Wandering Asian 7750 Hour Totalizer Hand

[freddy333]

The hour totalizer hand (subdial at 6) is creeping around the subdial very slowly when the chrono function is OFF (it works normally when the chrono is ON). In fact, you can see it just to the right of the 12 in this photo, which was taken about 20 minutes after the chrono had been reset back to the null position (all 3 chrono hands pointing to the 12 on their respective scales)

The longer the watch runs, the further around the subdial the hand will slowly move. It resets back to 12 without any problem every time. Trouble is that it also starts moving again within 15 or 20 minutes every time.

Any idea what the problem is and, more importantly how to fix it?

[Shundi]

I seem to remember it has something to do with a lever in the escapement being permanently frozen in one position. Try searching around the forums or looking up The Zigmeister, I think he's good for fixing issues like that...

ND

[freddy333]

I did a search before posting, but was unable to find anything relevant. Thank you anyway.

[z80]

I have 2 Tag Carreras with A7750's that have the same issue, I just push the chrono reset every once in a while.

[freddy333]

Yes, that is true and I could keep doing that. But I am neurotic & my minimum requirement for wearing any watch is that it function properly and keep reasonable time. I would rather find out what the problem is and fix it than to keep having to reset it every 30 minutes. But I understand where you are coming from and it makes sense.

I have a feeling it is a relatively simple thing to correct. Ziggy will probably chime in tomorrow. Thank you though.

[RWG Technical]

There are a number of reasons this happens.

1. Isolate the problem by first taking the movement out of the case, and monitoring it. If the 12 hour doesnt' move with the chrono off when the movement is out of the case - you have a pusher issue, it's touching the lever and disengaging the brake arm.

2. If you have a movement spacer ring (doubtful on a Daytona), and the hand moves out of the case, remove the ring, in case it's pressing on the lever.

3. If the hand moves when the movement is out of the case, you have to take the dial and hands off, and the top bridge off to try and find out why. It could be a defective chrono reset arm, or the plastic brake lever, or too much friction on the 12 hour wheel clutch etc...

My guess is No 1 is the most likely.

Hope this helps.

RG

[freddy333]

Initially, I thought the pusher pin was the culprit, so I filed the pin down, but that did not fix it. So I think you are probably right about there being problem with the brake lever (if it was the reset arm, I would think the chrono second & minute counters would continue running also).

Thanks, Zig.

[freddy333]

The problem turned out to be that the lever itself was bent.

Not only was the dial on this watch filthy (there were literally crumbs all over the dial & the hands had such a think layer of *greasy* fingerprints on them that I originally thought they were made out of white plastic with a worn coat of chrome paint on top.....until I started rubbing them with Rodico), but I blew a dust cloud out of the movement. I am amazed that this thing even runs. I wish I had taken some pictures of the inside of this thing before I cleaned it. Lack of QC is one thing, but to be assembling watches while you are eating your lunch.......Sheesh......

But after tweaking the regulator a bit, everything seems to be running fine now. I am even beginning to toy with the idea of capping this one off with one of those sparkling, beveled gen T21s. Funny how the addition of a set of asymmetrical pushers can give an otherwise average-looking rep the unmistakable air & presence of the real thing.

(Picture taken before hour totalizer hand was fixed)

[llsteve80]

Glad you got it fixed, those are nice watches you have there. I probably would have bought a daytona by now if it wasnt for all of the little things that happen with them. Where did you get that one with asymmetrical pushers anyway? Looks like the NTDtrading case that used to sell for $1200 on the bay. Very nice.

[freddy333]

There are a number of reasons this happens.

1. Isolate the problem by first taking the movement out of the case, and monitoring it. If the 12 hour doesnt' move with the chrono off when the movement is out of the case - you have a pusher issue, it's touching the lever and disengaging the brake arm.

My guess is No 1 is the most likely.

Hope this helps.

RG

Ziggy -- Apparently, I was premature in pronouncing the job done. After reassembling the case, the hand began to move again. But the good news is that I just discovered the real source of the problem, which is related to item 1 above. The lever, itself, is bent causing it to come into contact with the inside of the case when the movement is reinstalled. I think you can see the way the lever sticks out beyond the outer boundary of the movement in these pictures

Any recommendations on how to unbend (or bend) the lever without disassembling the movement? I was thinking that I could use a Dremel to grind down the edge of the lever that is coming into contact with the case, but I am worried that either the pusher pin might not have enough of a flat surface to operate correctly or, more likely, that the metal dust & shavings from the grinding would get into the movement.

