Will not go face when down

[arkobugg]

Hello Mates, 

Im working on a Seiko movment 7619-1020, and when I have  cleaned it and oiled it. And are doing some testing, and it runs good laying with face down, but when I flip it over, it will not gor good. And almost stop.

Some ideas where to start searching ??

 

 

[jdm]

Do you have a timegrapher picture of when it "runs good"?

[arkobugg]

31 minutes ago, jdm said:

Do you have a timegrapher picture of when it "runs good"?

First photo is face down, second face up.

I have got it to go, with face up, when suddenley, its slowers down ...and I have to flip it over and sort of start the balance wheel again. And the it pick ups speed, and gos normal. 

[jdm]

It shows poor amplitude and pattern even when face down. So once you take it apart again you'll have to inspect very carefully balance jewels and pivots, especially cock side. Also replacing the mainspring could improve the situation.

[arkobugg]

1 hour ago, jdm said:

It shows poor amplitude and pattern even when face down. So once you take it apart again you'll have to inspect very carefully balance jewels especially cock side. Also replacing the mainspring could improve the situation.

I have allready found out that the main spring must be changed, but if Im going to inspect the jevel for the balance wheel cock side. What are the criteria for no go or what to be looking for, according to what??

 

[jdm]

6 minutes ago, arkobugg said:

What are the criteria for no go or what to be looking for, according to what??

That all parts that have friction has to look practically as new under a strong loupe.

[arkobugg]

4 minutes ago, jdm said:

That all parts that have friction has to look practically as new under a strong loupe.

And new looks like?    The hole must have nice and even ends, not jagged and the hole must be round not oval,,,,that kind of things or?

[rodabod]

Significantly different rate between du and dd makes me wonder if you have a hairspring issue, since 191 degrees amplitude is not horrendous.

[arkobugg]

Have now taken out the main spring, open the  barrel and inspected, looks ok. Put the lid on, took on of my small and strong plier, og sort og winded it up by hand some turns. And it feels strong and good. Or can a main spring be bad even if it feels good??   

Took out the jevel on the cock side, inspected in microscope. Looks like another jevels I have come a cross by doing service, dont know realy what I should be looking for??

Some with some good ideas?

 

[rodabod]

Look for a worn spot or pit in the centre of the jewel. 

But I still think you are most likely to have an oscillator problem as your rate varies significantly between DU and DD. How does the hairspring look?

One other quick thing to check is your balance end shake. This can affect the interface between the impulse pin and pallets in extreme cases, but is less likely to be an issue on a newer watch like this. 

 

[rodabod]

One thing I did not realise is that the second timegrapher photo only shows “good” amplitude because it is immediately when the watch is flipped over to DU. 

In which case carry on looking for sources of friction such as the balance end stone, balance jewel hole (is it cracked?) and end shake. 

Edited July 30, 2018 by rodabod

[Nucejoe]

Is one pivot shorter than the other? 

At this point, you have no access to the mainplate jewel , incab, you should see the pivots just sticking out from the jewels when you remove the cabs one at a time.

What is the end shake?  

My question for @jdm is, can you tell from the graph if the fork is hitting the roller plate?

[Nucejoe]

The pivot at bridge is likely to be shrot, with it,s cab removed you should see pivot's tip appear and barely above the jewel hole.

A regular test now is to lift one side of the wheel see if the pivot slides out of the jewels.