# Omega Seamaster 300M ETA 255.563



## vizi

Custom-made thermocompensated Omega Seamaster 300M

I bought a Bond-style Omega Seamaster 300M with Cal.1538 (ETA 255.461). I replaced the electronic module on the movement with the electronic module from the ETA 255.563 (used in the latest issues of the original Longines VHP - non-perpetual calendar - as caliber L.237.2) and as a result I ended up with an ETA 255.563 thermocompensated movement in my new Seamaster. 'Special edition' and unique as it was the first thermocompensated movement from ETA that used a single oscillator design with built-in thermistor on the IC replacing the dual-oscillator design. Performance (accuracy-wise) is identical to the dual-oscillator ETA movements as well as the current ETA Thermolines as these movements also use the 
"inhibition" scheme for thermocompensation.


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## ppaulusz

vizi said:


> ...I bought a Bond-style Omega Seamaster 300M with Cal.1538 (ETA 255.461). I replaced the electronic module on the movement with the electronic module from the ETA 255.563 (used in the latest issues of the original Longines VHP - non-perpetual calendar - as caliber L.237.2) and as a result I ended up with an ETA 255.563 thermocompensated movement in my new Seamaster...


That's the way Omega should have manufactured the Seamaster in the factory!:-!


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## PedroJ

Congrats Vizi for the wise upgrade performed.:-!
I'm also interested in such "chimere" watches and wonder how you did the "grafting". You did it yourself? A watchmaker? An AD eventually?
Thanks for sharing your experience with us!
Pedro


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## vizi

I say thank you for it kind topic my companions.:thanks


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## M4tt

I cannot begin to explain how impressed I am with this surgery - where did you source the module?


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## vizi

M4tt said:


> I cannot begin to explain how impressed I am with this surgery - where did you source the module?


Friend Longines works a trademark into a service, on Budapest


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## vizi

PedroJ said:


> Congrats Vizi for the wise upgrade performed.:-!
> I'm also interested in such "chimere" watches and wonder how you did the "grafting". You did it yourself? A watchmaker? An AD eventually?
> Thanks for sharing your experience with us!
> Pedro


It was my idea to replace the original movement (the electronic module of the movement). A friend of mine is a watchmaker so he carried out the procedure.

I made the exchange at this;https://www.watchuseek.com/showthread.php?t=92227


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## jon12w

Cool. How different is this to a cal 1441?


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## ppaulusz

jon12w said:


> Cool. How different is this to a cal 1441?


"_...I ended up with an ETA 255.563 thermocompensated movement ...it was the first thermocompensated movement from ETA that used a single oscillator design with built-in thermistor on the IC replacing the dual-oscillator design._ _Performance (accuracy-wise) is identical to the dual-oscillator ETA movements as well as the current ETA Thermolines as these movements also use the "inhibition" scheme for thermocompensation._"
The ETA 255.561 (Omega Cal.1441) has dual-oscillator.


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## vizi

ppaulusz said:


> "_...I ended up with an ETA 255.563 thermocompensated movement ...it was the first thermocompensated movement from ETA that used a single oscillator design with built-in thermistor on the IC replacing the dual-oscillator design._ _Performance (accuracy-wise) is identical to the dual-oscillator ETA movements as well as the current ETA Thermolines as these movements also use the "inhibition" scheme for thermocompensation._"
> The ETA 255.561 (Omega Cal.1441) has dual-oscillator.


George,in this manner true:-!


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## Bruce Reding

A most excellent project! :-!


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## bullosa

Yes, very inspiring.


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## vizi

Bruce Reding said:


> A most excellent project! :-!


Thanks Bruce


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## jon12w

ppaulusz said:


> "_...I ended up with an ETA 255.563 thermocompensated movement ...it was the first thermocompensated movement from ETA that used a single oscillator design with built-in thermistor on the IC replacing the dual-oscillator design._ _Performance (accuracy-wise) is identical to the dual-oscillator ETA movements as well as the current ETA Thermolines as these movements also use the "inhibition" scheme for thermocompensation._"
> The ETA 255.561 (Omega Cal.1441) has dual-oscillator.


Ooops, that will teach me not to skim read.... Ive just bought some 255.561s with a view to mounting them instead of the 1438/1538s I have. Do you know how hard swapping the electrics is on these? I know some movts like the f300 are split really easily - electrics on one plate and mechanicals on the other. Are these the same?


