Fast, slow, fast, slow

[Cyanide]

This is timegraph display from a used ETA 2737. I know it needs a clean/service, but what should I be looking for, to explain it running fast/slow/fast/slow? It looks like a regular cycle to me

thanks, Chris

[jdm]

Beside the amplitude that is kind of low, there is something increasing friction every 6 seconds. It points to a problem with the train or escape wheel in my opinion. You can find a timegrapher pattern reading guide somewhere in this forum or googling.

[clockboy]

I don,t think there is a ETA 2737 is so I can not find any info on this one. However if it is a auto then it could well be the mainspring slipping.

[StuartBaker104]

Most advice I have read says to "service it first" then diagnose. Your pre-service trace is a useful reference. If it's like that afterwards you know you didn't cause it and you can start your diagnostic with dirt and poor lubrication eliminated as a cause. If it's fixed afterwards then all is good and you may be happy to attribute the cause to something you saw along the way!

S

[Cyanide]

Thanks for your replies. I typed the number wrong, it's a 2780, and is an automatic. I'll give it a clean, and see what happens.

chris

[matabog]

clean and check the escape wheel pivots and spokes 

[clockboy]

Just check all parts as you strip the movement including the mainspring 

[jdm]

I stand corrected, the wave period is 12 ticks not seconds. I suspect something amiss with the escape wheel, not the mainspring. 

[Alastair]

I had something similar with an Accutron. You could see it speed up and slow about every second, and in total, run fast .

I thought the Index wheel was shot, but on removal I found a fibre bundled up around the pinion end of the arbour. A good clean and eviction of the fibre cured the problem. It wouldn't surprise me if you found the same thing on your escape pinion.

Edited August 15, 2016 by Alastair

[evn137BANNED]

Here you go....that roller coaster

Ed

[digginstony]

Looks like you may have a bent pivot on the escape wheel

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