be done...

Exactly my sentiment!
Congratulations and let us know about the results!:-!
The need for external power supply makes it more cumbersome for the ones with 3V lithium battery.

Hans Moleman

Discussion Starter · #14 · Oct 2, 2007

Very little progress so far after the second attempt.
The good news is that the watch is so far out of spec that its quickly obvious that the regulation hasn't worked. Every cloud has its silver lining!

The last effort I made sure that the external power supply works. The clock is ticking when the crown is in 'position one' and stops when in 'position three'.
The only thing I can think of now, is that I administer my correction pulses too quickly. I pulsed at two pulses every second or so. I have 14 pulses to go through, so obviously I was in a hurry.

I guess the little computer inside has to differentiate between bounces and proper pulses.
What do you think, do I need to take my time with these pulses?

Cheers
Hans.

Eeeb

· #15 · Oct 2, 2007

I doubt there is 'debounce' software. However, there is a clue in the statement that you need to make sure you leave the power on for 5 seconds after entering the correction count. It is quite possible the cpu does not 'strobe' the register (that is, does not record that a pulse took place) except every 5 seconds. So I would try making each pulse last longer with a bit more than 5 seconds between pulses...

George only needed to do one pulse to correct his VHP. I only just got an external DC power supply and haven't tried it yet. You are another pioneer -- you can always tell them by the arrows sticking out of their back! :-d

Good luck.

ppaulusz

· #16 · Oct 2, 2007

Eeeb said:
I doubt there is 'debounce' software. However, there is a clue in the statement that you need to make sure you leave the power on for 5 seconds after entering the correction count. It is quite possible the cpu does not 'strobe' the register (that is, does not record that a pulse took place) except every 5 seconds. So I would try making each pulse last longer with a bit more than 5 seconds between pulses...

There is no harm to wait 5 seconds between impulses but it is not necessary. Let's not forget that the ETA technical manual details the steps and includes all the info needed. It does not specify 5 seconds periods between impulses. Check the manual of the ETA 252.611's sibling, the ETA 252.511! These movements are almost identical. The only difference is the battery. The manual of the ETA 252.511 does not specify any period of time between impulses either.

ppaulusz

· #17 · Oct 2, 2007

Hans Moleman said:
Very little progress so far after the second attempt.
The good news is that the watch is so far out of spec that its quickly obvious that the regulation hasn't worked...

OK, so the very little progress in fact means no progress at all. Since you have checked your power supply and it did work there is only one explanation left for the failed attempt: There is something wrong with your procedure.
Would you mind to describe your procedure in details (step by step)? Please include everything you do during the procedure so we can see where the problem is. I'm sure we can come up with the right solution.

Hans Moleman

Discussion Starter · #18 · Oct 2, 2007

The 'little progress' is an example of British understatement. It is supposed to be funny.
Here are the steps. The more eyes the better.

1. Put watch in cradle. It locks it into place.
2. Open back.
3. Put crown in position 3.
4. Remove battery.
4. Connect needles to the '+' and '-' terminals. As in diagram on page 19. The cradle holds these needles into place. I still have two hands available.
5. Connect the battery (that came out) to wires that are soldered to these needles.
6. Confirm that the watch runs on the battery via the needles by pushing the crown into position 0. Once released, it flips back to position 1, the date ring turns, then ticks normally. It will not run until pushed into the 0 position.
7. Pull crown to position 3 again.
8. With one more needle connected to the '+' of the battery; tap the 'C-' patch 14 times.
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.
17. Push crown to position 0.
18. Release crown. It will settle in position 1.
19. The date ring turns. The second arm ticks.
20. Adjust time.
21. Check rate.

I don't really know what happens when the date ring turns. I am too slow with turning the cradle over.

Thanks guys!

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ppaulusz

· #19 · Oct 2, 2007

Hans Moleman said:
The 'little progress' is an example of British understatement. It is supposed to be funny.
Here are the steps. The more eyes the better.

1. Put watch in cradle. It locks it into place.
2. Open back.
3. Put crown in position 3.
4. Remove battery.
4. Connect needles to the '+' and '-' terminals. As in diagram on page 19. The cradle holds these needles into place. I still have two hands available.
5. Connect the battery (that came out) to wires that are soldered to these needles.
6. Confirm that the watch runs on the battery via the needles by pushing the crown into position 0. Once released, it flips back to position 1, the date ring turns, then ticks normally. It will not run until pushed into the 0 position.
7. Pull crown to position 3 again.
8. With one more needle connected to the '+' of the battery; tap the 'C-' patch 14 times.
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.
17. Push crown to position 0.
18. Release crown. It will settle in position 1.
19. The date ring turns. The second arm ticks.
20. Adjust time.
21. Check rate.

I don't really know what happens when the date ring turns. I am too slow with turning the cradle over.

Thanks guys!

Great stuff, Hans! Sorry, I tried to be funny too in the erlier post about the very little progress... ;-)
Anyhow, I think I know the solution, thanks to your very detailed post about your procedure.
It seems to me that steps 9 and 10 are in the wrong order. According to the service manual:
"After correcting the rate push the crown back to position 1 (neutral).
Wait 5 seconds before disconnecting the external power supply."

Also, try to push the crown back to position 1 instead of all the way to position 0. Even if it goes all the way back to position 0, it should be immediately released so it stays on position 1.
The last paragraph is just me being picky as probably you have done it the same way so I just want it to be confirmed.
The important part is the quote from the service manual!

Good luck and let us know, please!

ppaulusz

· #20 · Oct 2, 2007

Hans Moleman said:
...
1. Put watch in cradle. It locks it into place.
2. Open back.
3. Put crown in position 3.
4. Remove battery.
4. Connect needles to the '+' and '-' terminals. As in diagram on page 19. The cradle holds these needles into place. I still have two hands available.
5. Connect the battery (that came out) to wires that are soldered to these needles.
6. Confirm that the watch runs on the battery via the needles by pushing the crown into position 0. Once released, it flips back to position 1, the date ring turns, then ticks normally. It will not run until pushed into the 0 position.
7. Pull crown to position 3 again...

One more thing, Hans: I've checked the service manual because I felt that your procedure is somewhat different than mine even from the very start. It might not be a real issue but I'd like to make a note that the service manual indicates that during battery replacement the crown should be in position 1 (see page 13 or 16 - depending which pdf file you read). In your procedure the crown is in position 3 when you take the battery out and it is still there when you connect the external power supply (see your procedure from step 3 to step 6). Try to do it according to the service manual as it might make a difference.

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