A7750 2nd wheel and/or balance wheel assembly needed - Problem?!

[hackR]

I'm working on one of my older tri-compax 7750 (3-6-9) which i believe to be low-beat, but can't recall...i broke the end of the pivot on the 2nd wheel so i needed a replacement...i have a carcass of an older 7750, so i grabbed the 2nd wheel...only to find out that the shaft/pivot of the 2nd wheel is not a uniform diameter - it starts out smaller and then goes into a slightly larger shoulder at the wheel hub...it's stepped, if that makes sense...well, i then discover that the gen eta 7750 2nd wheel is also stepped...the tri-compax has a 2nd wheel that is a single/non-stepped diameter...see the pix above...

what's creating my problem is that the jewel in my tri-compax has a smaller diameter hole than the hole on the carcass 7750 or the eta 7750 jewel - which is larger...i am debating trying to pop out the jewels and swap them, but i don't have the right tools to remove/replace the jewels...not sure if pressing them out will make them break or not, too...

i've tried using the carcass plates - but ran into a snag...i only have the tri-compax balance wheel assembly which has male studs to mount into the female holes in the plate...i don't have a spare balance wheel assembly with female holes in the assembly to match up to the male studs on the plate...i have no skills to be able to break down the balance wheel assembly to attempt a swap to accomodate the stud connection difference...

Here's a pix of the balance wheel assembly i need - see the holes in the arm?

so - my options are:

1) finding a uniform thin shafted 2nd wheel for an a7750; w/o the stepped shaft

2) swapping jewels

3) finding a balance wheel assembly with holes to fit the studs in the plate

i cannot change the plates around as they are different...especially with how the balance wheel assembly connects to the plate...

any help advice and/or parts is appreciated...

the 2nd wheel is: ETA Valjoux movement 7750 part number 224 (second wheel,long lower pivot); also, sometimes refered to as a 4th wheel?!

R-

[Rolexman]

Pop the jewel out with a plastic pen tip. You can push it right out. Getting one back in is a greater challenge as it needs to be seated straight. I've done it before. Before I bought a staking set so you can do it too! Just lay the bridge down flat. Position the jewel and push it in with a straight plastic tip. Push from the underside (flat side). Just do it gently, like making love to a woman

You got nothing to loose my friend

[hackR]

great...was hoping it might be easy to work the jewels - easier than finding Asian parts...

Is there a side I should push the newly from?...dial side to back or vice-versa?

as always...thx!

[Rolexman]

great...was hoping it might be easy to work the jewels - easier than finding Asian parts...

Is there a side I should push the newly from?...dial side to back or vice-versa?

as always...thx!

Dial side or back side depends on the bridge you are working on. You always push a jewel out from the cup side of the jewel and you push it in from the flat side. If you look at the jewel from both sides you know what I mean

Good luck and let us know how it went.

Mark

[hackR]

Thx, Mark...gotcha...will try and let you know...R

[krpster]

Oooh. Sounds interesting. Looking forward to hearing how you make out hackR.