Expert: Martin Meyer - 4/18/2008

Question
QUESTION: I have an Emperor clock that I built back in 1982. It has been running flawlessly since then, at least until this Sunday (The day I always wind it). Since then it has refused to chime and only the center weight descends. The clock still keeps perfect time, it just won't chime.

At about 5:35 this afternoon, I manually moved the hand to 5:45 and it did chime, but it chimed 6:00, not 45 minutes past the hour. I believe that the movement is the 100-M moon dial movement.

Can you suggest some "typical" causes that I can check to see what the problem may be? Do you think that the movement can be repaired or would it be best to simply replace it with a new one? i understand that some of the early Emperor movements were suspect but this one has 25 years of service so I don't that its that.

Thank you for any suggestions you might have.


ANSWER: Hi Scott,
    There are many causes of chime failure. It could be due to need for lubrication, jamming of the chime hammers, or stalling in the gear train due to bearing wear. Please browse my previous answers for more detailed information on those topics.
    The average lifespan of these movements is about 20 years. Eventually the bearings wear, and the movement needs to be overhauled or replaced. Emperor used Jauch movements in their older clocks, then changed to Hermle movements. Hermle movements can be easily replaced, and that is preferable to having them overhauled. Jauch is no longer in business, but, in most cases, a Jauch movement can replaced with a Hermle movement. In this case, some other modifications are necessary, including changing one weight to a heavier one, replacing the hands, and using shims to mount the new movement at the correct height on the seatboard.
    It's true that the Jauch movements did not wear well, and a Hermle replacement is a much better movement.

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

QUESTION: Following your advice, I bought and installed a new in-the-box Hermle 451-050H (94cm) movement, which is the same as the original movement. Before installing it I did some minor lubrication to it using "clock oil".
The movement works fine with but one exception: It will not strike the last note in any of the 4 quarter hour sequences. It simply leaves the hammer in the air to fall as the first note in the next chime sequence.
I have attached a picture of what it looks like after a chime. While the wire on the raised hammer looks bent (as well it may be) it is positioned correctly to hit the chime bar. When the raised hammer shown is not the last note in the sequence, it is positioned the same as the other three.
I have added an arrow to indicate a gear held on by a set screw. This gear also has a black dot on it. Would removing and repositioning this gear help to correct the chime maladjustment?
What kind of adjustment would be required to make the last note sound?
Thanks for your help.

Answer
Hi again Scott,
    The large gear that you indicate is very slightly out of adjustment. It was possibly not set up correctly at the factory, although this is unusual. You can see that the base of the hammer wire is raised above the level of the other chime hammer assemblies. This is because the hammer tail is caught on one of the points of the pinwheel, when it should be released.
    Turn the minute hand to the first quarter and let the clock chime. The first quarter sequence strikes four notes in descending order, so you should be left with the front-most hammer raised as in your photo. Now, loosen the set screw on the large gear, but do not remove the gear. Hold your finger on one of the upper gears in the chime train to prevent the movement gears from turning. Then move the large gear counter-clockwise a very small amount, just until the raised hammer drops. Then retighten the set screw. It may take a couple of adjustment attempts to get the large gear in the correct position. You can prevent losing track of which hammer should drop last, by always making the adjustment on the first quarter, where you know that the sequence should be four descending notes, and the hammers falling in order from back to front.