3 output PSU.

Sometimes it happens that the power supplies of some machines need to be replaced. And sometimes I can't find the ones that suit my needs in stores or on specialized sites. So I developed my personal version.

I added some extra features that are not usually found and that can be very useful. Troubleshooting a few Drumulators and other SP12s proved this to me. 

It had been a long time since I decided to create this type of PSU. But between the initial idea and the realization of the concept, it can sometimes pass some time.

This PSU should be able to deliver 2A on each output. This is what I will have to check when the prototype will be made :

The uPF--2.

The Wichit Sirichote Z80 MICROPROCESSOR KIT clone : The uPF--2.

I worked on replacing the Wichit kit with an FPGA version. During this work, I said to myself that the keyboard had to be replaced. On one hand because I think that it is impossible to work under good conditions with the original micro-switches, and on the other hand, the multiplexing has not been correctly implemented and can present big problems in the event of simultaneous pressing of several keys. No protection diode and no phantom key suppression as been placed : 

The Wichit Sirichote original design.

Furthermore, I decided to recreate the keyboard as a separate part. This will allow me to develop the processor board independently. However, I also decided not to use a parallel link because it is not practical at all. I preferred to connect the keyboard with a simple serial cable to the processor board.

There are not many solutions for the choice of keys if you want something 'pro'. So I chose the Cherry type keys. For now, I have only studied the keyboard circuit. Here's what it should look like :

To be continued...