Prusa Black PSU Not Fuctioning
I purchased a MK4S kit a few years ago, recently upgraded to Core One. while I had my MK4S, I tried to power it on but it didn't work. After contacting Prusa through live support, I determined it was the PSU. After opening the PSU, on the bottom of the board, I found that one of the components had exploded. After having it sitting around in my closet for a few months, I thought I would try to fix it.
I took off D45 (RED) thinking there might be some information on what type of diode it is (That is what I think this component is). After soldering it off and finding nothing under it, I tested it with a multi meter in the diode testing position and it read near 0. I also tested D46 (YELLOW) and it came out at the same reading. I thought that maybe it wasn't a diode since there was no reading both ways. I also tested D35 (BLUE) and it did come out with a reading. The labeling on the board says that it is a diode, because D stands for diode and other things that say what they are, have the first letter next to a number ( numbers go from 1 and up).
I am pretty good at most tech stuff, but I don't know a ton about circuits and what not, so I'm wondering if anyone out there knows how to determine what type of diode this is so I could order some and replace D45 and D46 since they both have no reading. I have tried searching for a schematic but have had no luck. I emailed Prusa and Delta PSUs to see if they have any info for me, but no replies yet.
RE: Prusa Black PSU Not Fuctioning
I am all for repairing instead of replacing, but I draw the line at switching power supplies. The circuit is a large feedback loop which controls the output voltage; a visibly damaged part is typically just the symptom of an underlying failure elsewhere, or/and will have taken down other parts with it when it failed. As you have experienced, finding the right spare parts (which are not only functional, but also safe to use) will be difficult without a schematic.
Neither Prusa nor Delta will give you repair information, I bet. They can't, for liability reasons: An incorrect homebrew repair may pose a safety risk, both during repair and during subsequent use. Please do yourself a favor and buy a new power supply.
Nice touch by Delta to let the design engineers put their names on the PCB, by the way! 😎