Need help with an inherited Longines (quartz conversion)

[MtV]

Hey folks,
this might be my first post in the Longines sub-forum, hoping you can help me with some expertise.



Here’s the story:

My best mate has inherited his granddad’s Longines. It’s from the 70s, a solid gold piece, albeit not exactly one of the sought-after styles of today. His granddad spent the last 2 years of his life in bed, but he still loved the watch, so they had the automatic converted to a Quartz movement as he wasn’t moving enough to keep the automatic going.
Unfortunately, the original movement is nowhere to be found, but my friend would love to get it back to the original spec. On a bill from an earlier service, here’s what we have regarding info:



I’ve googled “Longines 4641” but the results show all kinds of pieces. I haven’t opened it yet, can do that if 4641 isn’t actually the reference I need.
The caliber is noted as “633”, of which I can find spare ones on eBay. However, they’re marked “633/1”, “633/2” etc.

Could anyone shed some light on what those “/1” etc mean, what we need to look for, or possibly recommend a way of finding the answer? Happy to put in the legwork, but knowing the depth of knowledge here it felt like a good place to ask.

Thanks a lot!

 

[rendo]

I think this is a reference 46411, not 4641. If that’s correct, it had caliber 633.1 (ETA 2824) before the swap. Here is one with a black dial that was offered on eBay:
https://www.ebay.com/itm/354527407521

 

[MtV]

Thank you, having the right ref is extremely helpful. The watch will go to my watchmaker next week, I hope the didn’t do too much damage when swapping the movement. If all is fine I’ll then look for a 633.1.

 

[gatorcpa]

There are several of these movements for sale on eBay. Prices seem to be in the low $200 range, but these will likely need a service to work properly along with installation costs.

So this will not be a cheap project.
gatorcpa

 

[MtV]

gatorcpa

There are several of these movements for sale on eBay. Prices seem to be in the low $200 range, but these will likely need a service to work properly along with installation costs.

So this will not be a cheap project.
gatorcpa

He‘s aware, but financial thoughts don’t really play a role here. His granddad played a huge part in his life and he just wants to get the watch back to former glory. Thanks though!