I had a damaged coil in my Oakley Timebomb as well as a bad capacitor, so I took it upon myself to tear it down and repair it. Hopefully this guide will help you resurrect a watch you might have sitting around that Oakley can’t/won’t repair. The movement/caliber that is in a Timebomb is a Seiko 5M42. The Seiko 5M42 is a kinetic style caliber that uses an oscillating weight to recharge a capacitor. The capacitor is the old term/part, the replacement cell is a Lithium rechargeable battery, Seiko # 3023-5MZ. This energy is used to power a quartz circuit to run your watch. This caliber was used in a bunch of Seiko watches and you can use those to help repair your watch. I bought a couple of broken/damaged Seikos off of the ‘bay so I could get replacement parts and have a couple of movements to practice on. The pair I bought was $20 from “thewatchcollector” (no affiliation, but highly regarded on the watch forums) in the Philippines. Not a bad price for replacement parts at all. One watch still had a perfect caliber/movement inside of it that when I tested it out with the new capacitor, it fired right up. You could also replace the whole movement if you had a capacitor leak and corrode your watch. Brand new replacement calibers are available online for around $100. I’ll cover this as well.
Before you begin, Google search for the Seiko 5M42A Parts Catalog/Technical Guide for the parts breakdown and oiling points. Here are some of the tools that I used in my repair of my damaged Timebomb. Most of these I picked up off of Amazon. I also had a couple of small magnets handy for finding errant screws and parts.
1. Screwdrivers 2. Band Pin Tool 3. India Hand Remover 4. Homemade Dial Protector (sandwich bag) 5. Workmat 6. Case Knife 7. Toothpick 8. Moebius Watch Oil and Oiler Needle 9. Rodico (handy for picking up small parts/residue free cleaning) 10. Case Holder 11. Hand Press 12. Movement Holder 13. Tweezers metal and plastic 14. Hammer and Band Pin Punch.
Having something to store and separate all the parts comes in really handy!
This is one of the best things you can get to help with working with all these really tiny parts!
**Standard Disclaimer: I am not liable for any damage you cause or trouble you run into.**
Pop one side of the clasp off so you can get to the back of your Timebomb and tighten into your watch holder. Remove the four screws with a PH000 Phillips screwdriver and lift off the back cover and the gasket. Here you can see the Seiko 5M42 caliber that is the heart of your watch. That half-moon weight you see with Inertial Generator printed on it, is the kinetic oscillating weight that drives the generator that recharges the capacitor. Use a 1.5mm screwdriver to remove the screw that retains the weight and remove. Under that is the oscillating weight wheel that drives the generator. It lifts right off and you can now get to the old capacitor.
You can also see the coil that HQ damaged when they had my watch. Remove the two capacitor screws with a 1.0mm screwdriver. Lift the capacitor cover off and pull off the insulator. Set those two aside as the new rechargeable battery comes with different replacement bits. Study how the two tabs of the capacitor fits into the mainplate before you remove it so you can get it placed back in the exact same spot. The straight tab fits into a small slot in the mainplate and the side with the hole presses down on top of the gold capacitor connector. Use a non-conductive tool here so you do not short out the capacitor. If all your watch needs is the capacitor replaced, please skip ahead to the reassembly. If your watch needs something else replaced, please follow along.
Now take out both circuit block cover screws and lift the circuit block cover off. Watch your screwdriver so it doesn’t slip off of the screw and destroy a coil like the HQ “repairman” did. These little coils are fragile.
Underneath the cover is the circuit block. It lifts off with no connections.
Now you can remove the two oscillating weight bridge screws and carefully lift out the bridge straight up off of its posts and wheels.
Under the oscillating bridge are the intermediate wheel and the generating rotor which are supported by the two pinkish/purple jewels you see in the bridge. That oscillating weight wheel that is under the rotating weight meshes with the intermediate wheel which drives the generating rotor that recharges the capacitor. You can now lift out the intermediate wheel, generating coil, the generating rotor and stator. The rotor will probably stay inside the stator, but be careful that it doesn’t fall out. No big deal if it does, just don’t let it get away from you. Then remove the last screw for the other coil block and lift it out as well. To test the coils, use an ohm meter. The spec on the generating coil is 280Ω - 380Ω and the coil block is 1.7KΩ – 2.1KΩ.
Now the rest is not for the faint-of-heart. If you really want or need to go farther to replace damaged parts or if the caliber is dirty proceed. These photos are from my practice watch. I’d recommend using a ruined watch to do this the first time. Study how everything works together and take pictures/notes. Remove the train wheel bridge screw and carefully lift off the train bridge.
Under the bridge are five gears and all of the setting levers.
Lift off the + capacitor connection and inspect for damage or corrosion. The train wheel setting lever lifts off its plastic post easily. Caution as the next bits could be under spring power and you don’t want them flying away. Slide the switch lever off its plastic post and away from the yoke post, remove. The setting lever and yoke now will lift right off their posts. In order to be able to remove all the gears, the seconds hand must be removed. Remove all of the wheels/gears, the step rotor and the rotor stator and clean as needed. That is as far as you can go on the back of the caliber.
Reassembly of wheels and setting levers.
These steps can take some finesse. I had to do it a couple of times to get everything right… Slip the rotor stator back into place and insert the step rotor, sliding its axle back into its hole. Slip the third, fifth and minute wheels back into their respective holes/jewels. Slide the fourth wheel back through the caliber to help hold all of the wheels together. Place the clutch wheel back into its slot and slide the setting wheel back over its post.
Diagram taken from Seiko Manual.
Place the yoke back in, ensuring that it engages the clutch wheel in its slot and the spring arm side of it is snug against the main plate. Slip the setting lever on its post with the dog leg headed downward and nestled into the cam slot on the yoke. Place the switch lever over both pieces, engaging both its post and catching the leg of the spring against the yoke post. Then place the train wheel setting lever on its post over rotor stator and make sure the long tip of the yoke engages the outer slot. After all of that, don’t forget the capacitor connection. Place the train wheel bridge over everything making sure that all of the wheels are inside their holes and not bound up. Tighten the two screws incrementally while checking that nothing is bound up. Whew….hard part is done.
Put all of the coils and the circuit back in the reverse order.
TIPS: Make sure the generating rotor and intermediate wheel are not bound when you install the weight bridge. Make sure the oscillating weight wheel engages the intermediate wheel when you slip it back over its bearing. Oil as you go along in accordance with the manual. Replacement gasket is 29mm if needed.