7A28-7020 Restoration so far.
Jul 18, 2017 16:31:28 GMT -8
Groundhog66, HiBeat, and 12 more like this
Post by pip on Jul 18, 2017 16:31:28 GMT -8
Blimey. Just spent half an hour typing this up, one glitch on my laptop and here I am starting all over again. As annoying as what follows...
I recently bought a non running 7A28-7020 (Seiko quartz chrono with no piddly plastic gear trains, it's all quality stuff as befits 'the world's first analogue display quartz chronograph') which actually turned out to have a working time function although none of the chrono functions worked. The 7020 is aka the Bond watch as Roger Moore wore one in View to a Kill (albeit his had a white dial and mine is black). Popping it out of the case from under a very battered crystal showed a nice clean dial although people who know this model will already see a problem.
Popping off the hands and removing the two dial screws shows what is underneath.
Turning over to the movement side, there are seven screws that hold the antimagnetic shield plate in place.
And here is the reverse of that plate, showing that the pcb came off with it.
All looking nice and clean here.
I think here I should have removed the green circuit block spacer. But I piled into the chrono seconds bridge instead.
And finally remove the spacer.
See that mess at 2? That used to be a switch lever like the one at 11. The one at 5 has started to go but I hoped to recover it with some tlc. The one at 2 broke up on removal but luckily for me, Paul from the 7A38 forum very kindly donated me one of his spares.
Rotors all look ok. On testing, all of them are in spec for this model.
Chrono minute bridge removed showing the wheels and step rotor underneath all seated around the horseshoe shaped rotor stator.
Same at the top of the movement for the 5/100 chrono bridge.
Removing the train wheel bridge shows why it can be hard to get this bridge back on... that's a lot of pinions to line up.
Nearly there. Keyless works next, then the black setting wheel spacer. Followed by centre wheel and pinion.
Which leaves me with a bare main plate and lots of parts.
All the parts were cleaned by hand and in the US, and on rebuild I (largely) followed the oiling points in the service guide. Getting the train wheel bridge on was remarkably easy (beginners luck), even second time around when I realised after almost completing the rebuild that I'd not put the setting wheel back in.
Then I had awful trouble getting the smaller bridges back in place. Try as I might I just could not get the 5/100 counting wheel or the minute counting wheel to sit. I tried for an hour at at time, over the course of several days, could not get it done. Hunted down videos to watch. You know what it was? I had the movement sat too low in the holder and the long shafts of those were fouling against the holder. Always check the simple things Pip!
So that corrected, I got the rebuild under way. All the way back to getting the dial on. Ready to chuck a battery in and watch it spring to life. Battery goes in and... nothing. Checked the battery - below spec! Grabbed a ticking 7A38 form my box and nicked the battery, checked it anyway and it's in spec. Put it in and... nothing. Pulled it apart again, checked the gear trains. Each of them moves easily and engages the other wheels so it's not jammed. Recheck the coils in case I'd caught one of them. All in spec.
My best guess at the moment is an electrical issue with no power getting to the right places. I can't work out quite how to test this as my multi-meter doesn't seem to have the settings that the Seiko one has. Perhaps I have mishandled the pcb and damaged it. Looks ok to me but I don't know the telltales to look out for. At the moment I am stumped.
But I will get there, and I will revive this piece.
Big thanks have to go to Simon aka siralan as he has given me a lot of encouragement, some good tips and stopped me going horribly wrong at one point. It was reading his excellent and very clear posts on servicing 7Axx movements that got me interested in them in the first place.
This thread will be resumed - hopefully very soon when I work out what I need to correct.
I recently bought a non running 7A28-7020 (Seiko quartz chrono with no piddly plastic gear trains, it's all quality stuff as befits 'the world's first analogue display quartz chronograph') which actually turned out to have a working time function although none of the chrono functions worked. The 7020 is aka the Bond watch as Roger Moore wore one in View to a Kill (albeit his had a white dial and mine is black). Popping it out of the case from under a very battered crystal showed a nice clean dial although people who know this model will already see a problem.
Popping off the hands and removing the two dial screws shows what is underneath.
Turning over to the movement side, there are seven screws that hold the antimagnetic shield plate in place.
And here is the reverse of that plate, showing that the pcb came off with it.
All looking nice and clean here.
I think here I should have removed the green circuit block spacer. But I piled into the chrono seconds bridge instead.
And finally remove the spacer.
See that mess at 2? That used to be a switch lever like the one at 11. The one at 5 has started to go but I hoped to recover it with some tlc. The one at 2 broke up on removal but luckily for me, Paul from the 7A38 forum very kindly donated me one of his spares.
Rotors all look ok. On testing, all of them are in spec for this model.
Chrono minute bridge removed showing the wheels and step rotor underneath all seated around the horseshoe shaped rotor stator.
Same at the top of the movement for the 5/100 chrono bridge.
Removing the train wheel bridge shows why it can be hard to get this bridge back on... that's a lot of pinions to line up.
Nearly there. Keyless works next, then the black setting wheel spacer. Followed by centre wheel and pinion.
Which leaves me with a bare main plate and lots of parts.
All the parts were cleaned by hand and in the US, and on rebuild I (largely) followed the oiling points in the service guide. Getting the train wheel bridge on was remarkably easy (beginners luck), even second time around when I realised after almost completing the rebuild that I'd not put the setting wheel back in.
Then I had awful trouble getting the smaller bridges back in place. Try as I might I just could not get the 5/100 counting wheel or the minute counting wheel to sit. I tried for an hour at at time, over the course of several days, could not get it done. Hunted down videos to watch. You know what it was? I had the movement sat too low in the holder and the long shafts of those were fouling against the holder. Always check the simple things Pip!
So that corrected, I got the rebuild under way. All the way back to getting the dial on. Ready to chuck a battery in and watch it spring to life. Battery goes in and... nothing. Checked the battery - below spec! Grabbed a ticking 7A38 form my box and nicked the battery, checked it anyway and it's in spec. Put it in and... nothing. Pulled it apart again, checked the gear trains. Each of them moves easily and engages the other wheels so it's not jammed. Recheck the coils in case I'd caught one of them. All in spec.
My best guess at the moment is an electrical issue with no power getting to the right places. I can't work out quite how to test this as my multi-meter doesn't seem to have the settings that the Seiko one has. Perhaps I have mishandled the pcb and damaged it. Looks ok to me but I don't know the telltales to look out for. At the moment I am stumped.
But I will get there, and I will revive this piece.
Big thanks have to go to Simon aka siralan as he has given me a lot of encouragement, some good tips and stopped me going horribly wrong at one point. It was reading his excellent and very clear posts on servicing 7Axx movements that got me interested in them in the first place.
This thread will be resumed - hopefully very soon when I work out what I need to correct.