ETA 7750: Part 1 - Disassembly

okay so we're going to go through the disassembly of an ETA seven seven five zero movement and this is a tour no watch that I have here so I'm just opening the back up here and see the movement is running this watch was running intermittently and also had some issues with the day and date indicator so the first step here is I'm going to unscrew the screw that holds the rotor in place and I'm now going to remove that screw and then I'll remove the rotor itself well look what we see over here that is a screw head floating around in the movement and I can assure you that that is going to be contributing to some of the strange behavior that we are seeing with this particular movement so we'll have to find where that screw head came from now I'm inspecting around here first thing here I'm gonna remove the stem of the watch by pushing down on the release and removing it and this is the movement retaining ring and look at this this is a case clamp that's floating around so that screw head that we found was clearly holding this case clamp in place there's the top of the screw though there's the the shaft of the screw so I use a very small pin vise here and fortunately I'm able to grab the shaft of the screw and remove it and there's the screw get it into focus over here so we'll have to replace that I just use a piece of pith wood here to support the movement when as I turn the watch over and then lift the case right off of the watch next step is going to be to remove the hands that's the case gasket placing the stem back into the winding stem back into the watch and I just support the movement on its side keep pressure on the crown and I push with a pegwood I push in on the set lever so that I can get the stem all the way in use my version seven seven five zero movement holder you notice the day the Sunday over there is actually not aligned perfectly in the window that's one of the problems with this watch so I put a little poly bag over the dial here and I use my hand levers to prise the hands off of the watch you kind of want to rotate these in opposite directions to do this it's being careful not to damage the dial yeah remove the minute and well the second the sweep seconds hand cronograph hand came off already and there's gonna take the minute hand off being careful not to scratch anything and the hour hand now getting these small the the seconds indicator and the our recording hand and the minute recording hand you really need some really good small chronograph hand remover so these I believe are horotec levers and they are just small enough to get right underneath these hands and it's very gentle it's all it requires to free these up I mean really careful here not to damage the dial or the hands actually going to rotate the movement here just so I can get it oriented in a way that I don't have to kind of work with these levers in an awkward orientation that should do it a minute counter or a minute recording hand is the second hand our counter or our recording hand and the next thing I noticed here is actually the dial itself which needs to be removed or by operating to release levers the dial is actually really loose you can see it almost coming off here and actually I'm able to remove the dial without manipulating the release mechanism which is actually one of the issues here I believe that the day indicator is floating around with that's where that's the day where the Sunday is is actually coming up and it's because the dial is too far away from the the day indicator it's not being secured properly so I'm removing the day indicator now and the next thing we're going to do is we're gonna remove the this is called the date indicator maintaining plate so as it sounds date indicator is the the the numeric date indicator this is the maintaining plate it keeps it in place by extending over the teeth that are on that date indicator I should remove that double character I'm gonna manipulate it here in a sec right here this is the double corrector just to see how it's oriented and you're gonna notice in this video I don't remove it here but I not sure why didn't do that it is free to kind of come out right now of whatever reason I left it in there forever for a minute so next we're gonna remove the other maintaining plate and this second maintaining plate here to the right of the screen is called the date jumper maintaining plate and this also holds the date ring in but it more importantly it holds the the jumper the jumpers both after the day and the date jumper as well as the damn date jumper spring you'll see this you do need to be careful removing this sometimes that bring can be loose and you don't want it to ping away so do this with some some caution these are very small screws so being careful not to to lose those screws and here's the plate and I use that peg wood just to make sure and you'll notice here that the date jumper itself is actually attached probably some oil to this maintaining plate it's literally it's just stuck on there so I just kind of you know move it off and it was held in there just by some some oil that was the date jumper that I just removed and let's get rid of the maintaining plate in the next course of business here and I use some one some one touch to hold that spring in place that's the the jumpers the day and date jumper spring and I use that one touch to make sure the rod ACOTA to make sure it doesn't ping away I remove that and now I can remove the day jumper okay and that's also held in there pretty good by some old lubrication but I've got it off and now I'm gonna get rid of that the double corrector this double corrector is what's used when you move the winding stem or the crown to the middle position to quickly set the day or the date so now the actual date ring is free to be removed and there it is can be really gentle with that make sure you want to scratch it and next we can remove the calendar platform itself this large plate is called the calendar platform it's secured with three screws and we will remove it and these screws are kind of recessed pretty good in the plate so they're a little hard to get out so I just loosen them all up and remove the plate and then just kind of dump the screws out I just want to make sure you're gentle and you don't want these screws to fly all over the place and a relative basis these screws are pretty large I use a screwdriver here just to kind of pry this counter platform up there are a couple locations around the edge of the movement where there space in there that you can get that screwdriver in there nice and easy and you got to do this really gently and there we go so I can figure out a place to grab this counter