Repair + Service: Junghans TopTimer / AS5008

IMG_7710It’s a Junghans, so chances are high that Torsten sent it in 😉

Junghans joined of course the Alarm watch craze, and came up with the TopTimer. This is the super high-end offering of alarm watches, with day, date, and an auto winder that winds both the movement and alarm mainsprings!IMG_7712

On top of that, there is a great little regulator on the balance, and the movement has 25 jewels. If you want an alarm movement, this is the one you want.IMG_7716

And this is the auto winder that takes care of winding both mainsprings. One direction it winds the movement mainspring, and in the other the alarm mainspring.IMG_7719

The dial has some damage at the centre, and that comes from people trying to lift off the alarm hand with a screwdriver. There is almost no clearance between dial and alarm hand, so it’s best removed by carefully lifting the dial off whilst the hand is still in place.IMG_7720

The bottom plate with the day and date discs.IMG_7721

The movement with the auto winder removed. On the left side is the alarm train, and on the right side the movement train.IMG_7726

The gear train is now visible.IMG_7730

The alarm train – the barrel that powers the alarm, the wheel that drives the hammer, and the hammer on the bottom right. Works pretty much like an escape wheel / pallet fork.IMG_7737

The day/date and alarm release on the bottom plate.IMG_8052

The AS5008 doesn’t suffer from a lack of parts 😉 It must have been quite expensive to produce.IMG_8056

Before putting anything else in, I will put the base movement back together and adjust it. The new mainspring is in the barrel, and the gear train is in.IMG_8058

A very well performing movement, especially considering how much stuff had to fit on that plate!IMG_8059

Now I can start on the alarm train.IMG_8366

When putting the keyless works together, I notice that one of the clutch wheels doesn’t freewheel properly, so I order a new one in.IMG_8369

Now I can put the rest of the movement back together. When putting the hands on, I notice that after I had the date to change at midnight, it changes as 1 a day later, and at 2 the next, and so on. There must be something slipping!IMG_8402

And here is the reason. The day/date change wheel has two teeth missing. The new wheel in the package. Luckily enough, spare parts for this movement are available without problems.IMG_8403

Finally, I can put the dial and hands back on. It’s not that easy putting the hands on, as the movement has an alarm and date. So I start off with the hour hand, and make sure that the date changes at midnight. Then I set the alarm to go off at 6, put the hour hand on 6, and remove it. Now I can put the alarm hand on, and the hour hand back onto the same position. Minute and second hand go on in the usual way.IMG_8405

The mother of all alarm watches!

8 thoughts on “Repair + Service: Junghans TopTimer / AS5008

  1. Nice one!
    If you want an automatic alarm watch with day and date I do not know other alternatives but the AS5008. The last mechanical alarm calibers to be developed back in the late 60s early 70s, and a very fine one indeed.
    Certina used it, so did Zodiac and several other smaller brands.
    They also did a AS5007 without the day (date only). Certina actually skipped the day window, but still used a AS5008 as basis for their version. Why? I guess we will never know.
    There are at least a couple of other “proper” automatic alarm movements out there not to be forgotten: The JLC caliber 917 and the Lemania/Omega caliber 2980/980. The Omega version (cal 980) was the only that had the option to set the alarm precise to the minute (the Memomatic).
    JLC still makes their fantastic MemoVox watches to this day.

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