WatchUSeek Watch Forums banner

Longines VHP accuracy

40174 Views 122 Replies 14 Participants Last post by  ronalddheld
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.

81 - 100 of 123 Posts
It's a very long thread and one might got confused about the calibration procedures listed in this thread so here are the final (working) versions:

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.

12-steps instruction guide for calibration of the VHP Perpetual Calendar:

1. Remove the battery (leave the crown at position 1 - neutral).
2. Connect needles to the '+' and '-' terminals. (See in diagram on page 19.)
3. Connect the 3V external power supply to the wires that are soldered to these needles.
4. Push the crown to position 0 then release it back to position 1 - that action is needed to switch the watch on - then wait for the date ring to complete its turn.
5. Pull the crown to position 3.
6. With one more needle connected to the '+' of the external power supply; tap the 'C-' or 'C+'terminal X times. (The direction and the number of pulses depend on the current rate of the watch. See the manual for more info.)
7. Push the crown into position 1.
8. Wait 5 seconds.
9. Disconnect power (remove the needles).
10. Insert the battery and close the watch.
11. Push the crown to position 0 to switch the watch on. (The seconds-hand will start to run.)
12. Set time as you would normally do.

Please consider this thread closed and do not add new post to this thread so these final (working) calibration methods could easily be identified by the casual observers.
If needed, further discussion about the calibration of the VHP movements can be continued in a new thread by linking this thread at the beginning of the new one.
See less See more
  • Like
Reactions: 1
I hate to post a new message here based on the above message, but rather than starting a new thread with my comments/questions on the regulating proces, I think it's best to post here to keep the "history" and ppaulusz definitive steps can hopefully be added by a moderator to the first message with a title in red for easy reference ;-)

So here's a summary of my VHP tuning "odyssey" :

1. Got a Flagship VHP in early February

2. After an unexplained 10 second loss "hiccup", it was showing a +45/50 spy rate, way out of spec

3. Snap on back so a massive pain to remove, a watchmaker put me out of my misery (used a box cutter and tapped on it with a small hammer !) and opened it

4. Thanks to the service manual available here (type : 252.611 in "Option 2" and First link), the pics and steps here I knew what to expect

5. Set up problems :
a. Finding a way to power the watch, pull out the crown and tap on the C+ or C- terminal !
b. I used a "scary" contraption made up of a multi-plug power adapter and the needles of my voltmeter! The voltemeter is handy to check that all is being powered as should be, especially the "needle" to tap the C+/C- terminals, here is a picture :

6. Problems with the process :
a. Pushing in the crown to 0 to wake up the watch is easy, pulling out to position 3 not so much, make sure you hear two clicks
b. Another problem with the crown is pushing back to 1 without going to zero since you have to wait 5 seconds in 1 (bolded in the service manual)
c. The remaining problem I haven't figured out is the tapping part. I read the messages above about that but the area to tap wasn't specified. I assume tapping anywhere on the gold connector is good enough? The service manual seems to point to the "black dot" inside the connector...

7. Results : No joy so far, based on some quick testing, I'm at +73spy now (yes I did tap on the C- terminal)...duh! Well I did have to change the original battery as I was getting the EOL (+4 second jumps) signal so maybe I need to figure out the rate with the new battery and adjust it. Not to convinced though...If someone can clarify whether it matters where you tap on the terminals ? Thanks !
See less See more
same here, already tried 3-4 times with no success, mine is +7,7 s/mo
it's a pain so I am not so willing to try again
the only AD Longines service here refused to play with it, and I will take it to another guy, I hope he knows about adjusting and has the tools
my 8F32 Seiko is -25,5 s/y for 43 days on my wrist
Didn't your AD even offer to have it sent back to your local service center ? The watchmaker I was at the other day knew about VHPs but he said they couldn't be adjusted and that he was glad they had been phased out :-(

Do you have any sense as to what steps are causing you difficulties ? Which model do you have ?

I did the process again, this time double-checking everything and tapping a bit longer on the C- and trying to aim at the "black spot"...we shall see.

After starting the watch again, setting it and getting the delay with the "video method" I set it aside and when I picked it up 5 minutes ago I noticed it was doing its EOL (4 second jumps) again...with a battery I put in last night. That CR-2016 battery was still sealed but I've had it for years (about 10) so maybe it's "worn out" too...that or my watch has an issue. Can the EOL signal mean anything else (some type of shorting?) ? If it happens again I'll go out and get a brand new battery to rule out a battery problem.
See less See more
Assistant tool for calibration.....I made this, not pretty, but usable!:-!