platform and now I'm just gonna gently turn it over and recover the three screws and then go you'll notice also right by my thumb there there's a very small spring I'm gonna be careful not to break that that spring is used the double corrector that's a double corrector or I'm not sure what it's called but I would call it a double corrector spring maybe it's a double corrector return spring I'm not 100% positive okay and here is the the calendar work so and the motion work and you'll you'll you'll note rather the motion work you'll note that the the the day corrector wheels here the day and date Drive wheels are not actually oriented properly you know there's this mark on the movement plate here for the day driving wheel that is supposed to be lined up with this line I'm setting it in that position right now okay I think so and now when it when that one is in position the date jumper the date driving wheel is supposed to point right at the can opinion so it wasn't in the proper orientation and what that means is that at midnight the day and date will not both simultaneously advance so this what I'm doing here is just showing you the proper orientation of these two wheels with respect to each other so that they will flip over at midnight pretty much around the same time or within a few minutes maybe ten minutes of each other this is the proper orientation for when we reassemble it so now back to disassembly I'm going to remove Oh first over here these this over here these two items here are the you know the dial retaining clips that remember I didn't have to move these out of the way to release them to remove the dial which I believe is a problem I'm going to have to you know troubleshoot that I will most likely have to create new dial feet and solder them onto the style I think they're too probably too narrow so let's get back to the disassembly here I'm gonna use this a little piece of peg we're just here to make sure I don't lose the spring over here first thing I'm going to do is remove the that is the our counter otherwise known as the our counting wheel next is the our hammer spring and that's really pretty easy to remove right now just comes right off you have to be careful with the orientation next up that's the our hammer itself okay trying to find a good place to grab it and this is the our hammer it's used to reset the our counter back to to zero and this over here is the our counter lock and this keeps the our counter locked at the zero mark when appropriate you know we here I put this in the slow motion this is the yeah you'll see it just flung away there in slow motion that is the what do we call that piece the our hammer operating lever so that just flung away from me because I grabbed it very poorly yeah but I found it again and now I'm gonna remove the day and date driving wheels you just come right off next up is the our wheel and the free can opinion is inside is again there's a little bit of lubrication in there that's holding it in so I'm just gonna push it out so you can see it so there's the our wheels gonna come off here hello and the free can opinion will come off next and then we have the unit wheel and we have the intermediate date wheel the intermediate date wheel and you'll remember I as I just pointed out you have the this is a free cat opinion it is not it doesn't require can opinion remover to remove it floats freely on that center post so this has what we call a driving opinion which I'm gonna remove now with actually these are kind of a roller remover but you can see there are some indentations in here you gently pry this driving pinion up and this is what gives the Train the appropriate amount of friction to drive the the the motion work and on the back of it there is a little spring that you can see here and that allows it to slip so that you when you use the whining stem to set the hands you can do that without fouling up the the train of wheels okay so it's time to turn the movement back over to the dial down position and for the 775 oh I prefer to use this relatively inexpensive plastic movement holder I think it does a better job you want to make sure that the movement is fastened in here securely so I use a couple pieces of pegwood to press it down into place so first off we're going to remove the balance so I unscrew the balance over here it's got one screw I'll take that out and then we just carefully lift off the balance and make sure that we don't foul the hair spring as we remove the balance assembly and the hair spring as well and what I do is I just put it down and flip it onto its back it's more secure that way and put the whole thing in my parts tray okay so now before we remove the automatic device bridge we have to release any tension that may be in the automatic winding unit so there is a very small stop click spring here that I'm just holding the winding crown and releasing that spring and then letting it slowly wind down this is the hammer spring which puts pressure on the hammer that's used to reset the chronograph in a minute counter to the zero position a lot of tension on this spring but it comes off pretty pretty easily and then just manipulate it so that it is released next up I'm going to remove the clutch spring you just pull that right out the clutch spring and now I should be able to unscrew the three screws holding the cronograph bridge in place I'm sorry the automatic device bridge will get to the chronograph bridge in a little bit okay and we'll lift off the automatic device bridge you can see I'm bringing along with it the reduction wheel so I'm just gonna use my peg wood to put to keep that reduction wheel back kind of sorta in place that's the automatic device bridge I'll remove now the reduction wheel the reversing wheel be very very delicate part here and now I can remove the hammer so the hammer comes out now this is the clutch clutch is used to engage and disengage the chronograph mechanism the cronograph wheel which is what drives the chronograph seconds hand underneath here there is a friction spring for the chronograph wheel it just comes right out it's a plastic part so you can't put that in the ultrasonic cleaner like the outer wheel lock on the other side that exposes the oscillating pinion and I'll show you the orientation of the oscillating opinion because it's got you know different you know to make sure you put it in the right way a little wider on the bottom next this is the minute counting wheel or the minute recording wheel and the chronograph minute hand attaches to that and this part here is called the lock and it's what locks the minute minute recording wheel in place and before I do anything with that lock first I'm going to release