Witchi Wicometre 20T timing machine

[AlanB]

Hi!

I have one of these which has been gathering dust at the back of a cupboard for years and I recently pulled it out and though I'd sort it out because it would be handy in bringing repaired watches to time.  Witschi no longer have any documentation for these, but the circuit is pretty straightforward although the electronic construction is "unconventional".   

There are two boards, one with a 15840Hz quartz crystal and a three divider chain - two old style two transistor high ratio dividers with delay and a simple bistable /2. This divides down to 60Hz, 66Hz or 72Hz using chains like /11 /12 and divide /2 (for normal 18000vph) trains. This is amplified and drives through two power devices a synchronous motor which has a roller with a helix and a second simple geared motor train that moves the paper.

The second board has an audio amp plus output transformer which can drive a speaker (for hearing the action) or a schmitt trigger type circuit which drives a solenoid which brings down a bar over the paper for more conventional timing. However, I'm at a loss how the paper is marked. There doesn't seem to be an ink roller (like in a Greiner). So I'm wondering if anyone has ever seen a manual for one of these ?  Happy to scan my hand drawn schematics if they help anyone repair one. There is a second pulse integrator circuit which starts the recording motor after the solenoid has registered a number of marks in a given time period, which I guess saves paper.

[Faults were an open circuit input capacitor, bad connection to microphone and a bad preset potentiometer in the schmitt trigger (open circuit) all easily rectified]

 

Alan

[Michael1962]

Welcome to the forum Alan.

You should duck over and say hi in the Introductions area. The other guys will really appreciate that.

As far as your Witschi goes, you lost me in your second paragraph. I can spell electricity, but that is about it.

[jdm]

9 hours ago, AlanB said:

Hi!

FYI, we have a dedicated section where it's considered polite for new members to introduce themselves first. 

[LittleWatchShop]

It uses pressure sensitive paper most likely.

[LittleWatchShop]

13 hours ago, AlanB said:

Happy to scan my hand drawn schematics if they help anyone repair one.

I do not have one, however, it would be a service to others for you to provide the schematics as part of the historical record for some troubleshooting down the road. Other forum members have done this. There are a number of EE members.

[watchweasol]

Pictures of the mechanism and the machine would be useful to members.  some of these machines used an ink roller but not all  so ther is the passibility its using one of two systems. Not having had my hands on one of these machines but used to the different types of cashtill printers used in conjunction with the till, the systens they used differed from ink impregnated ribbons/rollers to heat sensative paper and also impact sensative,  so it could be any one of these systems. Hence the need for pictures and as LWS said the drawings will be gratefully recieved by other members of the forum who have a machine of this type 

[AlanB]

Hi,

Sorry for a slow reply - had a few unexpected medical issues. Here are the hand drawn schematics!  Hope there are no errors, but reverse engineered drawings sometimes do have the odd blip. 

Will take some photos and go and find the new introductions area!

Alan

 

 

CCF_000033.pdf

[LittleWatchShop]

Nice work.

[AlanB]

Here's a picture of the printing mechanism. At top of the helical drum driven by synchronous motor; above is the solenoid driven recording link (I have removed a cover to make function clearer). The two resistors are dropper resistors to run the large motor centre bottom which drives the paper feed roller (bottom left).  Despite all the circuits working no marks are made on paper - so I suspect maybe I need special paper!

[praezis]

Did you ask Witschi already?

Frank

[LittleWatchShop]

You need pressure sensitive paper most likely.  Similar to what the non-inked Vibrografs use.

[AlanB]

I tried asking Witschi - they sent me a nice manual for a machine with an LCD screen and told me all others were obsolete!

 

Pressure sensitive paper may be the answer. This paper is very old in a "Southern Watch and clock" package.  I didn't know that some Vibrographs used pressure sensitive paper. That's very helpful!