*Aero* Posted October 5, 2012 Report Share Posted October 5, 2012 My recently bought Grand Carrera 36RS had stopped working after a couple of months - so after asking around for anyone close to my location, being able to repair it I decided that for the costs involved in shipping and repair I might as well get a new one or have a go and try to repair it myself So that's what I did - following as much as possible to an online manual for the 7750, and using basic tools I managed to get it all apart! So far the only broken things I found are the oscillating pinion, which had the lower pin missing, and the escape wheel ( I broke its top pin while assembling it after cleaning ) I don't really know the real cause of it stopping working so maybe someone can shed some light on this. What I've noticed during disassembly is as follows: Before I removed anything, the balance wheel was not moving. When took off the auto bridge I found the oscillating pinion.60s. damaged. Continued the disassembly with no problems till I got to the balance bridge, it was still stationary - took that off as well Then it was the pallet bridge turn - as soon as I took it off the mainspring unwound with all the gearing spinning like a turbine! Removed all the remaining stuff with out any problems - I noticed a good amount of oil on the main plate - maybe it was too much oil? I re-assembled the mainspring, its related gears, the escape wheel, pallet fork and bridge and the balance bridge assy, nudged the balance wheel and it started ticking again - wound the mainspring a couple of clicks and it kept on ticking away. At this point I think that what ever problem there was. it is now gone...or at least that's what I want to believe! Now I only have to wait for the parts I ordered off ebay to continue. Hope that gen parts fit on the asian 7750! As for oiling the mechanism I'll have to do without the proper oils - they're too expensive at about 30Euros for each type, and there are about 5 types of oils and greases! So I checked their viscosities and matched the closest oils I could source myself - that will have to do. I would only be too happy if in the end I'd manage to get it working again but I have my doubts! Quote Link to comment Share on other sites More sharing options...
FxrAndy Posted October 5, 2012 Report Share Posted October 5, 2012 I am pretty sure that the balance cock from a swiss will not fit but depending on the balance spring attachement you may be able to use the balance and spring, the pinion should fit Quote Link to comment Share on other sites More sharing options...
*Aero* Posted October 5, 2012 Author Report Share Posted October 5, 2012 Actually the balance wheel is ok, its the escape wheel and oscillating pinion which are broken. The pinion I found it like that, but the escape wheel I broke it myself while screwing the mainspring bridge plate - the wheel shaft was not positioned correctly in the jewel and snapped, I actually heard it ! I need to be more careful next time! Quote Link to comment Share on other sites More sharing options...
FxrAndy Posted October 5, 2012 Report Share Posted October 5, 2012 I may have a 7750 that you can take the parts from if you want Quote Link to comment Share on other sites More sharing options...
Rolexman Posted October 5, 2012 Report Share Posted October 5, 2012 Without investing in proper oils, tools and a timing machine my guess is that this watch will never come back to life. Without some basic tools and knowledge about regulation it is sheer impossible to get it running accurate and stable. Sure with some luck you get it ticking. But there's more to it than that. It's a time keeper after all None the less a great practice! Quote Link to comment Share on other sites More sharing options...
*Aero* Posted October 5, 2012 Author Report Share Posted October 5, 2012 Well Rolexman, just about a couple of weeks ago I didn't have the slightest idea of what goes on in a mechanical watch, but after doing a fair amount research I managed to take the movement apart in the correct order and hopefully I'll be able to put it all together in the correct order! I'm by no means an expert, but if i manage to get the watch ticking again and keeping a "correct time", that will be an achievement for me...I'm not a watchmaker or repairer so I'm not going to give the movement a "by the book service" . I'll be happy if it will keep the time within -/+ 5min a day as this is not my everyday watch, but I will do my best to learn and get to know how to regulate the movement. Tools and oils are not worth buying at this stage - it's not worth the cost, I'll still be able to complete the job tho, I just want my watch to start ticking again!! Having said that any help and advice on how best to assemble and regulate the movement would be most welcome! Andy I sent you a pm re the 7750 for parts. Thanks for your help. Quote Link to comment Share on other sites More sharing options...
