It is currently 22 Nov 2017, 03:38


Casio cfx-40

Owners of VINTAGE DSM and LCD watches post their topics over here
  • Author
  • Message
Offline
User avatar

767Geoff

Wizard

Wizard

  • Posts: 499
  • Joined: 05 Feb 2007, 17:58
  • Location: VANCOUVER, B.C.

Casio cfx-40

Post14 May 2017, 23:48

Hello, new project:

Paid 200 for this working watch. Needed a new battery and looked like a new keyboard overlay. There is an after market overlay which looks excellent so I thought, give it a try.

Well it does work but the lower right button is intermittent. It does select and sometimes it locks the display. Tweeking or fiddling gets it to work again but only for a short while. The watch will lock up even when not touched, again fiddling with this button releases the lock.

So I disassembled the watch:

Image

Cleaned all components including button PCA interface.

Image

Assembled and tested, same problem. It is not a physical button interface problem. In fact, slightly pressing the PCA at the lower right button (not pressing the button) causes the lower right button functions to enable. Obviously a short somewhere.

So tracing backwards I see that this component is attached to the circuit of the lower right button:

Side view:

Image

Top down view:

Image

So what is it, and what is a substitute part number. It is a coil with two soldered connections and a can protecting it. It is in the lower right button circuit. It seems to be the cause of the intermittent function of the button.

On another note:

The keypad was almost unreadable and I expected it to suffer the delamination and decomposition so familiar with these, but, cleaning it in preparation for a new after market overlay seemed to resolve the unreadability issue. It does suffer from hairline cracking but is still intact and fully functional:

Before:

Image

After cleaning:

Image

Following photos are closeup of some of the components:

Image

Image

Image
Offline
User avatar

767Geoff

Wizard

Wizard

  • Posts: 499
  • Joined: 05 Feb 2007, 17:58
  • Location: VANCOUVER, B.C.

Re: Casio cfx-40

Post15 May 2017, 01:39

Okay, definitely the can. It looks like the surrounding shield was shorting to the PCA. I lifted the can just a tiny bit and the module now functions.

However the alarm function is very soft. The can does hav a trace coming from it to the alarm spring location so it is also involved in the button press sound.

So the question is, what is the part number and where can I find one??? Maybe other Casio databanks have similar part?

More investigation required.
Offline
User avatar

767Geoff

Wizard

Wizard

  • Posts: 499
  • Joined: 05 Feb 2007, 17:58
  • Location: VANCOUVER, B.C.

Re: Casio cfx-40

Post22 May 2017, 18:54

Got an aftermarket overlay that I can read. Epoxied the crystal in place. Working on getting a substitute can. Turns out this piece amplifies the alarm and is involved in switching displays through the bottom right button. I have the switch cycling working now but at the sacrifice of a aloud alarm. Once I have a spare working piece I will try to repair the one in place.

Beautiful function set for the sciences including logic testing. Easy to use. Always wondered though, why Casio could not have done both this model and the 20/200 series in stainless. They have such innovative designs and functions guaranteed to last 5 years!

It would be a simple thing to revive the science watches as they have the expensive part worked out, the shell. It would simply be a matter of keypad overlay printing and programming their version of the PIC processor.

Not a great shot, will take some later but here it is fully functional with the new aftermarket overlay:

Image

Return to Vintage DSM and LCD Watches

Who is online

Users browsing this forum: No registered users and 1 guest