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Which eta movement for GMT PAM?


xtuner

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The Gen uses the OP VIII caliber, which is a ETA 7750 modified with a GMT module. If you could get your hands on a ETA 7754, you should be able to swap it out. I know the 7754 is intercheangable with the other ETA 775X movements. The question that I can not answer is if the hands from a Asian clone will fit a ETA movement.

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i have two vajoux 7754 gmt movements in my stock.

two years ago i had the same idea to built-in this movement in one of my gmt pam.

but it's not possible.

the gmt rep pams have inside the old asia7750b1 movement.

it has a taller measurement as the gen ones and the inner measurements of the cases are deeper constructed.

the asia7750b1 have on top an additional ring, that's why also the date wheel is sunken.

so my watchmaker thought to use and to install the asia upper metal-plate with the distance-ring on the swiss 7754.

result, it did fit.

but all swiss hand gears are too short, because the asia upper-plate with distance-ring together with the swiss 7754

has the asia measurement for the gmt case, but too tall for the shorter swiss hand gears.

to use the asia hand gears in the 7754 is not recommendable. then you don't have the swiss effect anymore.

some talkings with the eta production chief brought the result, there is no possiblity to get longer hand gears for the 7754 gmt movement.

eta produce the 7754 only with h1 hand gear length.

for a special custom order the quantity has to be minimum 10.000 sets.

so for me this gmt project to swap a 7754 was dead.

ca. 6 weeks ago i've started a second attempt to get information about the new asia ultimate gmt cases in terms of the inner measurements.

in connection with precious time i started the request direct to the maker of the ultimate gmt pams.

also a technical drawing was sent to the maker to get this information about the inner measurements.

the result, same old measurements which is too deep for the swiss 7754 gmt.

so also the new attempt was dead.

rolli

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Thank you for the information Rolli. You seem to know quite a bit about the rep PAM cases. Are the rep PAM automatics always thicker (taller) than the genuine ones? Or do they make up for the height of the case, needed for Asian 7750, by cutting down on the height of the bezel? I've also noticed that on the DSN autos his case back protrudes below the bottom of the case more than other reps.

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with the cartel ultimate automatic pams there is no problem to swap a swiss 7750.

the asia 7750 have the same measurements like the gen 7750.

the inner mesuremets of the cases are perfect for the swiss 7750.

my watchmaker did it with the 229 firenze. perfect result.

submersible pams like the 24 is also to use for this swap.

also here my watchmaker did it with my 024A submersible.

and with the 253 he did this modification, perfect result.

davidsen auto pams.

davidsen uses the old asia 7750b1 movement for his standard automatic pams like 104, 164, 240, 165, 091.

this old asia movement is taller in the measurement and has the ugly distance ring on top,

no swap possibility and sunken date wheel.

otherwise you would use the longer asia gears, but this is not to recommend. you don't have the presise swiss technology effect.

only the new power reserve models 027,028 have a gen swiss movement inside.

rolli

Thank you for the information Rolli. You seem to know quite a bit about the rep PAM cases. Are the rep PAM automatics always thicker (taller) than the genuine ones? Or do they make up for the height of the case, needed for Asian 7750, by cutting down on the height of the bezel? I've also noticed that on the DSN autos his case back protrudes below the bottom of the case more than other reps.

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Wonder why they have just never copied the ETA 775X movements instead of modifying the hell out of the 7750. They share the same base ebauche, are the same size and are interchangeable with one another. Just sounds like they have engineered everything backwards. Think how much work from their end had to go into turning a 7750 into a 7753. Granted some functions like quick date change on the 7753 are not interchangeable, most of the other parts are. Now the work they have done regarding moving seconds to 6 or 12, is understandable as they have the same limitations as every other Swiss manufacture regarding costs associated with R&D.

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i think the cartel watch maker did copy the valjoux 7751, this one with moonphase etc etc.

rolli

Wonder why they have just never copied the ETA 775X movements instead of modifying the hell out of the 7750. They share the same base ebauche, are the same size and are interchangeable with one another. Just sounds like they have engineered everything backwards. Think how much work from their end had to go into turning a 7750 into a 7753. Granted some functions like quick date change on the 7753 are not interchangeable, most of the other parts are. Now the work they have done regarding moving seconds to 6 or 12, is understandable as they have the same limitations as every other Swiss manufacture regarding costs associated with R&D.

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I thought they did with the 7751, you just don't see this movement in to many watches. Other then a Breitling Datora and a few other smalle brands, I do not know what other Gen. peice uses it. I know Panerai has not used it.

i think the cartel watch maker did copy the valjoux 7751, this one with moonphase etc etc.

rolli

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