Seiko 2906a - possible balance issue

[Michalzeszen]

Hi there.

This is only my third service, as I am learning this practice. Admittedly, I shouldn't have got such a small movement to service, but there we are. I have cleaned, assembled, and oiled it successfully, but the watch will not run.

Watching the video above, can you point me to some causes? I have access to a new balance with a balance spring, but unfortunately, I don't have the tools or skills to replace it. If you could point me to a new balance complete, I'd much appreciate.

 

[RichardHarris123]

Firstly remove the balance and check that the pallet fork (lever) snaps back and forth will a gentle push.

If it does then power is getting through to it and then balance is where the fault lies. 

[AndyGSi]

The other thing is to try the balance on its own without the fork and see how is oscillates.

[Michalzeszen]

1 hour ago, RichardHarris123 said:

Firstly remove the balance and check that the pallet fork (lever) snaps back and forth will a gentle push.

 

Pardon. I forgot to mention that yes, the pallet fork snaps back and forth without the balance.

1 hour ago, AndyGSi said:

The other thing is to try the balance on its own without the fork and see how is oscillates.

This is where I get confused. Even though I can't find any problems with the balance spring (it seems perfectly aligned), but balance is oscillating only 5-7 times. From what I can tell, it should oscillate much more.

I'm narrowing it down to the pivots, which is a pain because I really cannot replace it by myself.

[AndyGSi]

Yes it should oscillate more than that.

Have you tried loosening the balance cock.

Can you post close up photos of the pivots and also have you checked the jewels.

[Michalzeszen]

On 3/2/2025 at 6:51 PM, AndyGSi said:

Have you tried loosening the balance cock.

What do you mean by that? Loose the screw or the pin that holds the hairspring?

 

On 3/2/2025 at 6:51 PM, AndyGSi said:

Can you post close up photos of the pivots and also have you checked the jewels.

Not the best pictures. At night I'll try better lightning.

https://photos.app.goo.gl/eEGTh4LYuSw8E5rf8

[RichardHarris123]

This one. 

[Zonablazer]

Did you remove the jewels from the balance to oil them? Could you have possibly placed the jewels back incorrectly and it is applying pressure to the balance staff?

Some jewels have a domed side and a flat side. If the domed side was placed the wrong way it would apply too much pressure to the staff and the balance will not move. If this is the case and it has a kif setting on the other side of the movement I would check it as well.

[Michalzeszen]

10 hours ago, RichardHarris123 said:

This one. 

 

Oh yes. Since cleaning and reassembling everything, I have played with this screw multiple times.

10 hours ago, Zonablazer said:

Did you remove the jewels from the balance to oil them? Could you have possibly placed the jewels back incorrectly and it is applying pressure to the balance staff?

Before posting this thread, I revised the jewels and they were quite dirty with old oil, but the cleaning and reassembling were meticulous. I have watched several videos of this process before executing it and the oval side of the jewel was my main concern. As well as aiming the little oil droplet. lol

I have better pictures, which don't help because I can't spot anything wrong.

[nevenbekriev]

What You need to check is if the hairspring, when the balance is in the movement, is not resting on the balance arms. So You need to look at the spring from a side and it must be parallel to the balance/cock, there must be safe distance between it and the balance arms and the cock.

[clockboy]

Looking at the first vid it looks like the outer coil is touching the next inner coil. First step is to remove the balance and soak in a de greaser and dry . Once dry de magnify the balance re fit and test.
if no improvement inspection under strong magnification to see the fault.

[JohnR725]

5 hours ago, Michalzeszen said:

I have better pictures, which don't help because I can't spot anything wrong.

I assume this is what you mean by a better picture and you can't spot anything wrong in this picture? Yes I know the tool was made specifically to do this but some hairsprings really do not like to be stretched in this method. Then the place where you are having a problem with your balance wheel is in the watch not here which is why you won't see a problem typically. 

On 3/2/2025 at 11:33 AM, Michalzeszen said:

This is only my third service

What was the watch doing before you serviced it?

On 3/2/2025 at 1:32 PM, Michalzeszen said:

This is where I get confused. Even though I can't find any problems with the balance spring (it seems perfectly aligned), but balance is oscillating only 5-7 times. From what I can tell, it should oscillate much more.

I'm narrowing it down to the pivots, which is a pain because I really cannot replace it by myself.

I suppose we need a definition of what perfectly aligned means and let me quote something down below to help with that.

2 hours ago, nevenbekriev said:

What You need to check is if the hairspring, when the balance is in the movement, is not resting on the balance arms. So You need to look at the spring from a side and it must be parallel to the balance/cock, there must be safe distance between it and the balance arms and the cock.

Usually one of the biggest problems for everyone in watch repair is the hairspring.  Is truly amazing how much energy is lost when the hairspring is not where it's supposed to be. 

 

[Michalzeszen]

Hi there.

Bad news. I had a domestic accident in the kitchen and severed nerv and tendon of my index finger. I'll be away  from the hobby for at least two months.

Good news. I have found a brand new balance with pivot. The great challenge here will be installing the hairspring on the bridge, but at least I have the part.

[HectorLooi]

Take care. Praying that you'll heal well.