Jump to content

"Timegrapher" sensor for LED/LCD watches

grenert
 Share

Recommended Posts

grenert Member

grenert

Posted
Posted

Hi, all.

Testers for digital quartz watches (Seiko QT-77, QT-99) have a sensor to pick up the internal quartz oscillations and determine the frequency. How do these work? I know that conventional analog watches use piezo or other microphones, but I would think these wouldn't work for a watch without any moving parts.  Anyone know or have circuits/service schematics that show the design?

Thanks!

 

Link to comment
Share on other sites
JohnR725 Distinguished Member

JohnR725

Posted
Posted

Some use what they call capacitive pickup. If you look at the witschi timing machines they'll claim inductive/capacitive usually on one pad and then they have a piezo On the other side.

13 hours ago, grenert said:

Anyone know or have circuits/service schematics that show the design?

Try doing a patent search you'll find some of the early electronic ones. Not the best way to build him though I heckuva lot of integrated circuits.

Then they give you an idea about sensors here's an image out of a manual for a witschi machine. The acoustical is a protruding metal pin that goes down to a piezo Pick up. Then the capacity of not clear what that is because it's hidden from view and then on the other side there were coils if I remember right interfere right cup course. I haven't taken one of these apart but  the past I had the taken apart my witschi  earlier version can't remember the model number and unfortunately I don't have any digital pictures. They used to act up and I'd have taken apart and see if I try to fix it which is able to do which is quite interesting considering they sand off all the part numbers. They really don't want you to know what's inside the machine. Which is silly because if you're a professional design engineer reverse engineering they make devices to read integrated circuits and tell you what they are or you just dropped the schematic and figured out for yourself. To just makes it a pain in the ass for someone trying to troubleshoot and repair the thing.

 

pickups for quartz watches.JPG

Link to comment
Share on other sites
praezis Super WRT Addict

praezis

Posted
Posted (edited)

I just answered how 32 kHz quartz pickup works per question. Today however this is less important as inhibition comes into play. So the picked up quartz signal is changed in the dividing stage and does no more show the resulting rate.

The inductive pickup catches the motor pulses (1/sec or less) which do show the rate.

The capacitive pickup catches the display frequency of digital watches and also the 4.19 MHz quartz frequency formerly used in clocks.

Frank

Edited by praezis
Link to comment
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.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  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.

×
 Share
Go to topic listing


  • Recently Browsing

    • No registered users viewing this page.

  • Topics

  • Posts

    • Endeavor
      New balance staff not riveting to balance

      By Endeavor · Posted

      Picking up this side-tracked post again as I just removed a balance staff of a 1920's Omega (35,5L-T1) I was impressed by the way @Delgetti had his setup when he had to change out a balance-staff (https://www.watchrepairtalk.com/topic/28854-new-balance-staff-not-riveting-to-balance/page/2/#comment-244054 Not only that, but also the idea of removing the seat first before punching the staff out from the seat-side, avoiding the whole discussion of the rivet yes/no enlarging the hole. I didn't have the fancy clamps & tools Delgetti has, so I used my screw-head polishing tool. Initially I used #1500 grit diamond paste on the steel wheel, which kinda worked, but very slow. I changed to #800 grit diamond, which worked better, but still slow. Then I glued #240 sanding paper to the steel disk; That worked and with the disk hand-driven. Once close to the balance wheel, I took the sanding paper off and continued with #800 diamond paste. One can only do this when the balance wheel sits true on the staff and it has no "wobble". I went on grinding until I saw some diamond paste on the rim of the balance wheel. This was as far as I could grind and it seemed that there wasn't much left of the seat. Carefully, with my staking set, I knocked the staff out. Turns out that the thickness of the seat left, now a small ring, was only 0.1mm. The balance wheel hole is in perfect shape and no damage done to the wheel at all. Of course, if the wheel has a "wobble" or isn't seated true on the balance staff, you can't get as close and there will be more left of the seat. In my case, it worked perfect 🙂 Very happy how this worked for me 😊  
    • ManSkirtBrew
      Accutron 218 transistors

      By ManSkirtBrew · Posted

      As is tradition, one step forward, two steps back. Got the board populated and soldered into place without any issues.   But no hum. So I started testing the coils with an ohmmeter. I got 5.84k ohms across D1 (from red to red in the picture below), which is as expected. But I'm getting an open circuit for the other drive coil and feedback coil, D2 and F1 (from green to each of the two yellows).   Since the movement was working with my breadboard setup, it implies I somehow broke the connection between the coils and the solder lugs. They're all the way at the bottom of the lugs, but maybe the heat migrated down and broke the connections? I guess it's possible it happened while cleaning the flux off, but I used a soft artist's brush and isopropyl alcohol. I did a lot of high magnification examination, and I don't see any issues, but let me know if you see anything I missed or if you can think of anything else I should check.
    • GuyMontag
      Watch of Today

      By GuyMontag · Posted

      1947 NOS Ambassador 'C'. Actually, the case came without the movement so the movement isn't NOS, but she sure is pretty.
    • watchweasol
      AS2063 - hand setting

      By watchweasol · Posted

      Hi attached is the AS 20XX. Service sheet although there is no 2063 mentioned it may be of some use to you AS_AS 2060,1,2,6,4,6.pdf
    • JohnR725
      Epilame / Fixodrop

      By JohnR725 · Posted

      one of the problems we have is visible versus invisible. For instance millennium disulfide another high pressure lubricant black in color. I was told by somebody worked for the Boeing company that they had a piston like device somewhere that has eight call it around it to grab it so it has to slide and in the collet has to grab. But if somebody puts that type of dry grease on where grease with that in it it embeds itself basically in the metal and they have to throw the whole part away they get use it all. So I suspect on all the dry powdery lubricants that they will go into all the basically microscopic cracks and crannies of the metaland that's where it is visually at least until you scrub it off your visually going to see it which is good because you want your lubrication the stay word is. But I'm sure it doesn't last forever on the metal it's just a really nice lubrication  
×
×
  • Create New...