I have a Seiko 5 with a 7009 movement. when i initially received it, it had a pretty short reserve, definitely less than 24 hours. It kept time pretty well. For the past few days, it would run a little slow, losing about a minute an hour. Today I started wearing it at 7am, periodically looked checked the time and it was okay up until about 2pm. at 4pm, the watch was 5 minutes behind, at 4:45 the watch was alomst 20 minutes behind..
So i got home, opened the case, and found a service manual online with an exploded diagram. This was a cheap watch so I have no problem tearing it apart with the use of this manual. I was able to learn a lot more about mechanical movements (knew almost nothing other than winding would power the watch). I have one question about the balance wheel and balance spring.
My balance wheel has a little (what i believe is a) jewel located right around the center of the wheel, much like the black piece at the 9-10 oclock position in the picture below:
To my understanding, the jewel on the balance spring, hits the little two pronged fork on the pallet which in turn, pushes the escapement. as the balance wheel oscilates back, it hits the fork on the other side. This little contact initiates the escapement to turn a bit more at a faster angular velocity than the first time, which pushes the pallet, which gives a little shove to the already spinning balance wheel. this shove maintains the oscillating motion of the balance wheel.
Please correct me if I am wrong.
So now, I have my questions: what gives the balance wheel the initial "kick start"?
Can anybody diagnose the symptoms in the first paragraph?
Now for part 2: I opened the watch and began taking things off on the non-face side. This is how i came to my above conclusions of the operation of the watch. I used the following manual:
now on page 3, I turned the ratchet wheel screw (35) which is connected to the barrel with the main spring. I turned it clockwise and started to "manually" wind the watch. Of course, it did not unwind. thus my next question is what was holding the main spring from unwinding instantly? was it one of the jewels (entry/exit) pallets?
Also, I took out the balance cock, wheel, and spring. when i tried to put it back, I was unsure of whether or not the spring needed to be slightly wound (therefore providing a bit of tension). what is the orientation of the wheel when it is placed back in the movement? Should I let the wheel sit in its equilibrium state then put the balance cock on?
I know this was an incredibly long read but I am actually very excited to be learning about movements. If you're still reading, thank you for bearing with me and for your time.