Citizen eco-drive divers 200m(BN0000-04h, 7878A) twitch

[zoulzubazz]

https://parts.citizenwatchservice.co.uk/order/BN0000-04H

I recently got this watch and is roughtly 22 years old. it was not working at all when I got it(meaning second hand was not moving). Took is to a high-street watch repair shop and three weeks later it was returned to me saying the parts on this are obsolete and cannot be found, but this time it was ticking every two seconds or so (this I understand is a typical sign of low battery/capacitor). I figured the calbre was a citizen eco-drive 7878 from the markings on the back and ordered a 295-56 (https://www.watchbattery.co.uk/cgi-bin/fcpm.pl?words=7878a&wt=ew&bl=an&d=/products/BBCU-CIT56.shtml) battery/capacitor for it. This I took to another watch repair shop and asked them to install it for me, which they did and it was working fine and keeping good time as far as I could tell (the batteries were compatible because I checked the one he'd got out). But now it has started stopping abruptly and the second hand goes into a bit of a twitch moving forward and backward in the same position (not two second ticks). When given a tap the watch starts ticking like normal again only to go into a twitch a few hours later. What could be the issue? Is it worth getting serviced or should I give up on it altogether?

[Kalanag]

23 hours ago, zoulzubazz said:

…But now it has started stopping abruptly and the second hand goes into a bit of a twitch moving forward and backward in the same position (not two second ticks). When given a tap the watch starts ticking like normal again only to go into a twitch a few hours later. What could be the issue? Is it worth getting serviced or should I give up on it altogether?

The root cause for this behavior might be dirt or old oil in the movement which increases the friction in the gear train and therefore the power demand from the stepper and the battery/capacitor. If so a service would solve the issue. Whether it is worth the effort or not can not be answered in general.

Edited October 8, 2022 by Kalanag