imajedi Posted October 6, 2012 Report Share Posted October 6, 2012 I did something similar to my Ebel Discovery 1911. Chrono broke a few weeks after I got it and I decided just to rip it to shreds and try and fix it. Fixed half the problem and ordered a eta replacement part for the broken piece. Received the replacement but have not tried reassembly yet. Best of luck to us all. Quote Link to comment Share on other sites More sharing options...
icoopernicus Posted October 6, 2012 Report Share Posted October 6, 2012 No experience with watch repair and jumping straight into automatic mechanical chronograph movement, that takes some nuts. Best of luck friend. Quote Link to comment Share on other sites More sharing options...
Rolexman Posted October 6, 2012 Report Share Posted October 6, 2012 I'll be happy if it will keep the time within -/+ 5min a day as this is not my everyday watch...., I just want my watch to start ticking again!! That's sort of a paradox. Proper cleaning and lubrication is the base of a well performing and accurate watch. It is like building a great V8 Chevy engine back together and the filling her up with 2 stoke oil.... If you know what I mean. You have come this far so it would be a shame if you get it back together but not running accurate. The +-5. Sec/ day is Chronometer accurate. A standard that is a great challenge even for the Swiss... You will have the biggest chance on a good outcome if you make sure all parts are very clean. Buy some Rodico cleaning gum and clean by hand or use a cheap Ultra Sonic cleaner (+-$30) and use dish washer soap and water and some Zippo lighter fluid to clean afterward (this will make the parts dry without rust). You are better of using NO oil than using the wrong oils. The 7750 is very sensitive to oil. If you use the wrong oil big chance you will not get it to perform accurate. Regulating the watch is a whole other ball game. Best to use some trial and error and monitor it over 24 hours and check with an atomic clock. If you use the search function you will find some posts over regulating and which studs to push on the balance assembly. Good luck and keep us posted! Quote Link to comment Share on other sites More sharing options...
*Aero* Posted October 6, 2012 Author Report Share Posted October 6, 2012 My reasoning was that the watch was dead - my choices were limited, either leave it dead and look at it as a nice bracelet , or send it for a service at a cost of over 200€ + parts, or somehow try to get it running myself! Btw I think you mis-quoted me, I said +/- 5 minutes per day not seconds! I'm not expecting to get anywhere near that accuracy But you're right re cleaning and oiling - that was in my plans, I had already stared cleaning the parts in acetone, ultrasonic cleaner I dont have, but seen some cheap ones on ebay - will consider getting one. Regarding oils I tried to match the viscosities of oils I have access to, but if no oil is better than the wrong type of oil I'll skip the oiling part. I got one type of oil my father uses for his grandfather clock its "Koch Uhrenol Sorte 1" but I don't know anything about it... When I come to regulating we'll see...the search function will come useful I guess. Thanks for all the help and advice - now I just need the parts to get on with it! Quote Link to comment Share on other sites More sharing options...
FxrAndy Posted October 6, 2012 Report Share Posted October 6, 2012 leave it dry and cleen, if you get it working then you obviosly have what it takes then it would be worth investing in a cleaner and some propper oils and leaning more Quote Link to comment Share on other sites More sharing options...
*Aero* Posted October 6, 2012 Author Report Share Posted October 6, 2012 I'll take your advice then, clean it and skip the oiling part.... is it ok to use acetone for cleaning? I can use other type of solvents, such as Isopropyl alcohol, MEK, white spirit etc. Quote Link to comment Share on other sites More sharing options...
FxrAndy Posted October 6, 2012 Report Share Posted October 6, 2012 Isopropyl alcohol is the pescribed suff here, put all the parts in a small jar filled with Isopropyl alcohol set that in the ultra sound filled with water, and turn it on for 30 min (never put a balance and assembly in an ultra sound or a main spring and barrel) apart from that you are good to go Quote Link to comment Share on other sites More sharing options...
Rolexman Posted October 6, 2012 Report Share Posted October 6, 2012 Stuff with Naphtha also works very well for a final clean. Quote Link to comment Share on other sites More sharing options...
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