Expert: Kenneth Saunders - 5/26/2008

Question
QUESTION: Hello,

I searched the AllExperts forum, but didn't find a solution to the curious problem I have.

The antique Junghans pendulum clock (I guess it's what you call a "Vienna wall clock") I recently bought strikes once a minute before the hour, and the rest of the strikes correctly on the hour. So at 11:59 it strikes once, and at 12:00 it strikes eleven times. What could be the problem? At half past it strikes once, correctly (although a minute early, but I don't mind).

Another question: the clock has two winding holes, and beneath each spring casing is what I assume is an adjustment screw. I understand one of them adjusts the speed of the clock, but what does the other one do?

Your help would be greatly appreciated.  

Best wishes,

Miro

ANSWER: the striking is due to an internal gearing problem requiring a pro to adjust- I can't explain it so you can fix it without doing damage to you or the clock.
  Adjustment screws beneath spring barrels are NOT adjustment screws! -- they hold the movement and dial in place in the clock case.

    The nut below the round swinging disk on the pendulum regulates the speed - raising the disk speeds the clock up by tightening the nut.

---------- FOLLOW-UP ----------

QUESTION: Hi, thank you for your quick reply.

I took a closer look at the gears, and noticed that if I manually lift the lever near the face plate, the clock will strike perfectly. Is that what you expected?

When I let the clock strike by itself, the hammer moves like this:

11:29 hammer hits down
11:30 the hammer rises up
11:59 hammer hits down.
12:00 hammer rises up and hits down X-1 times, and finally rises up.

If I make it strike by lifting the lever manually, the hammer will rise back up immediately after each hit, which I think is correct? It seems that the lever rises slightly one minute before the clock is supposed to strike and that causes the hammer to strike, but the lever stays raised which prevents the hammer from rising back up. So the problem is the part that is supposed to lift the lever every half hour?

An unrelated question: the previous owner has done something to the dial that has caused it to become very dark (here is a poor quality image of it, compare color of dial and the pendulum: http://riemun.huuto.net/auctionimages/6/9f/0b2bb2bf022ab992f65cc94f07671-orig.jp ) Is there some safe method for trying to clean the dial? The dial feels like plastic, it's probably laminated paper or celluloid.  

Answer
I took a closer look at the gears, and noticed that if I manually lift the lever near the face plate, the clock will strike perfectly. Is that what you expected? YES


So the problem is the part that is supposed to lift the lever every half hour? HALF & HOUR BOTH - again a tricky gearing adjustment-needs a professional.




Is there some safe method for trying to clean the dial? The dial feels like plastic, it's probably laminated paper or celluloid.
DO NOT TOUCH THE DIAL- leave as is! It is  a plastic coated paper that has darkened with age-enjoy that!