Balance wheel will not swing without assistance

[Deggsie]

Hello all. I have recently cleaned and serviced an AS2390 movement, which initially after lubricating/ reassembling would begin to tick with just a turn or so of the winding stem. However, a week on and the movement has developed a problem. If the movement is not wound daily and mainspring is allowed to completely de-power, then during winding the watch will not begin tick without a slight ‘swing’ to assist it. In fact it is possible to wind the mainspring to maximum and the watch will only start to tick if a slight swing is applied. Thereafter the watch keeps good time and does not ever seem to stop until the spring completely de-powers again.
 
I am curious as to what is causing this, since initially the watch would start ticking with one or so winds of the crown. Your thoughts and help would be much appreciated please.
 
Kind regards
 
 
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[Nucejoe]

Check if impulse jewel is in beat.

Release barrel power at the ratchet click, then check the ballance, it should come to stop/ rest where impulse is inside the fork horns. 

How to test , the impulse is in beat if the slight clock/anticlock move of ballance wheel causes the fork move.

 

[MrRoundel]

As was mentioned above, it sounds like the watch slipped out of beat. Perhaps this is because the hairspring collet fits too loosely on the staff?  It's always nice to have a watch in beat so that it takes off when you wind it, without having to give it a twist. Good luck.

 

[Nucejoe]

Yes , good point by MrRoundel, if the collets fit on staff is loose, the ballance- HS is liable to slip out of beat eventually. 

[Watchtime]

some experienced knowledge guys, thanks for sharing...learning a lot

[Deggsie]

Thank you all for your invaluable input. I will check the approximate beat this evening by putting the balance assembly onto a spare main plate and checking to see that balance comes to rest with the jewel at mid span between the banking pins. I know this will be mk1 calibrated eyeball only, but should give me a reasonable indication as to how well in beat the watch is or isn’t.

One other factor has crossed my mind.. I think this may have started after I applied lubrication to the pallet stones. Might I have overlubed and caused too much viscous drag for self startup? I used moebius 8000 and none on the pallet pivot

Kind regards


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[watchweasol]

Hi Deggsie  you may have hit the nail on the head, To be sure powerdown the watch remove balance and fork. Re-fit balance only and check where the imnpulse jewel rests  should be dead centre of the banking pins if not all the advise given applies  cheers

[Deggsie]

Many thanks watchweasol. Still at my workplace just now so can’t check but promise to feedback my findings to you all. Cheers Deggsie

 

Ps. Is moebius 8000 ok on the pallet stones? What is the best method to apply it? Thanks

[Nucejoe]

16 minutes ago, Deggsie said:

Thank you all for your invaluable input. I will check the approximate beat this evening by putting the balance assembly onto a spare main plate and checking to see that balance comes to rest with the jewel at mid span between the banking pins. I know this will be mk1 calibrated eyeball only, but should give me a reasonable indication as to how well in beat the watch is or isn’t.

One other factor has crossed my mind.. I think this may have started after I applied lubrication to the pallet stones. Might I have overlubed and caused too much viscous drag for self startup? I used moebius 8000 and none on the pallet pivot

Kind regards


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Very modest of you, you service Rolex so I think you know all this, some fresh oil have surely got on escapewheel teeth from overlubed pallets, so if you just rinse the fork in your lighter fluid, some of that fresh oil deposited on the wheel will get back on pallets as the fork gets reinstalled. 

Surely you know the impulse jewel is in the right position to receive energy when in beat, that dosn,t ,however,  mean energy made available there to be received is neccessarily at max, the fork will get energized at pallet end  by escapewheel, so if pallets get dispositioned during cleaning, trouble, real trouble, I am very experienced with loosing pallets as I tried to adjust them.

 

[Deggsie]

Very modest of you, you service Rolex so I think you know all this, some fresh oil have surely got on escapewheel teeth from overlubed pallets, so if you just rinse the fork in your lighter fluid, some of that fresh oil deposited on the wheel will get back on pallets as the fork gets reinstalled. 
Surely you know the impulse jewel is in the right position to receive energy when in beat, that dosn,t ,however,  mean energy made available there to be received is neccessarily at max, the fork will get energized at pallet end  by escapewheel, so if pallets get dispositioned during cleaning, trouble, real trouble, I am very experienced with loosing pallets as I tried to adjust them.
 

Hello Nucejoe. Sorry you mistake me for an expert Horologist as I do not service Rolex (perhaps in the future if I keep practicing). I appreciate your contribution though [emoji846]

What I will add is that I have now taken out the pallet fork and escape wheel, cleaned in naphtha, rinsed in ipa and reassembled. The balance now energises after a few turns on the crown. So, luckily I think the pallet stones are still correctly located.

Regards


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[Nucejoe]

3 hours ago, Deggsie said:

Hello Nucejoe. Sorry you mistake me for an expert Horologist as I do not service Rolex (perhaps in the future if I keep practicing). I appreciate your contribution though

What I will add is that I have now taken out the pallet fork and escape wheel, cleaned in naphtha, rinsed in ipa and reassembled. The balance now energises after a few turns on the crown. So, luckily I think the pallet stones are still correctly located.

Regards


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Hi, Glad to hear this,  excessive lube was your own diagosis too,  the solutions you used are new names to me, I search online to read about them. Thanks for sharring.

Oh my friend here   celebrates success.  Best wishes joe