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## ppaulusz

jon12w said:


> ...Ive just bought some 255.561s with a view to mounting them instead of the 1438/1538s I have. Do you know how hard swapping the electrics is on these?...


All I know that fellow forumer, Vizi, managed to do it himself.


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## Seamaster73

Excellent, and interesting work.

Although I have to say, my standard Bond Seamaster quartz was quite astonishingly accurate, rarely being off by more than a few seconds between GMT/BST changes.


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## RPF

Omegines! 

Lomega! 

Franken ETA quartz! 

Horrors!!!

Resuming normal transmission... "Salut" sir, for a very interesting customization.


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## vizi

RPF said:


> Omegines!
> 
> Lomega!
> 
> Franken ETA quartz!
> 
> Horrors!!!
> 
> Resuming normal transmission... "Salut" sir, for a very interesting customization.


Likes the pun,:-!I say thank you for it!


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## vizi

Seamaster73 said:


> Excellent, and interesting work.
> 
> Although I have to say, my standard Bond Seamaster quartz was quite astonishingly accurate, rarely being off by more than a few seconds between GMT/BST changes.


Says thanks to you ,1538 original movemnts accurate but not thermocompensated movement.


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## Eeeb

ppaulusz said:


> All I know that fellow forumer, Vizi, managed to do it himself.


I am suprised this worked. I was under the impression the thermistor was mounted on an additional module which then attached to the control module.

Hummmm.... I have all the docs somewhere... The doc giving the parts explosions are the relevant ones... It will be a week or so before I'll have time to dig up everything.

Priorities... always Priorities :roll:


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## ppaulusz

Eeeb said:


> I am suprised this worked. I was under the impression the thermistor was mounted on an additional module which then attached to the control module...


Jim, the thermister is built-in on the IC. In other words the thermister is not on an additional module but rather it's an integrated part of the electronic module of the thermocompensated movement.


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## vizi

ppaulusz said:


> Jim, the thermister is built-in on the IC. In other words the thermister is not on an additional module but rather it's an integrated part of the electronic module of the thermocompensated movement.


Thanks for the answer George, i agree.


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## webvan

ppaulusz said:


> "_...I ended up with an ETA 255.563 thermocompensated movement ...it was the first thermocompensated movement from ETA that used a single oscillator design with built-in thermistor on the IC replacing the dual-oscillator design._ _Performance (accuracy-wise) is identical to the dual-oscillator ETA movements as well as the current ETA Thermolines as these movements also use the "inhibition" scheme for thermocompensation._"
> The ETA 255.561 (Omega Cal.1441) has dual-oscillator.


I just picked up a used Seamaster 200 with the Omega 1441 and after taking a close look at the ETA number it turns out to be an ETA 255.563, wonder what's up with that! Will take pictures tomorrow if that hasn't been done before. BTW the watch lost 1s/week so I'm going to try to adjust it about 13 impulses if I'm counting right...


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## ppaulusz

webvan said:


> I just picked up a used Seamaster 200 with the Omega 1441 and after taking a close look at the ETA number it turns out to be an ETA 255.563, wonder what's up with that!...


The original movement (ETA 255.561) got replaced (during service) with the ETA 255.563. Both are thermocompensated and have identical accuracy specifications.


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## webvan

That makes sense, thanks, I'm a tad disappointed not to have the original movement with a dual-oscillator (it was really hard to tell from the pictures, see below) I wonder if I can send it back to the seller to get the real deal...Still, it's better to have a working one than a damaged one ;-)

1441 with 255.561 (from the review)










1441 with 255.563 :


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## ppaulusz

webvan said:


> ...I'm a tad disappointed not to have the original movement with a dual-oscillator...


Strange as it may seem but yours has dual-oscillator...:think:
We know that the ETA 255.563 has a single oscillator with integrated termister in the IC.
We also know that ETA released the ETA 255.563 (as replacement for the ETA 255.561) in the early 1990s.
Furthermore we know that the thermocompensated Omega Seamaster Professional 200M was manufactured for a very limited time: 1988-1989.
My conclusion is that your Seamaster must have had something wrong with its original movement as its mechanical module was replaced. However the old (original) electronic module got fitted onto the new mechanical module. That's how I would explain the mismatched mechanical and electronic modules.
These modules are interchangable so you should not worry about the performance of the movement. 
It's a bit strange but not unexplainable.
Enjoy your watch, it uses a thermocompensation technology that was not bettered since!|>


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## stanislav

the bracelet of this Seamaster is the same type as that of Longines Conquest Perpetual VHP 200 m, the clasp is different, all links look solid


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## webvan

@ppaulusz - thanks for this explanation, makes me feel like I have a unique watch now ;-) Will now see how my 13 impulses have helped with accuracy in a week's time.

