Jump to content

Inlaw's quartz clock issue

Recommended Posts

I have my inlaw's quartz chiming clock to "repair" the issue is that the clock is losing time, I have heard that quartz clock movements have a life of 5 -10 yrs and as this clock is over 10 yrs old probably the obvious thing to do is replace the movement, but I can't source a chiming pendulum movement with a battery on the correct side for the cutout in the metal back of the clock case, the original movement is a Hermle 1237, I'm not keen to cut or modify the back of the clock case I've so I'm looking at possible "repair".

My initial thoughts were that the battery contacts were intermittent - the battery contacts are sandwiched between the movement main plastic housing and the copper side of the circuit board, so I soldered short lengths of wire directly to the circuit board battery contacts from the battery housing terminals, the movement was however still losing time.
There is a trimmer capacitor on the board, the crystal is a 4.194304mhz unit so a divide by 2, 22 times would give the required 1 sec timing pulse to the movement motor, I checked the crystal with my scope and the period was around 238.4 nS which is close to 4.194304mhz, I have adjusted the capacitor and so far the movement seems to be keeping good time using my mob phone as a reference, there is a few minutes of backlash in the gears so when the minute hand is at the 3 position it will show slightly fast and at the 9 it will show slightly slow, if I can get the movement to gain no more than 15 or so seconds a week I'll be happy, by the time daylight saving changeover arrives it will only be a few minutes out.

This brings me to my question - why have a trimmer capacitor at all, surely if the crystal is running at the design frequency then it would not need to be trimmed, am I expecting too much from the crystal?

Share this post

Link to post
Share on other sites

Cousins sell them also I have used this company a few times https://www.clockparts.co.uk/index.html#menu

Whilst on quartz clocks I was asked to look at a Westminster quartz pendulum clock because it had always chimed incorrectly ie 10mins past the quarters & 5mins before the hour. Solution removed the battery moved the hands (using the adjusting knob) to 05:50 inserted the battery again and moved to the correct time again using the adjusting knob and now it is spot on.  


Share this post

Link to post
Share on other sites

Hi  with any electro mechanical device like a clock, especially a quartz clock where the gears are formed by injection moulding, here is always going to be some variation , hence the trimmer on the electronics to compensate. Hermle movements along with Seiko, Herchinger and Junghans are pretty good movements the cheaper ones are as manufactured and the discrepencies are compensated using component values.  Newgeneration clocks are a good source.

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing

    No registered users viewing this page.

  • Topics

  • Posts

    • Which model is it? When was it last serviced?   Accutrons are backwards of mechanical watches, in that you have the power source turning the escape wheel, which then powers the train up through the hands. In a mechanical watch there is an increase in speed and a reduction of torque from each gearing to the next, so there is almost no power on the escape wheel. In an Accutron the tiny power and movement of each vibration of the tuning fork is increased by 7 or 8 fold at each gear set, so that at the hour and minute hands there is tremendous power. The instantaneous date system on a 218 model will shake your wrist! And it would stop or hinder a regular mechanical watch.   The upside is a well adjusted Accutron is very reliable and runs for years and years, the downside is that they will run long after the lubrication had dried and grind the pivots to dust. I suspect the friction between the driving wheel and canon pinion has become weak, and the canon pinion and hour wheel are sticky, so the watch runs but doesn't move the hands. As the seconds pinion is before this intersection it continues to move, and the hand setting works since that is another gearing that drives the canon pinion directly.   As it does run, it should just need a service. But the longer it runs in this state the more potential damage that can be done.
    • About an hour and a half, but I have some helpful stuff like a toolmaker's microscope to get the position of the steady pins, screw, and point where it should sit between two teeth, a CAD program I can import an image of an original jumper, trace,  and then scale a traced drawing to size, and a little CNC machine that cuts out the part. The spring section still starts at around 0.15mm and gets thinned by hand to about 0.04 or 0.05, that's where the fun is.
    • I understand this seems to be a common problem related to the canon. Does anyone have any advice or a link to a manual or diagram that can explain how to fix this?   the watch gums fine and when setting it the hour and minute hands move correctly. 
    • Has anyone got user manual of CASIOTRON 79CS-51. I bought the watch some 30 years ago. It,s named Casio Universal calender.
  • Create New...