Seiko 7006A Strange Timegrapher Trace, Escape Wheel Issue?

[steve1811uk]

Hi, I think that I have an issue with the escape wheel. The periodic noise shown on the Timegrapher has a period of 5 seconds, which I believe is the time it takes for the escape wheel to rotate once. The watch has been cleaned and lubricated and is a 21 jewel 7006A and is keeping good time. I'm going to have a look at the escape wheel for issues later. Does anyone know what might cause this so I know what to look out for? Thanks in advance, Steve.

[Nucejoe]

You have located the issue, bad escapewheel tooth?  

Personally can't see such faults unless under high magnifiction. I bet you inspect parts with an ordinary loup. 

[steve1811uk]

11 minutes ago, Nucejoe said:

You have located the issue, bad escapewheel tooth?  

Personally can't see such faults unless under high magnifiction. I bet you inspect parts with an ordinary loup. 

Hi, I am new to this hobby and I am finding it very interesting and satisfying bringing old watches back to working condition. I must admit that I didn't fully inspect the escape wheel before reassembly. I do have a x20 old binocular microscope that I can have a look with. To me it appears that the issue is happening on 6 out of the 15 escape wheel teeth all next to each other on one side. Does that suggest anything to look for?

[rodabod]

Just to be clear, on this particular timegrapher display, is it just the yellow dots which are sensed from the microphone - is the blue line a simulated centre?

[rodabod]

Considering the yellow trace alone, I think you have likely correctly diagnosed the issue, since it does appear to have a period of 5s. The escapement perhaps changes phase minutely early or late on a single tooth. So perhaps you could look under high magnification as suggested and compare teeth. 
 

If the effective instantaneous beat error (if you want to call it that) is as small as it looks, then in reality it may not noticeably affect the performance. 

[Nucejoe]

9 minutes ago, steve1811uk said:

Hi, I am new to this hobby and I am finding it very interesting and satisfying bringing old watches back to working condition. I must admit that I didn't fully inspect the escape wheel before reassembly. I do have a x20 old binocular microscope that I can have a look with. To me it appears that the issue is happening on 6 out of the 15 escape wheel teeth all next to each other on one side. Does that suggest anything to look for?

Ya shows six dots in row !  Perhaps on escape pinion rather than teeth.  If a wear on pinon, sometimes I can avoid the wear by moving the pinion up or down, which is to be done by moving the jewels or their housing. We just await reinspection.

[rodabod]

That’s a good point about the pinion leaves. If they don’t look pristine (especially on antique watches) then I sharpen a piece of peg wood and run it up and down between the leaves. If there is corrosion then I add a tiny amount of autosol, but it must be very carefully cleaned after to avoid contamination. 

[Nucejoe]

5 minutes ago, rodabod said:

That’s a good point about the pinion leaves. If they don’t look pristine (especially on antique watches) then I sharpen a piece of peg wood and run it up and down between the leaves. If there is corrosion then I add a tiny amount of autosol, but it must be very carefully cleaned after to avoid contamination. 

Autosol ! when it comes to horol ..material, I live in fourteen century, its new parts if I can,t get inventive.

[steve1811uk]

2 hours ago, rodabod said:

Just to be clear, on this particular timegrapher display, is it just the yellow dots which are sensed from the microphone - is the blue line a simulated centre?

Blue and yellow are tick and tock, not simulated.

[steve1811uk]

Thanks guys for the really good tips. Well I took it apart and gave the escape wheel a rub all over with a fibre glass brush then cleaned in the ultrasonic with lighter fluid. To be honest I couldn't see anything out of the ordinary. After reassembly the periodic noise has gone. Amplitude reading is lower now but the previous reading of 285 could well have been skewed by the noise I think. Amplitude is actually on the rise, 261 as I type.

[rodabod]

Well, for a Seiko I’d say that’s looking good!

[rodabod]

One thing worth mentioning:  be careful in general when using a “scratch brush” as they do as the name perhaps implies, leave scratches. The escape wheel tooth tips must ideally be perfectly smooth. However, they probably still are as escape wheels are usually tempered to “glass hard”. 

[steve1811uk]

41 minutes ago, rodabod said:

One thing worth mentioning:  be careful in general when using a “scratch brush” as they do as the name perhaps implies, leave scratches. The escape wheel tooth tips must ideally be perfectly smooth. However, they probably still are as escape wheels are usually tempered to “glass hard”. 

Thanks for all the tips guys. Loving my new timegrapher, funded in the main from the sale of an old Seiko quartz 5Y23-8A11 that had sat in a drawer for most of the last 28 years.