A7750 running too fast per hour

[Netbis71]

I have a PAM with 7750 sec.@9 no chrono. When watch arrived on first day it was running +1 sec/day. Next day for overnight, I put the watch on the winder, in the morning it was +23 sec.

Now it constantly runs about +2-3 sec. per hour, so I stopped to see a watchsmith and on timegrapher it was 0.0 sec when watch was laying flat, and +1 when at 90deg sideways. He told me do nothing looks good for now wait and see.

This is so weird I cant understand why, I found one post here that it could be main spring, or reversing wheel issue (not sure what that is), but why timegrapher results were this good;

Rate: 0.0 sec/d (flat) (+1s/d when turned on one side)
Amp: 313 (very good)
Beat Error 0.7ms (ok)
Angle 52

I just checked again, and it gained 6 seconds in 3 hours, or 2 seconds per hour. Looks like acceleration is not linear and it stays accurate then maybe accelerates randomly over time, otherwise how timegrapher could show good reading?

I have other watch with 7750 (PAM087h) this one can be all day all night on the winder or not, and it is dead on +3~4 sec/day at most.

Any clues?

Tx.

 

[Netbis71]

Over a month no comment?
Its hard to believe no one had experienced this.


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[Netbis71]

Any clues ?

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[Rx4Time]

Is it a positional variation? Face up is usually the fastest position. Try face up for two or three hours then face down for the same and see if there is a significant variance between the two.

 

[Netbis71]

Flat on timegrapher was showing 0 sec. On the side +1 last time i checked. It gains a lot when fully winded on winder or when i wear it. Movement test results were good during QC and at watchsmith. It almost feels like a main spring has irregular power. Laying flat in my box keeps ok time.




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[Rx4Time]

Flat on timegrapher was showing 0 sec. On the side +1 last time i checked. It gains a lot when fully winded on winder or when i wear it. Movement test results were good during QC and at watchsmith. It almost feels like a main spring has irregular power. Laying flat in my box keeps ok time.




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I've got a PO out now for a regulation and the watchsmith was having a similar issue, but it was running over 200 sec/day fast in face up position. Turned out the hairspring was misshaped. He has it now running +6 sec per day. I"m waiting it's return as he is also waterproofing it and had to order a replacement gasket.

 

[Netbis71]

Thanks for the info, mine is not so bad, but still it is fast 3 sec per hour. I'm going to slow it down a bit and will see what happens.

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