[freddy333]

Glad you got it fixed, those are nice watches you have there. I probably would have bought a daytona by now if it wasnt for all of the little things that happen with them. Where did you get that one with asymmetrical pushers anyway? Looks like the NTDtrading case that used to sell for $1200 on the bay. Very nice.

Thank you, but all 3 have asymmetrical pushers (the button pushers of the 6239 & 6241 (the watches at far left & right) make it difficult to see because of the viewing perspective). The 6239 & 6241 are Valjoux 72-powered DWs, which use the same base movement that Rolex originally fitted into the vintage Daytonas (use the Search function to learn about DW Daytonas). The 6263 in the center is somewhat unique due to its being powered by an Asian 7750 with the correct asymmetrical pusher arrangement (most 7750s have symmetrical pushers, which are inaccurate for vintage Daytonas). Unfortunately, I cannot reveal the source of this watch just yet, but I should be able to provide more details soon.

____________

UPDATE -- After rethinking the situation, I decided that it would be foolhardy to do any grinding or bending of the lever, at least while it is contained within the movement. So, instead, I turned my dremel to the case and ground out a small semi-circular area just a mm away from the path of the pusher pin, which is where the lever is coming into contact with the case. Because the pusher is in very close proximity, I had to be somewhat conservative in the amount of metal I removed. But the lever is definitely coming into contact with much less of the case now, but not quite sure it is now able to fully-extend to its OFF position. So I just reinstalled the movement (held in place by the stem only....no movement clamps just yet) and will let it run for 30 minutes to see if that worked. If not, I will try removing a bit more metal & then retest. I will keep updating here in case someone else has this problem in future.....

____________

30-MINUTE UPDATE -- All is well, so I reinstalled both case clamps and loosely fit the caseback. If all is still well 30 minutes from now, I will finally, and officially, pronounce the problem solved.

[RWG Technical]

Sounds like you figured it out.

For reference, the lever is supposed to be out from the movement that little bit, which is why the spacer ring, or in your instance the case, can be the cause of the problem.

Great job.

RG

[freddy333]

Sounds like you figured it out.

For reference, the lever is supposed to be out from the movement that little bit, which is why the spacer ring, or in your instance the case, can be the cause of the problem.

Great job.

RG

I am chuckling to myself as I write this and the reason for the giggles is because I feel very stupid. After the watch came through the last round of testing with flying colors and I was about to put this baby to sleep, I tightened the caseback (not overtight, just snug) and the hand started to crawl again (like my skin). The problem is due to the DW caseback pressing on the lever once the caseback is screwed down all the way. I did not realize it when I swapped the DW caseback for the original (the original caseback is too tall), but the side wall of the DW caseback is almost 3 times as thick as the original caseback and so it is coming into contact with the lever somewhere along its path. I am confident this is the problem because I have spent the past 2 hours loosening, testing, tightening, testing, loosening, testing, tightening, testing, etc. and the hand only does its crawl when the caseback is tightened. It stays perfectly still when either the original caseback is installed or the DW caseback is only loosely fit.

So I have been going at the inside wall of the DW caseback with my Dremel, trying to reduce the sidewall thickness to the point where it will clear the lever. After seeing how much more accurate the watch looks with the lower profile DW caseback, there is no way I could ever go back to the too high original. Here is a comparison of the 2 casebacks (the accurate DW is on the right, original (too tall) caseback on the left)

(You can see where I have started to Dremel (thin) the sidewall of the lower profile DW caseback (on right) near the CRS inscription)

_________

FINAL UPDATE — After reassembling the watch with the dremeled-out DW caseback, the watch has been running flawlessly for more than an hour & the hour totalizer hand has not budged from its proper null (OFF) position once. Problem solved (for real this time). Thanks to all who provided help.

[llsteve80]

Unfortunately, I cannot reveal the source of this watch just yet, but I should be able to provide more details soon.

Can't wait, I just may spring for something like that, maybe even go nuts and get one where daytona is on the top..... All I find for parts is ntd trading cases for $1150! There are others for about 800 too, but for this price I would like to just buy something thats all put together.

It's crazy how something as simple as swapping a caseback can cause so much trouble.

[freddy333]

Can't wait, I just may spring for something like that, maybe even go nuts and get one where daytona is on the top..... All I find for parts is ntd trading cases for $1150! There are others for about 800 too, but for this price I would like to just buy something thats all put together.

It's crazy how something as simple as swapping a caseback can cause so much trouble.

Yes, tell me about it...... On second thought, keep it to yourself. I think I have had enough casebacks for one night.

