We’ve covered these CNC 3020’s in the past. They are physically solid machines but the electronics offer some room for improvement. [Peter] is certainly no novice at working on these machines. He’s already fixed a failed power supply and he’s back at the upgrades, again focused on the power supply. This time he’s replacing the transformer-based one with a couple switching power supplies.
The stepper controllers and spindle speed circuit need both 48 and 24 VDC. [Peter] purchased two separate power supplies, one for each voltage required. Before installing the new supplies, the stock one had to be removed, along with the transformer. Even with the old parts removed, there was still not enough room for both new supplies to be installed inside the stock case. [Peter] decided that mounting them to the top of the case would be appropriate.
This current setup has been in use for several months now. [Peter] reports that it has been working well and does not get hot even during long-running programs. If you are interested in [Peter's] previous power supply repair or his PWM spindle speed control, check this out.