[G0HZU_JMR]

That looks to be the same PSU that I built back in the late 1980s. The circuit and project details were given in an amateur radio mag. The good news is that I found that the PSU was very rugged and worked well. I still have it although it doesn't get used anymore.

There are a few niggles with the design. If you turn off the PSU at the mains and then decide to turn it back on again a few seconds later then this will almost certainly blow the mains input fuse. This is because the soft start protection takes a while to drop out after turning off the PSU. So I would advise you buy a pack of 10 input fuses as it is very easy to blow the input fuse like this when setting up and first testing out the various protection modes the PSU has.

I put the current limit control on the outside of the chassis allowing the current limit to be adjusted from about 3A to 'a lot'.

When the PSU hits the current limit it will trip out the mains input relay so the PSU will turn itself off. This therefore isn't the same as a classic current limit on a big bench PSU. It does mean you have to make sure you set the current limit high enough to prevent your PSU turning itself off on SSB speech peaks when using it to power a 100W transmitter. In reality, I never had a problem with this because I turned up the limit to >25A when using it with a 100W SSB radio. I've also used this PSU many times with the current limit set to flat out when needing to start a car with a flat battery. The PSU always survives this abuse and it always starts the car!

Note that the main controller PCB has exposed mains AC voltage on it and also the mains input wiring is more complicated than on a classic power supply. This means there's lots of places to get a shock from inside the chassis. I do think the controller PCB needs a perspex screen over the mains connections and care must be taken to insulate all the mains input wiring including all the soft start wiring.