I uncovered in my selection of old stock I got from an auction an automatic Seiko chronograph 6139. I read a little about some problems these watches had, namely the clutch on the centre chronograph wheel and the seconds hand mounting.
I am not sure if my diagnosis is close: while the chronograph is running the watch keeps time pretty well (within a couple of seconds per day worn on hand). Not always, but more often then not, when the chronograph is stopped the watch slowly stops (say it takes 3-4 seconds). When the chronograph is released the watch starts running. The fly back button does the job properly, start/stop/restart button works well. The watch had issues with the hammer click (was too strong - not original hammer spring) but for the time being it is ok.
I did not disassemble the watch yet as I am waiting for the original hammer spring. So this is a little hypothetical/frivolous question: Is there a chance that the (weak spot) centre chronograph wheel needs just cleaning and oil rather then complete replacement? Parts for this movement are scarce and the centre chronograph wheel is unreasonably pricey and the wheel itself - as far as I found out is not serviceable. Any comment will be appreciated.
Picture for movement ID.
Thank you for the answers!
The bottom one yes and appears clean, i have oiled properly it now. Not the top one because I would need to remove the balance wheel to unscrew from bottom, the regulator is not boot type, I am afraid I will never mount it again, it's too tiny piece for my skills.
All these tests are passing fine, in my opinion.
I made a round of cleaning in ultrasonic for balance wheel and bridge, trying to better oiling, I will see if any change tomorrow.
No shim originally found... I will eventually consider one or two hour wheel shim/spacers eventually, if that woudl still make a difference.
Thanks again! I'll try to make good use of your suggestions, this movement means a lot to me.
Have a Sternkreuz press i use for most glasses. Love it. I bought a second one on tradera some month ago for spares. Also have an other which looks like a Robur but not 100% sure it's a Robur. Was thinking i could make an adapter so i could use some other dies as the Robur ones cost a lot of money. Maybe i can part with that as i have to many presses anyway.