in order to buy appropriate spares in my attempt to service an Omega 175.0083 (7750) I need some advice:
I've already been suggested to replace MS:
Barrel is Ok and I'm thinking of buying a new MS and moebius 8217 for barrel lubricating as I don't want to spend money on recommended Kluber 125 grease.
Should I consider instead buying a barrel complete (assuming Barrel complete (180.1) comes with MS installed) wich supposedly comes prelubricated ?
Attached image shows automatic device bridge with evident sign of wear from where, to my understanding, the problem orginated: a screw came off
I cant find original part.
ETA part is different from Omega in that the Omega is larger and partially covers hammer two function and the chronograph cam.
Beside that and since the watch has no crystal back case I think those parts are perfectly interchangeable.
Do I need to replace the bridge or are there alternative aproaches to this problem?
I am servicing my first 7750 (thank you Mark for the YT videos and Lawson for the Disassembly/Assembly walk-through).
The movement is not new - let's say it has an obscure unknown history It appears to be a genuine swiss 7750, but with a lower grade finish (very low...)
When putting back the balance stones I noticed that there were two sizes (two pairs, because the cap stones fit the hole jewel settings). I put the smaller stone and hole-jewel on the mainplate and the larger ones on the balance cock. I tried to but the larger setting on the mainplate but it didn't fit quite right. I believe the springs are the same size - its just the stones that differ a bit (aprox 0.1mm)
So my question is: did any of you stumbled upon the same issue? Is it normal for a 7750 to have two different stone sizes?
Hey, guys, I have a 7750 movement where the rotor screw snapped off. I opened it up and it appears the rest of the screw is still inside the rotor post. Is there anything I can do to screw it back out?
That's good shout. I suspect they may have had multiple sources for the balance, and thus the shim was fitted in some cases, to allow them to compensate for the 0.1mm or so difference between shaft lengths.
The shim can be source of problems though as it can act as a pivot point if it is not fitted in entirely the right spot, and this could introduce errors in the balance alignment, and it does introduce the possibility of either forgetting to re-fit it, and screwing the balance down hard on to the jewels, thus damaging the pivot(s) and/or the jewel(s), or fitting it when not needed if a different "compatible" replacement balance is fitted which has a shorter shaft, and then getting in to head scratching mode when the thing rattles around like a pea in a biscuit barrel.
Thanks for the answers. A more detailed description first:
I reassembled, oiled the pallets with 941 and let the watch run for 48 hours dial up.
Then I did the poising and after a full wind the first measurement on the timegrapher with result +2/0/+2.
Then I wore the watch (normal day in the company) for 24 h. Then after a full wind second measurement with result +9/+7/+9.
So maybe the mistake was to let the watch run static in dial up position instead of "shaking" it while wearing? Or the period of 48 hours was too short? Right now the watch is on my wrist and I am observing the "real" gain compared to the atomic clock.