Troubleshooting low amplitude

[DavidADav]

Hello watch gurus,

I have a pesky issue I’ve been working to troubleshoot and could use some advice. The movement is a Seiko 2205 that I’ve been working to overhaul.

The movement was not running when I received it, as the hairspring was fouled. I disassembled, cleaned, and inspected all parts. There was some buildup on two pinions, which I resolved, and I replaced the hairspring. Post assembly the amplitude is painfully low (130), and the timing is variable, as expected. 

I assumed I did something wrong, so I stripped it down and cleaned it again, inspecting all pivots, jewels, etc. Post assembly (manually winding the movement) I have the same results. 

I epilamed the escape wheel and pallet jewels, and used 9415. 

Inspecting the balance I see a very slight tilt to the hairspring which I need to correct, but I wouldn’t expect it to cause this behavior as the hairspring is not touching the balance bridge. 

The only thing I did not do with this service is to disassemble, clean, and grease/oil the barrel and mainspring, as this is one of those “thou shalt not open” Seiko barrels that is stinkin impossible to open. However, I think this has to be the cause. 

Any ideas? Does my conclusion sound correct?

 

Thank you for your time. 

[Nucejoe]

Add power to barrel manually, I use a tooth pick to push a teeth of the barrel to turn it, then observe the amplitude.

The mainspring in your watch has probably never been replaced with new one. 

[DavidADav]

5 minutes ago, Nucejoe said:

Add power to barrel manually, I use a tooth pick to push a teeth of the barrel to turn it, then observe the amplitude.

The mainspring in your watch has probably never been replaced with new one. 

Thank you, I will try that. However, after saying all of this, I think I may have a larger issue. I drained all power and now found that the balance won’t start even after 30 turns of the crown, so something is up with my gear train. I will continue troubleshooting…

Apologies for the noise - this service wasn’t as complete as I thought it was! 
 

Dave

[Nucejoe]

 First low amplitude and it wouldn't start when manually powered, perhaps an excessively heavy lock on pallets. It would lock in case escape wheel is overpowered, in which case mainspring is still a suspect.

I would remove the auto device and try turning a gear of the train you have access to.

Considering that you manipulated the hairspring, are you sure impulse jewel is in beat.

 

 

[JohnR725]

3 hours ago, DavidADav said:

I replaced the hairspring.

you replace the hairspring or the balance completes?

with the balance wheel removed and the pallet fork removed how does the gear train spin?

 

[rodabod]

Check the side-shakes of the wheels, especially the barrel and centre wheels.
 

And generally check that the train runs free with the pallets removed, and also that the balance oscillates freely. 

[clockboy]

I have found low amplitude an issue with many Seiko,s  I have  serviced. However 130 is way too low, it could well be the mainspring I suggest replace and test again.

[jdm]

25 minutes ago, clockboy said:

I it could well be the mainspring I suggest replace and test again.

The OP did that already.

In most cases low amplitude is due to faults with the balance, hairspring or escapement.