From your VHP article, the "normal" 255.563 is indeed very different :


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## vizi

vizi said:


> Custom-made thermocompensated Omega Seamaster 300M
> 
> I bought a Bond-style Omega Seamaster 300M with Cal.1538 (ETA 255.461). I replaced the electronic module on the movement with the electronic module from the ETA 255.563 (used in the latest issues of the original Longines VHP - non-perpetual calendar - as caliber L.237.2) and as a result I ended up with an ETA 255.563 thermocompensated movement in my new Seamaster. 'Special edition' and unique as it was the first thermocompensated movement from ETA that used a single oscillator design with built-in thermistor on the IC replacing the dual-oscillator design. Performance (accuracy-wise) is identical to the dual-oscillator ETA movements as well as the current ETA Thermolines as these movements also use the
> "inhibition" scheme for thermocompensation.


Hi everyone,

Just an accuracy update of my Omega Seamaster Professional 300M (with the modified thermocompensated movement):
Exactly 12 months ago I calibrated the watch (by myself) and set it to the atomic time-signal. Now it is 3 seconds ahead of the atomic time-reference, in other words it has gained only 3 seconds in one year!:-!


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## Gene K

vizi said:


> Hi everyone,
> 
> Just an accuracy update of my Omega Seamaster Professional 300M (with the modified thermocompensated movement):
> Exactly 12 months ago I calibrated the watch (by myself) and set it to the atomic time-signal. Now it is 3 seconds ahead of the atomic time-reference, in other words it has gained only 3 seconds in one year!:-!


Dont reset it! Do a long term test to see how it does for the life of the battery. Just check it once a month.


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## Eeeb

Gene K said:


> Dont reset it! Do a long term test to see how it does for the life of the battery. Just check it once a month.


Yes... it would be interesting to see if there is any effect. Data!! :-!


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## South Pender

vizi said:


> Hi everyone,
> 
> Just an accuracy update of my Omega Seamaster Professional 300M (with the modified thermocompensated movement):
> Exactly 12 months ago I calibrated the watch (by myself) and set it to the atomic time-signal. Now it is 3 seconds ahead of the atomic time-reference, in other words it has gained only 3 seconds in one year!:-!


That's wonderful! Can you tell us how much you wore it during the 12-month period? Every day, all day? Half the time, all day? etc. And if it was off your wrist for extended periods, at what temperature was it stored?


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## vizi

South Pender said:


> That's wonderful! Can you tell us how much you wore it during the 12-month period? Every day, all day? Half the time, all day? etc. And if it was off your wrist for extended periods, at what temperature was it stored?


Summer and winter, I wore all day (the night) I live in continental climate, this corresponds to the temperature. The tests continue to battery end.


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## vizi

Omega Seamaster 300M with Cal.1538 (ETA 255.461).electronic module from the ETA 255.563 - YouTube


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## webvan

Nice video, how has its accuracy been?


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## webvan

Good accuracy then?

Since you posted tour video I've been thinking about this again and I'm half tempted to pick up an SM300 and putting a TC module. Not quite clear whether a 1441 module would work or only a 1445/Longines 237.2. Based on what's been discussed here it seems either would work 

@jonw - did you ever give it a shot?


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## vizi

webvan,
Yes,good accuracy! 1441(ETA 255.561),1445,(ETA 255 472) . module would works, 
SM300 1538 basic caliber = ETA 255.461 /561


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## webvan

Thanks, would need to sacrifice a 1441/1445 then. Did your watchmaker give you any details on what had to be done to make it work? It seems you had it done twice maybe? Once for a 1438 and then the 1538? And did it once yourself?


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## vizi

-"Thanks for 1441/1445 will be casualties." (looking around the net, is located), You just have to put the module and it works fine.

You do not need special knowledge to solve the problem watchmaker .


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## webvan

Haven't forgotten about this project and having recently found a Longines L174.2...










...in a damaged VHP that can be sacrificed it seems I've never been closer to giving it a shot with an SMP 300...still not sure how difficult the project is, you didn't take pictures did you?

It seems you first did it yourself for the 1438 but had a watchmaker do it for the 1538 ? Is it because it was difficult the first time or because you didn't want to take any risks with an expensive SMP300 ? I guess I could start by trying to pull apart the L174.2 to see if I can handle it myself...


