PSU HiFi Amp

[m-Kresol]

You can ignore my request. It's not working yet, but I got a professional to look at the schematic and he confirmed it's good as is. Wasn't sure if he would reply to my email, so I posted it here too. thanks anyways.


I'm not quite sure where to put this, as it's neither Etcher's paradise nor a madbean project, but one of my own.

So, I was hoping to get a second set of eyes on my schematic for the PSU for my HiFi amp. I tested it yesterday and I the rectifiers work. The heater side is ok. But the high voltage side, which is supposed to give 285V DC only gave 40V at first, the second try only gave 10V, and now I'm down to below 1V. The transformer works correctly, I have 250V AC at the input to the PSU and 360V DC at R1, but after R1 the voltage breaks down. Also the primary fuse blew one time, which is weird because I thought the secondary fuse would go first as no heater current is flowing anywhere (wires disconnected/floating). I should mention that I measured every component before soldering and suppliers are trustworthy.

I checked all components, reflowed everything and desoldered C5 and C6 as I suspected those (I had to desolder C5 before which is a pita because of it's size and feared that I overheated it). with only C5 or only C6 the result is the same. Only very little DC voltage after R1. I also checked the datasheets for pinout of the transistors.

I'm suspecting something might be wrong with my schematic to begin with. I'm not entirely sure about the voltage stabilisation parts. The Zener diodes bring the voltage down to 285V and open the MOSFET, which should give also a little below 285V at the output, which is stabilized by C8.

I'm appealing to the electronics gurus (Brian, Jon,...) to have a look, I'd appreciate it. Thanks