Seiko 6349a weird seconds hand fault

[quantieme]

Hi all, I have this seiko that I got as a non runner, I stripped it cleaned it serviced it and fitted a new mainspring and put it on an auto watchwinder and it ran ok for two weeks. I took it off and wore it then it started gaining time like 20 mins in a couple of hours and I have noticed that about every 10 to 20 seconds the seconds hand has a little spurt and suddenly moves on by 2-3 seconds hence the gaining time. I have never come across this before so any ideas as to the cause. Thank you in advance Tony 

[anilv]

Does the 'spurt' occur at regular intervals?  It could be wheels binding due to a bent pinion.  I would look closely at the interaction if the pallet fork and escape wheel. 

Anilv 

[jdm]

I can't know what is wrong with the mov.t but incidentally let me note that (at least) the dial fakeness sticks out.

[quantieme]

5 hours ago, anilv said:

Does the 'spurt' occur at regular intervals?  It could be wheels binding due to a bent pinion.  I would look closely at the interaction if the pallet fork and escape wheel. 

Anilv 

it seems to be as i say anytime between 10and 20 secs you get the little spurt of 2 to 3 secs, i think i will have to take it apart again and check the pinions.

[quantieme]

4 hours ago, jdm said:

I can't know what is wrong with the mov.t but incidentally let me note that (at least) the dial fakeness sticks out.

i know the dial has been refinished the seller listed it as a repainted dial and i could see that anyway but i liked it so i bought it.

[anilv]

I usually remove the balance, give the mainspring a wind and see if the pallet fork snaps from side to side when helped with a oiler. Then I remove the pallet fork and check if the wheels spin true with no wobble. You can also observe endshake as well.

If the watch is very dirty a dunk in lighter fluid for a few minutes will help loosen the old oil. Remove day and date-wheels as well as any other plastic parts first.

The reason I do this first before cleaning is that sometime you find issues which render the watch not worth fixing unless you have parts. Nothing worse then cleaning a watch and then finding a fault which brings everything to a standstill!

Checking as you dismantle saves unnecessary work.

Anilv

[quantieme]

8 hours ago, anilv said:

I usually remove the balance, give the mainspring a wind and see if the pallet fork snaps from side to side when helped with a oiler. Then I remove the pallet fork and check if the wheels spin true with no wobble. You can also observe endshake as well.

If the watch is very dirty a dunk in lighter fluid for a few minutes will help loosen the old oil. Remove day and date-wheels as well as any other plastic parts first.

The reason I do this first before cleaning is that sometime you find issues which render the watch not worth fixing unless you have parts. Nothing worse then cleaning a watch and then finding a fault which brings everything to a standstill!

Checking as you dismantle saves unnecessary work.

Anilv

i am going to dismantle it again and check it a bit at a time, thanks for the tips.

tony