Certina 28-451

[chrisdt]

Have recently purchased an old Certina 28-451 Automatic..Runs sweetly..Keeps excellent time, has good amplitude.

If wound by hand and leave on the bench it runs for around 36 hours. I f I wear it it still runs for about 36 hours and then stops.

I have checked the auto mechanism which seems to be working ok checked the rotor not fouling the case etc...Any suggestions

please...Thanks

[Nucejoe]

Apparently you have bought someone's problem. He will be feeling miserable  when you fix this watch.

You ought to keep eliminating all that can be eliminated one at a time.

Eliminate dial plate.

Eliminate date complication.

Check the barrel- mainspring.

Bent or worn pivot, damaged pinion leaves and gear teeth, check shakes and jewels. who knows there is a fault somewhere that has frustrated bunch of folks.  But we'll fix it.

Cheers 

 

 

 

 

 

 

[watchweasol]

Hi So you bought the watch, do you have any history on it ?   So we don’t know when it was last serviced if at all. I would suggest that in the first instance it needs a service and inspection of the parts  and re testing. You can then start from a known point and re asses the watch from there.

[Nucejoe]

23 hours ago, chrisdt said:

If wound by hand and leave on the bench it runs for around 36 hours. I f I wear it it still runs for about 36 hours and then stops.

I guess  I am dumber than you think.

Does auto winder not wind at all ? 

[chrisdt]

No. If I just wear it after it stops it will not run but the auto wind mechanism seems to be ok

[RichardHarris123]

The automatic works can't be working.   I don't know what the issue is but it's definitely not working. 

[JohnR725]

1 hour ago, chrisdt said:

No. If I just wear it after it stops it will not run but the auto wind mechanism seems to be ok

there's only two ways to supply power to this watch either by hand winding or the automatic. If you wind it up by hand and it runs for 36 hours and runs out of energy stops. If you put it on your wrist and it still runs out of energy and stops it tells us the automatic is not working at all. Ithen I assume if of wind it up every 24 hours it runs continuously? Unless you're trying to tell us that it runs for 36 hours and stops no matter what then would have to find out what causes it to start again?.

I don't suppose you have access to a timing machine?

On 7/12/2023 at 1:47 PM, chrisdt said:

Have recently purchased an old Certina 28-451 Automatic..Runs sweetly..Keeps excellent time, has good amplitude.

did you purchase this as a running watch or was it just sold as is?

[chrisdt]

If I introduce power by hand winding and wear it it will run for around 36 hours and then stop. It will

not start again by wrist movement. It was purchased with several others at a local auction house

(as found)

[HectorLooi]

2 hours ago, chrisdt said:

auto wind mechanism seems to be ok

How did you determine that the autowind mechanism is working?

If you watch the mainspring barrel while rotating the rotor manually, can you see the ratchet wheel moving? Then reverse the rotation direction and observe. 

[Nucejoe]

 Let forget the selfwinder as if this is  just a hand wind watch, now if you hand wind it eveyday? does it keep on running and not stop at 36th hrs ? 

A simple yes or no.

Edited July 20, 2023 by Nucejoe

[chrisdt]

A simple yes

[Nucejoe]

So, its the auto winder which everyone has been saying all along.

Examine every pivot, gear teeth and  hole jewel  ,spring in autowinder, does the axle tilt? is it worn?  worn the bushing in the rotor? 

Good luck.

[chrisdt]

On 7/20/2023 at 11:47 PM, HectorLooi said:

How did you determine that the autowind mechanism is working?

If you watch the mainspring barrel while rotating the rotor manually, can you see the ratchet wheel moving? Then reverse the rotation direction and observe. 

Yes HectorLooi ... The ratchet wheel revolves while moving the rotor in either direction but does not impart any power to start the watch going only the crown does that

[JohnR725]

4 minutes ago, chrisdt said:

The ratchet wheel revolves while moving the rotor in either direction but does not impart any power to start the watch going only the crown does that

Time for the experiment. Place a felt pen Mark on the ratchet wheel you can see easily how many rotations it's making. Then how many turns of the crown does it take to move the ratchet wheel and that what time does the watch starts to run. So basically what you're looking at is how much of the ratchet wheel has to be wound up before the watch runs. You'll also note that the number of turns the crown to do that soon be considerably less than the automatic.

Now for the automatic part rotate the automatic how many times you have to rotate the automatic to get the ratchet wheel to wind like one turn. Or whatever it takes to get the watch  to work because you're going to find it's going to be a lot you can't just shake it and instantaneously have you might have it started up but you won't have enough power to run for The very long

Which is typically why when you get stopped watch the recommendation is to manually wind it a little bit before letting automatic hopefully do something

let's give you an example of some of this this comes from Seiko is not going be exactly the same. As you can see in this example 55 turns out the crown to wind the watch up which is equivalent eight turns the ratchet wheel when you are using  screw. Then you notice the part about the automatic there recommending getting some sort of machine because it's going to take a whole lot of that to wind up the watch.

 

 

[chrisdt]

Thanks for your detailed reply JohnR...I think a strip down is the only way forward because no matter how many times the rotor is turned and despite the ratchet wheel turning correctly the click is not put under tension.

[Endeavor]

Of course you can strip the whole watch, if you deem that's required. Often auto-works are like an additional package on top, so if you don't want to strip the whole watch (since it seems to run fine), you could perhaps limit the strip to the auto-works and see if you can fix that?