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## vizi

1438 is not difficult to convert, so the move came out in 1538 so did my friend the watchmaker in his hand movement ... and if ...had done it.
If you have a little practice you can go to the conversion


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## webvan

Thanks for the answer but I'm afraid I don't really understand what you mean exactly ? Your watchmaker did the conversion because he had both movements available so it was more convenient ?


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## PeterG_SVK

If the movements are the same size (compatible), I think the only problem is to remove the hands to replace the dial and put them back. Maybe also removing the dial, but you can learn that on the Longines movement. Everything else you can done yourself - recently I "restored" my old Certinas...


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## harris498

Can't wait to see how this turns out!


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## webvan

PeterG_SVK said:


> If the movements are the same size (compatible), I think the only problem is to remove the hands to replace the dial and put them back. Maybe also removing the dial, but you can learn that on the Longines movement. Everything else you can done yourself - recently I "restored" my old Certinas...


Actually I don't think anything needs to happen on the dial side, my understanding is that only the electronic module needs to be separated from the mechanical module on both movements so they can be switched.

I'm not sure how that's done though, is it just a matter of removing some screws or is there more to it? That's the info I was hoping to get from vizi before I make some damage!


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## PeterG_SVK

Hmmm ... in my watch the ETA movement is held in the position only by outer plastic ring fixed by crown stem, once the crown stem is pulled out, the movement with dial and hands can be removed out. If you want to swap/replace the movement, you have to remove original hands and dial, the same on the replacement movement, swap the movements, put back the original dial and hands. Maybe I missed something what you would like to do?


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## webvan

What Vizi did on both a 1438 and a 1538 is switch the original non-TC electronic module for the TC electronic module of a compatible movement to get "aftermarket" HAQ performance.


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## Eeeb

That should work. Indeed, ETA recommends this as the process for upgrading the 205.111 to the 205.911. Swapping electronic modules is relatively simple for anyone who can get into movements. Of course, this swapping can not be universally done. But many TC movements have non-TC counterparts that vary only in the electronic module.

However, Swatch Service often requires the old module to be returned before they will issue another. So you may have to source the module yourself...


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## vizi

Removing some the screws (4) ,electronic module needs to be separated from the mechanical module on both movements so they can be switched. ,done !


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## webvan

ok, they're just "pressed" together ? I see 3 screws below but there might be one under the "wings" of the digital calibration terminal.

@Eeeb - Right, and I finally found a cheap donor (the second VHP I got last week), now I'd need to get the Seamaster 300, a more expensive problem...

Looking a picture of the movement :










it seems like the electronic module is held by three screws, one between the battery and the crown and two on both sides of the "plaque", hopefully removing them would allow for the circuit to come out nicely...

...but the 255.511 technical doc posted by Vizi a while back in another thread doesn't show have the two modules fit into one another.


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## Eeeb

ETA had a separate add on board for TC is some of their early models. It is now integrated into the main board. The eta.ch service portal should be able to provide sufficient documentation to show what is what and how to do it for the specific models.


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## PeterG_SVK

Eeeb said:


> ... Swapping electronic modules is relatively simple for anyone who can get into movements. Of course, this swapping can not be universally done. But many TC movements have non-TC counterparts that vary only in the electronic module.
> ...


OK, it's clear now. However, isn't easier to swap whole movement, particularly if the electronic modules are not compatible?


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## vizi

In the picture you can see the four screw






....two more = 6 screw


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## Eeeb

PeterG_SVK said:


> OK, it's clear now. However, isn't easier to swap whole movement, particularly if the electronic modules are not compatible?


Yes, it is easier to just swap the movement. However, movements cost more than modules.


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## PeterG_SVK

Can you buy TC electronic module separately??? Or whole TC movement? Where? I've thought about movements from old VHP watches...


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## vizi

Yes-can you buy TC electronic module separately,the nets comes to look for TC electronic modules.


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## webvan

The only way of buying them that I'm aware of is finding a cheap donor watch or a replacement movement...took me a while, but I got lucky for both, VHP donor and 1680 for the movement.


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## Hans Moleman

webvan said:


> The only way of buying them that I'm aware of is finding a cheap donor watch or a replacement movement...took me a while, but I got lucky for both, VHP donor and 1680 for the movement.


These guys advertise with ETA parts.


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## Hans Moleman

Hans Moleman said:


> These guys advertise with ETA parts.


