Casio CQ-1 LAP Button

[blackjetrock]

I've been having a wander around the PCBs of Casio's CQ-1 and would like someone with a CQ-1 to try something for me. It looks to me like the LAP and '=' keys are actually the same key electrically. It looks like they have the same scan and sense lines on the keypad PCB. can someone with a working CQ-1 (if such a thing exists, I have 3 and all are non-functional, otherwise I'd try this) see if the LAP key can be used as '=' when running the calculator, and '=' can be used as LAP when in stopwatch mode?

Thanks

Andrew

[Maximilian Hohmann]

Hello!

(08-01-2020 08:05 AM)blackjetrock Wrote:  ... can someone with a working CQ-1 (if such a thing exists, I have 3 and all are non-functional, otherwise I'd try this)

Really? I have three as well and they all work. You need all three batteries (the single AA and the two AG13 coin cells) in place for it to work, even if you only use the calculator. Who knows why...
On one of my units the small extra lid over the coin cells is missing. Without it the cells don't get pressed against the contacts firmly enough to make contact. I had to insert a piece of thick cardboard to make it work.

(08-01-2020 08:05 AM)blackjetrock Wrote:  It looks to me like the LAP and '=' keys are actually the same key electrically.

I can confirm that, either of the two keys performs both functions.

Good luck in reviving your calcualtor!
Max

[blackjetrock]

Ah, it's interesting and makes sense that the two keys are the same, my code gave the same scan code which confused me for a while.
All three of my CQ-1s have different symptoms, so I have decided not to fix them, and instead recreate the functionality on a new PCB. Well, if I can get it all to fit into the case...

Regards

Andrew

[blackjetrock]

Well, I have sort of fixed my CQ-1, I just have to finish the code, and sort out some wrinkles.

https://trochilidae.blogspot.com/2020/09...-cq-1.html

Andrew