My Decimus has lost its Ooomph !
  • Looking for some help here.

    After running faultlessly and accurately for over a year, for the past month my Decimus has been giving trouble. Initially, it began to lose time, which was not corrected by adjusting the pendulum weight. I then noticed that the escapement was "missing" occasionally, which explained the loss of time. Upon further investigation, I noticed that the amplitude of the pendulum was rather less than it had been previously. I was used to the bob swinging to the edge of the clock base, and now it is barely 2/3 of the way there, not quite enough to advance the mechanism, hence the escapement missing occasionally.

    I have also noticed that the clock no longer "self starts"; the pendulum merely trembles when the power is switched on. The gap between the pendulum magnet and the base is correct and the swing alignment seems to be right. I am wondering if the electronics are getting tired, and if there is any way of checking this ?

    Is there something else which I need to be attending to ?

  • I had exactly the same problem with my Quintus. The clock would stop and pendulum magnet would wobble slightly when switched on and off. The cure i found was to spray all moving parts with wd40 silicone oil (other oils are available) I can only assume that friction was the cause.
  • Hi George

    Good to hear from you again.

    I must admit I hadn't considered friction this time, since the Decimus pendulum balances on a knife edge (almost literally). But I suppose friction in the rest of the mechanism could be dragging it back.

    I am reluctant to spray WD-40 around, but I do have a can of dry lubricant which is a possibility. I also have some graphite powder which I could paint on the bearing surfaces.

    Can I assume that we are discounting an electronic problem, then?

  • Hi Paul

    Its not actally WD40 but a silicone based lube under the name. It wont attract dust as mineral oils would and can actually spray the whole frame, nooks and crannies without any discoloration and dries without any residue to see.
    When first had problem i bought another pulse mechanism fron Dave and didnt seem to have much effect so i would try lube first, dry lube may be better than dirty graphite which tends to get everywhere.
    Let us all know how you go on.

  • Hi George

    The silicone lube you have sounds like my dry lube. I'll give it a go.

  • The Decimus will swing even when the mechanism has so much friction that it will not turn, as opposed to the Quintus the Decimus pendulum action is completely divorced from the gear train, a small amount of energy will be absorbed when the escapement wheel advances but hardly worth mentioning. When the mechanism/escapement starts skipping, then as you correctly wrote it is a lack of amplitude.

    As the Decimus was working fine before it can really only be a lack of "oomph" from the drive, as you also correctly surmised.
    However I would be surprised if it was the drive, what power source are you using and have you tried replacing ?
    If the problem persist with a new power supply then it can only be the drive.

    The Quintus pendulum directly drives the gear train, too much friction equals small amplitude, so your cure for the Quintus was correct George (thanks for that), but does not really apply to the Decimus.
  • It is mains driven via USB.
    I will order a new cable.
    Can I assume that the drive unit is OK?
  • If it is the power source that is defect it is most likely the adapter rather than the cable, so replace that.
    It is, as so often, a question of elimination, if you change the adapter and the Decimus works as it should, then problem solved, if it does not help then it is most probably the drive.
    That the drive should be defect is improbable but by no means impossible.
  • Been trying something out. Hence the silence for a few days. I turned the whole thing a few degrees on its vertical axis, and the pendulum swung better, and the clock has kept perfect tine for several days now. The pendulim no longer swings parallel with the wood grain on the clock base, but it does pass exactly over the indicator mark on the base where the electronics are.
    This is not how it was when I made it, but it's working.