€25 for a 252.611 electronic module.

Two problems with that:
- They are wholesalers. 
- ETA hasn't got them right now.


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## Catalin

Hans Moleman said:


> €25 for a 252.611 electronic module.
> 
> Two problems with that:
> - They are wholesalers.
> - ETA hasn't got them right now.


I definitely want one of those as a backup for my VHP Perpetual - how do we get some of those?


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## jdbaldoc

I have a 20 year old Omega Seamaster Gold & Stainless with a 1438 caliber module and movement. It runs about +12 seconds per month. I would like to see if I can convert it to a TC module. I think I read it was a ETA255.563.

Where can the ETA 255.563 or compatible module be bought to do what I am contemplating on doing?

Is it a simple (4) screw removal of old module and replace with the TC module ETA255.563?

After replacement how hard is it to adjust, and do you need any special equipment to adjust the +/- seconds?

I read on here another person did it but there was no follow up. I believe he got his module from and older damaged Longines.

I would appreciate any help or links on answers to my questions above?

Thanks,

John Baldock
Reno, NV.[/QUOTE][/QUOTE]


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## Eeeb

jdbaldoc said:


> I have a 20 year old Omega Seamaster Gold & Stainless with a 1438 caliber module and movement. It runs about +12 seconds per month. I would like to see if I can convert it to a TC module. I think I read it was a ETA255.563.
> 
> Where can the ETA 255.563 or compatible module be bought to do what I am contemplating on doing?
> 
> *A *Is it a simple (4) screw removal of old module and replace with the TC module ETA255.563?
> 
> *B *After replacement how hard is it to adjust, and do you need any special equipment to adjust the +/- seconds?
> 
> I read on here another person did it but there was no follow up. I believe he got his module from and older damaged Longines.
> 
> I would appreciate any help or links on answers to my questions above?
> 
> Thanks,
> 
> John Baldock
> Reno, NV.


*A *Swatch service will only sell them on a 'replacement' basis. Your authorized watchmaker has to send in the old one before they will send a new one. eBay sometimes has them. One sold two weeks ago. Donor watches are available. The two modules (TC and non-TC) are drop in replacements for each other.

*B *After you drop in the replacement you need to regulate the 'new' movement to attain maximum accuracy. For this you need to know its error and them perform the regulation. The process of regulating is well documented in other posts. The forum search will find them for you.

Good luck!!


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## webvan

Yes I did it too and now my SMP300 is my most accurate watch, around +2 spy at room temp!

Not all VHP electronic modules are compatible though, some use the 1441 with the external thermistor (and dual "flaps") and that one won't work as there is no space for the thermistor, the one you want is shown on the first page here.

Rereading your message I see you have the SMP200 with the 1438, not the SMP300 with the 1538, so actually you probably need the module with the external thermistor. What you could do is remove the module and post a picture here so we can find out for sure.


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## jdbaldoc

I have an Omega Seamster Professional 300m Gold & Stainless watch with the 1438 caliber movement. 

I just bought a new in the box 1441 module with the dual oscillator module board.

Questions:
1. Can I just replace the 1438 electronic module with the 1441 electronic module?
2. What screws do I remove to take both modules off for replacement? Any pics would be helpful?
3. What battery should be used for the new 1441 electronic module?
3. Is there an instruction manual on how to regulate the dual oscillator 1441 module?

I want to try to do this myself so any information from you guys who have already done this would be greatly appreciated.


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## vizi

If you read through the topic(Omega Seamaster 300M ETA 255.563) , you will find all answers.


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## 11GTCS

I hate to revive this thread after so long, but I just picked up a watch with a similar movement, and I was curious if swapping to the HAQ module results in the watch no longer having jumping hour. I'd love to make this swap, but it wouldn't be worth it to me if I lost that feature, it's far to convenient when traveling. @vizi, any insight?


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## ferrarif1fan

I made the same swap on a 2264.50. All you are swapping is the brains of the watch. All of the mechanical functions of the watch are exactly the same. The only difference is that it is much, much more accurate.


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## 11GTCS

ferrarif1fan said:


> I made the same swap on a 2264.50. All you are swapping is the brains of the watch. All of the mechanical functions of the watch are exactly the same. The only difference is that it is much, much more accurate.


Perfect, thanks! yeah I just wasn't sure if the jumping hour feature was controlled by the brains or the motion-works, since I'm relatively new to the area of HAQ and quartz in generally, having mostly collected mechanical for the past few years.


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