Tissot `Seastar` help please.

[Tricati15]

My 60`s Tissot `Seastar` watch with an 871-1 movement has never kept good time, (gains a lot), except that is, the first week in my possession: after that it was gaining many hours over a 24 hr period. A visit to a watch repairer revealed a small blob of oil on the spring, shortening the balance spring movement. It was duly `serviced` which remedied the situation, only for it to start gaining once more after a week or so. This time, I decided to examine it myself. I couldn`t find anything wrong with the balance movement but decided to change the balance wheel and spring for a new replacement (Renata), purchased from a Mediterranean source on ebay. On examination, the end of the spring that`s supposed to be shaped (which wasn`t) to fit inside the advance/retard lever, isn`t tempered: ( please see drawing): the slightest touch of this part of the spring puts a kink in it....and to be honest, even if I was able to apply the  correct shape, there was no way with the magnifying optics I had at the time (a Swiss made x8 loupe), enabled me to determine if the `shaped` part of the spring sat correctly in it`s R/A lever.  So I decided to purchase a x15 clip-on eye glass from a recommended outlet (Cousins) , only to be told by them that they dealt with trade only!  I bought the identical one elsewhere, only to discover that in reality, the magnification was x8 and not 15.

The original balance and spring has been replaced now, along with it`s inherent 2 hrs a day gain. Does anyone have a suggestion please?                      

IMG_20160714_0001.pdf

[sstakoff]

Well, for one thing, moving the #2 lever will set the watch out of beat in addition to impacting its timing. Think of a watch "in beat" as having equal length tics and tocks, if that makes sense. There are a number of factors that could contribute to a fast watch, but we would also need to understand the current amplitude of the watch - that is how far round the balance rotates on each oscillation. The best way to measure these parameters is with a proper timegrapher.

 

[Cad101]

Yep as sstakoff says you really do need timergrapher to set the balance in beat to start trying to work out what could be making the watch gain so much time.

[sstakoff]

You could get the balance in beat in another way, but be warned that if you are not experienced working inside the movement you are at extreme risk of doing some very serious damage. The escapement is one of the most delicate parts of the watch. Having said that, to get the watch in beat:

1. Remove the balance
2. Properly let the power out of the mainspring. Do this by gripping the winder, using a tweezer hold the click away from the ratchet wheel and SLOWLY let the power down by allowing the winder to spin in a controlled manner.
3. Remove the pallets
4. Place the balance back in the watch and see if you can get a visual on the location of the roller jewel on the bottom of the balance assembly.
5. Use the #2 lever (the stud arm) adjustment to get that roller jewel dead centered in between the banking pins when at rest

PLEASE do not attempt this if you are unclear about any of these steps. I'd suggest trying this out on a junk movement first - although many watches do not have a movable stud arm (you set the beat by actually rotating the hairspring collet on the balance staff)

Best of luck!
 

[sstakoff]

By the way - are we certain the watch is not magnetized??????? Another very common cause of gain....

[Shoshone]

Thanks for the very useful information sstakoff !  I will incorporate this step going forward.

[ftwizard]

With reference to the Cousins issue. They are a wholesaler, but just continue as if you were a company and you can set up an account. You don't have the usual consumer protection though.