But I am curious about your comments above......Although the watch in the middle in this picture is not for sale, are you saying you would be willing to pay $800 for one of these 7750-powered Daytonas if it was already assembled?

[freddy333]

3. If the hand moves when the movement is out of the case, you have to take the dial and hands off, and the top bridge off to try and find out why. It could be a defective chrono reset arm, or the plastic brake lever, or too much friction on the 12 hour wheel clutch etc...

Ziggy - I am trying to repair another secs at 6 Asian 7750 that has the same problem my secs at 9 7750 had (the hour totalizer continues to move when the chronograph is off). In this case, the problem continues when the movement is out of the case, so I know I am dealing with one of the components you mentioned above. I have removed the top plate of the movement & stopped here

I know I need to remove the next plate/bridge as well as all of the gears here, but I wanted to check to see if there are any gotchas before I proceed? That is, can I just lift off each of the 8 gears and then remove the 3 screws & lift off the plate? And is reassembly just a reversal of the removal procedure? And just to be sure, am I correct that with these movements none of these gears or jewels gets any oil?

______________

As an aside - I have found that every one of these secs at 6 7750s have very 'twitchy' seconds hands. That is, instead of a 'sweeping' motion as the hand moves around the seconds subdial, the movement is quite erratic & stuttery.

I know that using oil to lubricate the additional gearing for these relocated running seconds hands adds additional drag and friction, adding to the already overloaded movement. But I am wondering if you ever considered (or tried) using powdered graphite to lubricate the extra gearing since, being a dry (very fine powder) lubricant, it should not add as much (if any) additional drag as a liquid oil & might be useful in resurrecting some of the prematurely dead Daytonas?

[llsteve80]

If people are going to be getting this watch, this should be a sticky. I re-read it now, and I have the same deal going on with my caseback. Who knows when I'll have a chance to work on it though, time is my enemy lately. I am currently testing my watch without caseback. Apparently I was also premature when I declared mine to be running perfectly.

On a side note, for those interested in this watch, it is worth it to me, and I'm sure to freddy as well. It is a very economical solution to the v72 powered watches, and way more accurate than anything else out there. It seems the stems for the 3 and 9'oclock subdials are only about 1mm further apart TOTAL than the v72, so unless you know, you would probably miss it. I'm sure this would do quite a number on the casual observer. Most people who know about the gen may have not even seen one in person anyway. The only external difference in the case is about .75mm or so shallower rehaut.

[freddy333]

The components that control the chrono reset on Asian 7750s are VERY finicky. So if you begin experiencing the hour totalizer 'creeping hand' problem (the hand keeps moving when the chrono is OFF) when the movement is OUT of the case, it is probably being caused by the brake lever spring having come out of position (this can happen if you press the reset pusher too hard or if the reset pusher lever accidentally gets pressed while the movement is out of the case). This picture shows the offending spring & its correct location (if the spring is in its correct position, you will be able to see the outside 'leg' of the spring through the side of the movement)

I incorrectly labeled the white nylon part in the picture as a clutch -- I meant to say (hour totalizer) brake. When the spring is set correctly, it applies pressure against the brake lever, which keeps the brake (the white, upside-down v-shaped part in the picture) pressed against the hour totalizer gear. When the spring jumps out of position (as it is in the picture), the brake 'floats' and the hour totalizer gear turns the hand when it is not supposed to.

[ryaku]

There are a number of reasons this happens.

1. Isolate the problem by first taking the movement out of the case, and monitoring it. If the 12 hour doesnt' move with the chrono off when the movement is out of the case - you have a pusher issue, it's touching the lever and disengaging the brake arm.

My guess is No 1 is the most likely.

Hope this helps.

RG

Hi Rob,

this is what happened to my watch.

I just uncased the movement and problem is gone.

It seems like the pusher is too long.

Could you please have a look at the pics below and tell me your opinion?

Is the pusher supposed to be shorter?

Also, I'm really scared my watch might lose a pusher suddenly (it has happened to many IWC Gst, I'm more than sure you're aware of that).

Is there a method to avoid this? How can i secure the two pushers?

Thanks a lot

R.

[Ephry73]

Freddy,

I am now experiencing a very similar issue with the 6239. Was the spring correction a solution to the problem?

E

[ryaku]

Same here, my movement runs great the only issue is the subdial hand at 6-o-clock... annoying to say the least

I've got no balls to dismantle the movement and fix it, i'm afrais i wouldn't be able to complete successfully such a complicate task....it's not like fixing a keyless work on a 2824

[Ephry73]

Also, @ Freddy, have you had issues with the pump pushers not holding their own under water? Just curious.

E