My Surprisingly Fast 41CX

[akpoff]

In another thread I mentioned this 41CX shows signs of prior surgery, and now I know more.

This 41CX is fast, not 41CL fast, but probably LC-circuit-fiddling faster.

I initially noticed pressing keys would often show the key name briefly before executing the function, where my other 41CX would not. Yesterday I happened to XEQ BEEP and got the chipmunk version, which led me to comparing longer-running functions like FACT 40 against the other 41CX. It's noticeably quicker, nothing like a DM42, but quicker compared to stock.

The only thing left to do, then, was to figure out which approach they took. In message 3 of this thread Theo Kas mentions upgrading his calculator back in the day by replacing the 140pF capacitor with a 22pF cap. He also notes common values range from 22pF to 33pF.

A closer look at my circuit board shows a CM4ED 0220J0 capacitor where the 140pF capacitor normally sits, hidden below the piezo-electric buzzer.

   

Unlike some of the other options, mine isn't switchable. It's turbo all the time. I tested a card reader and wand with it. So far no ill effects. In fact, other than flashes of key names when I press keys too slowly, and chipmunk sound effects it works just fine.

Mystery solved. My little 41CX is full of surprises.

Edit: Correct Clonix with 41CL. See below.

Cheers,

--Aaron