Hi everybody. Spent two days (literally) trying to reuse a power supply from a printer with no success. I took apart two large printers and have the same issue: 3.3v, 5v and 12V work fine but 24v does not output any current. It requires some kind of feedback or input of lower voltage (just like ATX power supply) but cannot figure out how. Tried just about any kind of loop-back with “flowing” or “static” current to no avail. At this point, it is not worth from the time perspective but it has become a challenge. I have attached pictures of the board itself and setup I was running trying to “fool” it into turning on the supply. I am relatively new to electronics and arduino and the goal is to build arduino powered CNC. Please help.
At this point I am not trying to “fool” the PSU to output the 24V but rather trying to figure out the PCB and modify it so that the output happens without any kind of feedback (is there a relay that is controlling the output?). This would also allow not to have a 5v supply running on a side all the time. The first picture is the entire set-up when trying to hack it. The rest of the pictures are the closeups of the PSU’s PCB. thank you again.