Casio CQ-1 Recreation Information

Until I tidy up the github repository, here's some snippets relating to the Casio CQ-1 recreation.

 The first PCB is really a prototype as well, it just fits in the case better than the first prototype. 

The dc-dc converter that is used on the prototype is this one:

https://www.ebay.co.uk/itm/401621208294

It's a variable converter and I worked out that about 23V is needed for the VFD, so I then put the module in component form on the PCB. This is the circuit:

The transistor in the ground side is to allow the processor to turn the supply (and hence display) on and off. The 49R resistor is to limit current.

The other dcdc converter on the prototype is not based on a module, it's a circuit I made up from the datasheet and put on a PCB. 

On the PB that fits in the CQ-1 these converters are both in component form.

I'll add more information here now and again as I tidy up the repository.

There's an error on the PCB: One of the ON signals should have come from VBAT and came from another signal instead, which meant the PCB didn't turn on after I had populated it. Once fixed it was fine, but it does mean a tricky mod is needed, which has to be done with surface mount components.