the tension on the mainspring by holding the clickspring back well first I'm going to keep pressure on the front winding stem the crown I'm removing I'm pulling out the clickspring and letting the power in the train in the mainspring down you know in a controlled fashion and now all of the power is out of the mainspring and I'm now free to remove the pallets so I will move first the pallet bridge and you often hear of this referred to as a pallet but since it has two screws it's actually a pallet bridge a has one screw so I'm removing the two screws on the pallet bridge and the pallet bridge comes up pretty easily and that exposes the pallets carefully grip the pallets by the shaft and take that out of the way and now I am removing the chronograph bridge there are three screws that hold the chronograph bridge in place sorry two screws and I can now gently remove that chronograph bridge or chronograph plate and yeah usually this does require a little bit of finesse so I use a little screwdriver there's a couple spaces under this plate that allow you to kind of prise it up just being very careful over here and there we go I always have to find a good place to grab this and that is your chronograph plate this is the ratchet wheel driving wheel and again back to that lock so now I'm going to unscrew the screw fastening the lock in place and gonna release the pressure on the lock see here it's got a little bit of a tension spring attached to it so I'm gonna hold down a little wrote eco on top of the lock and then release the tension there you go now it can easily be removed and that frees up the minute counter driving wheel so this wheel has a jewel in the center of it the minute counter driving wheel and note the orientation here now we can free up let's see the cam jumper well actually before I do that I'm going to press the operating lever such that I can get the cam into the appropriate position to make it easy to remove this cam jump or spring so use a very sturdy pair of tweezers now you can see it takes a little bit of effort here to remove the pressure but there I have it and now if you just you know carefully manipulate it you can remove it from the two posts that hold it in place there we go this is the operating operating lever screw here this screw I believe is the same screw that's used to fasten the same type of screw to fasten the cam in place but I'm removing the operating lever now and once the operating lever is out of the way I can see you can see the operating lever spring exposed now and I can take a get a grip on that operating lever spring and kind of slide it out of the way and now remove it and I'll show you the appropriate orientation of that operating lever spring make it easier to put it back in later this part is called the d tunt have to sharpen my tweezers here and as the D tante comes right out and now I can remove the cam and this chronograph cam is what controls all of the hammers reset to reset the chronograph mechanism and to start the chronograph mechanism etcetera it's called a cam with a screw remember I said the screw is very similar I think it's identical to the operating lever screw and when we remove the cam we will be able to see the crown wheel underneath it the crown wheel is actually comprised of a crown gear in a core that's the core they just touched over there that's the click spring next I'm gonna remove the ratchet wheel the ratchet wheel is you know the other side of that is the mainspring barrel the ratchet wheel is what actually winds the mainspring in that click spring off to the right makes it so that the ratchet wheel doesn't unwind this is what we used to release the tension in the mainspring earlier that's your ratchet wheel you can see the mainspring arbor there mate beneath it now these two small screws secure the crown core so I'm going to remove the crown core okay and the crown wheel is trying to come up with it so I'm just gonna use a piece of PEG wood to keep the crown wheel in place that's the core and that's the crown wheel that second operating lever at the bottom is actually riveted to the barrel bridge so we won't be removing that lever now I'm just gonna unscrew the remove the screws that secure the barrel bridge in place and then I can't move I'll remove the screws it's three of them and now I can remove the entire barrel bridge there you go that is the barrel bridge okay now we can start removing the train of wheels so first we'll remove the great wheel or the center wheel this is the third wheel the fourth wheel or the seconds wheel and the escape wheel and of course last but not least well first this is the stop lever that is what halts the movement when you pull the crown out to set the times you can set the seconds exactly and this is the barrel bridge I'm sorry the barrel means ring Brown not the bridge that's the ends IRA mainspring barrel and here we're left with the the main plate I'm going to reverse it back to the dial up position and when again when it's in dial up position I prefer to use the Bergeon holder movement holder and I can start disassembling the keyless work and we start with removing the setting lever jumper or the set leaver jumper spring setting leaver spring I take the tension off of the spring with a sturdy tweezer now I can remove the screws and it won't jump away from me these are very small screws here screw number two and the setting lever jumper comes out and I have to kind of slide it off of that intermediate setting wheel I'll remove that intermediate setting wheel now this is the time setting gear these things all have different names and different watches just call it an intermediate setting gear whatnot next up we remove the setting lever and now I can pull the winding stem and crown out and a little bit of pressure on the yoke so when I touch this the winding pin and the sliding pinion kind of just fall into the movement holder you can see that pressure on the yoke there I'm now gonna remove that yoke and this part here is called a rocking bar but before I mess with that I'll find my sliding pinion and winding pinion and let's go back put the movement back into the holder now I can remove the rocking bar and the rocking bar is under pressure from that yoke spring that you see here and I that also applies pressure to the yoke itself and I just leave that in I don't take that out when I do a 775 zero and that completes the disassembly that is a disassembled ETA seven seven five zero

Channel: Stuart Stakoff

Views: 29,493

Keywords: 7750, ETA 7750, Valjoux 7750, chronograph, watch repair, watch disassembly, watch overhaul, chronograph repair

Id: RYNeRiDdPQE

Length: 34min 10sec (2050 seconds)

Published: Sun Mar 15 2020