LTC1799 PCB MODULE Casio SA-1

[Mikemodual]

Hi,
I'm new to this forum and a novis circuit bender so I hope someone can help me out with this question. I have purchased a LTC1799 PCB MODULE and looking to install it on my Casio Sa-1. I would like to keep the original timing crystal as an option with a switch in between the two. Could someone help me to explain how to go about this.

All the best, Mike

[Circuitbenders]

There is a general guide on the site at https://www.circuitbenders.co.uk/tutorials/LTCinstallation1.html

I've never done it on a SA1, but assuming it has a crystal or a resonator the principles should be the same.

[Mikemodual]

Thanks! I´ll give it a go! Fingers crossed:)

[daneelolivaw]

Hi Mike!

Usually what I do (and I did it on a sa-1) is to wire a dpdt switch in order to use both clocks. The central pin (is pin the right name?) of the switch goes to the IC on the Casio, the other two ends to the ltc1799 and the original crystal. Now, I can't exactly remember if the xtal in the sa-1 was a three legs or a two legs one. Usually only one pin is the one ne where to connect the incoming clock signal.
The other pole of the switch I use it in order to power on the ltc1799 at the same time I switch to its clock,in order not to drain batteries too quickly. Which the Casio sa-1, when I switch between the two clocks, it crashes. So, you either start it with the internal crystal or the Lyceum oscillator on. With other keyboards usually you need to power them on with the original xtal and then switch to the one you installed. Anyway, this is my experience..

Hope this helps mate, it's quite here...

Best

Sam

[Mikemodual]

Thanks Sam! It worked like a charm! I decided to go with a 3MHZ crystal with three legs (same as the SA-1 22MHZ) and wire them to a DPDT switch:)