# Regulating a Powermatic 80 Movement (ETA C07.111)



## Thethirdrowe (Feb 16, 2015)

I've got a Tissot PRC 200 Automatic with the Powermatic 80 movement. I always enjoy tinkering with my stuff, and watches are no different. Regulating movements is generally one of the easiest ways of messing with a watch (to me), and I would like to do this to my PRC. It is running slightly slow right now (well within spec), and I prefer fast watches.

BUT, the C07.111 movement has no regulator bar or screw. What it does have, is two screws located on the balance wheel





Does anyone have experience with this movement? I don't want to mess the watch up, as it's running fine, but I always enjoy making things run "more fine".


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## dom_ (Jan 29, 2012)

Have not worked on one and not got a repair manual for one. 

But.... I assume you rotate the screws on the balance arm for fine adjustment and move them along the groove for more course adjustment. 

Imagine spinning on an office chair, hold your arms out and you slow down, pull your arms in and you speed up.


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## Thethirdrowe (Feb 16, 2015)

Those were my thoughts exactly. 

I assume I would need to move both screws the exact same amount to keep the wheel balanced in the Z-axis, right? I foresee it potentially creating undue friction on the balance wheel jewel.


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## emso (Jan 14, 2008)

yes you're right you need to turn the screws
you can adjust it +-30 sec/day maximum
screws flat end pointing to the center of balance wheel -30s/d
screws flat end outwards +30 s/d

yes you need to move both screws the same amount, dont forget to support the balance wheel to avoid damaging the balance pivots

br
emso


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## Thethirdrowe (Feb 16, 2015)

I gave each screw about 1/10 of a turn, and will time it with Twixt. Thanks for the info!


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## Thethirdrowe (Feb 16, 2015)

1/10 turn was waaaay too much. The winner was to turn it barely past the notch the screw resides in. It's averaging +1.2/day now, which might as well be perfect in my book.


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## CristobalGordo (Jun 28, 2014)

I'm not seeing how you would adjust these screws. Do you need to completely remove the balance wheel? And do this every time you need to make an adjustment? Can you adjust these screws while the balance wheel is in place by being very very careful not to press down?

Are these movements supposed to not need regulating ever? Or maybe when you send it in for servicing they just throw the old movement in the trash and give you a new one.

I like the 80 hour power reserve and the anti-magnetic properties but this doesn't seem like it was designed to last a lifetime.


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## Thethirdrowe (Feb 16, 2015)

I left the balance wheel in. Pull the crown out so the wheel isn't moving, and lightly mark one of the screws with a sharpie so you know which screw has been moved. You'll have to manipulate the crown in and out in order to rotate the balance wheel to a new screw. The idea is, the flat part of the screw weighs less, so the rotational inertia lessens if the flat bits are to the outside. 

They say the movement doesn't need adjustment, and they are correct if you're fine with the accuracy it comes with. Mine came out of the box within COSC spec, but I wanted to make it better.


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## xzqt (Jan 26, 2013)

I don't have experience with this movement, but in view of the regulator mounted on the balance wheel.
May be better to derive a method of supporting the balance wheel before adjustment, afraid the chances of breaking the pivot is there.


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## nello (Jan 2, 2014)

Anyone else regulate one of these movements?
Any other issues or thoughts?


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## 4236 (May 28, 2010)

Can you please check throught your loupe, how is the balance wheel and pallet fork made. Are they made in the traditional materials with pallet stones, or some kind of plastic?


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## cooma (Mar 14, 2014)

Thethirdrowe said:


> I left the balance wheel in. Pull the crown out so the wheel isn't moving, and lightly mark one of the screws with a sharpie so you know which screw has been moved. You'll have to manipulate the crown in and out in order to rotate the balance wheel to a new screw.


Did you hold the wheel somehow while screwing? I suppose the shock absorbing mechanism protects pivots, so they doesn't broke immediately when touching but still you can't use force to rotate a screw. By the way the screws uses similar idea than for example adjusting weights in balance wheels of Patek Philippe movements.


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