Changing the capacitor

Changing the Capacitor / Rechargeable Battery

Seiko Kinetics are well made watches but there are a few common problems you need to look out for.

  • Faulty seals on the case back and crown
  • Leaking battery
  • Stuck casing screws
  • Rust

Note: Rechargeable batteries have a low internal resistance and can be damaged by shorting out so take care when manipulating them with metal tweezers.

So let’s start

Here is the watch which we think the battery is faulty. It is a 5M42 movement which is one of the most common kinetic movements that you will encounter. It has a battery tester incorporated into it making it easy to check the state of the battery.

The Movement comes out of the front of watch but in this case the screws on the front are stuck. Drop a bit of oil on each of the screws and allow it to soak in.

Now the screws come out with no risk of them breaking in the casing.

Lift off the bezel and below it is the button to release the stem. in the Run position gently press this button while pulling the crown and it should come out easily. If not then the stem maybe rusted into the casing and may need replacing.

As you can see the stem is quite rusty but not enough that it needs replacing but the seal on the crown needs changing and any specks of rust loose in the casing need cleaning.

Lift the movement out and place it in a movement holder.

Unscrew the weight screw and lift off the weight and the wheel.

Unscrew the 2 screws holding the battery bridge and remove the insulator and the battery. 
Note: on all Seiko movements never press down too hard when screwing/unscrewing screws otherwise you will have problems

Look for battery acid on the contact marked with the red circle

If you see anything like this then you really should be doing a clean and service on the watch. The insides of the battery will get between the teeth of the wheels potentially damaging them and coat the circuit board. If you just change the battery then it and the watch may come back faulty. Do the job correctly otherwise you may loose the customer.

This is the old battery which is one of the original capacitor types.

Reassembly is as easy as removal but take care not to short the battery (it has a very low internal resistance and can be damaged) or touch it with your fingers (it never looks good seeing fingerprints)

Refitting the Rechargeable Battery (Sorry Seiko: Capacitor)

Here is the new battery we are going to fit to this watch

On the left is the new battery insulator and bridge and the old ones on the right. It is important to change them as a set.

Place battery in the movement without shorting it. Make sure there is a good contact to the circuit board.

Fit the insulator taking care that the locating pins fit through the holes in the insulator.

Fit bridge and screw it down. Take car not to press too hard on the screws.
I add a drop of oil to the ball bearing and the other 2 jewels. I am not sure if this is the correct thing to do but I feel it is a good idea as these parts are put under a lot of stress by normal use.

Fit the wheel and bridge and screw it down well.

Clean the case thoroughly before you reassemble.

Refit the movement. Add silicone grease to the button seal.

Fit a new seal as the watch will not be opened for many years

Screw the front bezel on to the watch and the job is done. A dab of silicone grease on the screw thread will stop it binding to the casing making it easier to remove in the future. I usually pressure test these watches but this is up to you and your customer.

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