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Eta 7750 Chrono Issue


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hi guys,

I can not get the Chrono of the ETA 7750 to the correct re-set position and in the set position the driving pinion does not drive the chro wheel. I have attached a couple of pics to see if anyone can see what I have done wrong. When I push the pushers the cam does not rotate as it should I am a bit lost to say the least. Or has anyone got some basic tests I could do the find the fault.

 

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BRIDGE REMOVED

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Edited by clockboy
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Cb its very dificult to explain but i will tryfirst i think your cam is not seated properly low enoygh.

Second its not positioned as it should from the start see swisslab eta how it should be put on place oriented

Also your bridge which holds the reversing wheel(lower bridge) might not be seated as it should, push the reset pusher before tightening the bridge down wjth the 2 screws

Regarding the 60 seconds pinion not driving the chrono seconds wheel there could be many posibilities also,the spring which pushes the clutch not put as it should be, or maybe the pinion itself not put in the lower jewel or in the clutch bushing and many more reasons

br

emso

p.s: sent from my s****y phone so sorry for typing mistakes

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Thanks Emso, I have stripped the chrono and will have another go tomorrow using the swisslab ETA assembly. I must say when I stripped I did not find anything obviously wrong which is a bit worrying. I did notice it was in the wrong start position & the driving pinion that drives the Chrono wheel was not touching the wheel and this might be because i moved the adjusting screw by mistake when fiddling trying to get it to work. 

Edited by clockboy
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Well i believed you did not touch the eccentric, but if you did then that could be a reason also see the technical documents or the swisslab and you will see how they should mesh,too much and the movement will stop, less than needed also stoppage or not working properly chrono

br

emso

p.s: sent from my s****y phone so sorry for typing mistakes

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Thanks Emso,  Cleaned all chrono parts again this morning & inspected closely with a 10x loupe & found that the Oscillating pinion bottom pivot broken which explains why the Chro wheel was not being engaged. Why the rest of the Chrono was not working might be because it was just in the wrong position to start with. When new part arrives I will assemble using the ETA assemble chart.

As a matter of interest there is one part that is not the same on the ETA chart or on Marks vid any ideas see pics.

It is the hour counting wheel & sorry about poor pics

 

TOP VIEW

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SIDE VIEW

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BOTTOM VIEW

post-234-0-97460500-1426927375_thumb.jpg

Edited by clockboy
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Yes it is the hour counting wheel, it goes above the mainplate,not on this side of the movement

Regarding the osilatin pinion it gets broken when itis not seated properlyand you screw the plate over withput aligning other pivots

br

emso

p.s: sent from my s****y phone so sorry for typing mistakes

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