Seiko 7S26A - working but not working

[Waggy]

Good day,

I have a strange situation - I have restored a non-running Seiko 7S26A and thought I had done a great job

• Rate <5 s/d
• Amplitude >220 degrees
• Beat Error 0.1
• Hands move in sync
• Day/Date changes correctly

Then I notice that the second hand continues to make one revolution every 60 seconds BUT the hour and the minute hand barely move over the course of a day. I pull the crown and both hands move smoothly and correctly. Then once I push the stem back in again the second hand ticks correctly but hour and minute hands are VERY slow. Timegrapher still shows watch is working well.

Obviously the train of wheels/balance etc are working well as the watch seconds hand is ticking correctly, and the watch is performing well on the timegrapher. The hour and minute hands are installed correctly and not fowled as I can move them easily and in sync with the winding stem/crown.

So what could be stopping/slowing the minute and hour hands from moving correctly (min hand moved 5 mins in about 12 hours), but still allowing the seconds hand to move at the correct speed (60 seconds in 60 seconds) and the watch to perform well on the timegrapher and visual confirmation that the balance/escape wheel/pallet fork are moving well?

This has me baffled and I have taken the watch apart/cleaned and re-built with the same result... feel like I'm losing my mind as I don't see how these things can be happening at the same time! (pun intended)

[Cad101]

Hi Waggy

Sounds like you have a cannon pinion problem it may be loose or not seated properly.

[Waggy]

13 minutes ago, Cad101 said:

Hi Waggy

Sounds like you have a cannon pinion problem it may be loose or not seated properly.

Thanks, I'll take a look at it.

[mikepilk]

I agree with @Cad101, sounds like the cannon pinion is loose, or possibly loose hands.

How tight does it feel when you set the hands? Try pushing the hour and minute hands gently with some pegwood to see a) if they are loose, b) the hour hand isn't loose but the hour wheel turns 

[Cad101]

If its loose you can tighten it using a pair of blunted nail clippers. If you check the the pinion there will be a small dimple somewhere on the shaft this will need compressing a tiny teeny bit more it doesn't need much I usually put a piece of brass wire down the hole and give it a very small squeeze at the dimple then try it on the movement if all is good job done if its still loose give it a bit more but remember it doesn't take much pressure.

[Nucejoe]

3 hours ago, Cad101 said:

If its loose you can tighten it using a pair of blunted nail clippers. If you check the the pinion there will be a small dimple somewhere on the shaft this will need compressing a tiny teeny bit more it doesn't need much I usually put a piece of brass wire down the hole and give it a very small squeeze at the dimple then try it on the movement if all is good job done if its still loose give it a bit more but remember it doesn't take much pressure.

Hard earned experience Cad, I bet the canon pinion on your Zodiac 72 hasn't  loosened yet.

 

[Cad101]

1 minute ago, Nucejoe said:

Hard earned experience Cad, I bet the canon pinion on your Zodiac 72 hasn't  loosened yet.

 

Thats a blast from the past I still have that in my box still wear it too lovely watch.

[Waggy]

Thanks to all of you for your comments and support, you were correct. I removed the cannon pinion and noticed that there was some debris in there, after cleaning and re-applying some lubrication I can report that the watch is now running well.

[Cad101]

5 hours ago, Waggy said:

Thanks to all of you for your comments and support, you were correct. I removed the cannon pinion and noticed that there was some debris in there, after cleaning and re-applying some lubrication I can report that the watch is now running well.

Glad we could help thats why we all come here nice watch too