I have several bench supplies, but one that I am fond of is the Instek PSP-2010. As one might guess from the title, it’s a 0-20V, 0-10A 200W supply. It has a fan, but it stays off unless under heavy load.
Pros: solid build: metal chassis with carry handle. Output is quiet: the switching is well filtered. Very clean startup and shutdown: many low/moderate cost bench supplies have voltage spikes when you turn the output on or off; this one is clean, even with a significant inrush load current spike as shown below. The voltage setting and current limit are accurate and it has a CV, CC, and CW modes. The current display goes to 3 decimal places and while it claims to have only 5mA resolution, mine seems to have 2mA. The voltage display resolution is 10mV; mine reads about 60mV high at 6V (i.e. it’s pretty accurate).
Cons: although it has a keypad, you can’t directly enter voltages and currents, you have to use the encoder wheel. It’s not terrible, it has buttons to select fine and coarse adjustment so it’s easy to get to the setting you want, but a full 0..9 keypad would be a really nice addition. The other con is the use of a DB9 serial connector for PC connectivity. C’mon guys, it’s not 1995…USB please.
Repair: I use this daily and recently, when I went to turn the output on, the relay started to chatter and there was no output (i.e. it was failed). I was bummed and was getting ready to toss it, but as usual, eevblog came through. It turns out that there are two electrolytic capacitors in this supply (C25, C29) that commonly fail and when I opened mine up (6 screws and the cover lifts straight up), sure enough, those caps were bulging (see photo too right). I removed the board (4 corner screws plus a plastic locking standoff near the middle) and removed the caps; one measured 4.7uF, the other measured 14.6uF. I replaced them with Digikey P12389-ND, retaining the insulating standoffs from the old caps, and the supply works like a champ again!