See less See more
I just tap on the gold portion. You may have to lengthen you tap duration to get a clear signal to the electronics???? Maybe George can clarify this point.
Thanks, yes I did tap a bit longer during my last try, I'll see what happens, but looking at the posts on the previous pages, it seems Hans had come to the conclusion that a "quick tap" is what the watch wanted.

@vizi - nice setup !
Assistant tool for calibration.....I made this, not pretty, but usable!:-!
Looks like a smart setup - I would guess a 20mm shirt button with 2 holes for the wires and one 'cut' for access to the calibration part ... :-!
Assistant tool for calibration.....I made this, not pretty, but usable!:-!
contact points are not where the wires in the button are, if we look at the picture in the manual
how do you know where to fix them
Very clever!
Now why didn't I think of that?
Simple ways to solve a complex problem. I like it!

Tapping on the golden conductive part is the way to register impulses.
A quick tap is enough.
A scrape could register a few impulses.

The lack of feedback is the main problem here:
No clicks, no beeps, no movement.
The effect of on impulse is only seen a few weeks later.

That's why I had to make my own timing machine. So that I could quickly see what I had done.

I easily made more than a dozen attempts to get anywhere near the perfect setting. Then I made a dozen more for no good reason, simply because I did not account for temperature effects.

The watch can stand it. It won't break because of it.

On the other hand: Try to get a perfect result with a condenser screw.
They are way more finicky.
See less See more
Looks like a smart setup - I would guess a 20mm shirt button with 2 holes for the wires and one 'cut' for access to the calibration part ... :-!
Found,yes it's a 20mm shirt button :-d
Thanks. For some reason my latest attempt seems to have worked better and after 6 hours I'm still spot on using the "video method" that's accurate down to about 0.04 second variations so with my previous 73spy (0.05 in six hours) it would already be's hoping!

Did you ever see the EOL signal other than with a weak battery ?

The point you raise about temperature is interesting since I've observed a variation of about 15spy going from 20c to 30c on my ETA based watches. What temperature did you end up setting it to?
I stopped calibrating when it was at 2-3 s/yr off while (mostly) wearing.
If I wear it continuously it gains 10 ms per day.
A cold night off the wrist slows it down by 15 ms.
A warm night slows it down by 5-10 ms.

So setting it to a slight gain leaves you some room to take it off now and then.
And leaves you some room to 'cheat'.

I have never seen an EOL signal. But there's still time.
contact points are not where the wires in the button are, if we look at the picture in the manual
how do you know where to fix them
The nominations. Wires= red:plus, black:minus


See less See more
Well like Hans once wrote here, it seems my VHP has stopped ignoring me too, the longer taps must have helped ! After almost 24 hours I'm still in the 0.04 uncertainty area (maybe a tad slow) of the video testing (1/25fps), will have to monitor it several days now ;-)

@Hans - how do you measure milliseconds with your video setup ?
@Hans - how do you measure milliseconds with your video setup ?
Well done!
Don't give up.

Quite right. Anything under 40 ms is not visible with the video method.
Video frame analysis is a good way to start.

Now I measure stepper motor pulses.
Down to hundredths of milliseconds now...

My fist attempts are still available in some old threads:
See less See more
Thanks, doesn't look like I'm going to be able to replicate that setup ;-)

It seems to be stabilizing at -20spy so I'll need a few more taps but the other way round now. That's at room temperature though so starting this afternoon I'll put it on my router for 48 hours to simulate a "wearing pattern" and see what happens. Based on what I saw with the other ETA HEQs I own, I could be looking at a 15/20 second variation, consistent with the +/- 10 spy rating. I'll probably go for 4 taps as that would normally bring it to -4spy at room temp and 0 with a bit of wearing.
Assistant tool for calibration.....I made this, not pretty, but usable!:-!
The final version, mirror the process followed. Thus, the perfect :-!


See less See more
After using the button method (thanks vizi, saved me a lot of nerve cells) for adjusting my VHP, it is +0,008 s/3days (2 off 1 on wrist). It will need more time to be conclusive for the success of the adjustment. I used 23 taps to leave it fast instead of 24.
Good to hear but how did you measure 0,007 seconds ?!
81 - 100 of 123 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.