Fuck yeah!! The power supply that I've been working on since last week is all cleaned up and back in action 😁😁😁

Close-up (apologies for it being so grainy but my tablet's camera sucks..):

is that Switching PS?

@wowotek yep, a 500W (50V 10A) SMPS to be exact 🙂 I've dialed its trim potentiometer all the way to 55V though, as it'll be powering 2 DPS5005 lab bench power supplies. Those work best when fed something between 53 and 55 volts, so yeah.

This looks better. 👍

Looks way better! I'm still interested where the extra winding one the large choke is connected. It appears to be the output filter inductor, so last time my best guess was that they control the synchronous rectification with that. But as the TO247s are labeled ‘D’, it probably only has a passive rectifier.

@7400 I'll check for that on the supply later on, but my best guess would be current sensing? I mean, that wire is pretty thin after all.

@7400 I've looked at it earlier today, and my initial guess of it being a choke is wrong. Turns out that it's actually part of some pretty heavy filtering on the DC side. The tall capacitors near the (former) screw terminals are for voltage ripple reduction and the coil with the big windings is for reducing current spikes I guess. That'd make the (formerly all loosey-goosey) thin coil a good way to measure something about that big coil. Current, magnetic flux, something like that I guess. Not sure why that'd be better than using a current shunt though. Maybe it's more efficient than jamming 500W of power through a shunt.. but meh. Interesting design choice, that much is for sure. Also not sure if it's a good idea to make 2 coils share a core... Doesn't that make a transformer?

It is a transformer, yes. And as I thought, it's mainly the output filter choke. You didn't trace where exactly that extra winding is connected?

@7400 it's connected to a reverse-biased diode, into some capacitor, then some long trace, ... I didn't feel like tracing it all the way to the controller. It's certainly not going into there directly.

Meh, okay. It's a minor thing anyway.

@7400 Well, I just looked a little bit further and it looks like the diode and capacitor are there for half wave rectification and DC smoothing. That then goes directly into the controller (if only I looked a little bit further..) through a rather long trace. Probably high impedance so half wave shouldn't really matter. My best guess is that it's measuring the state of that coil by using the DC voltage from that other coil and its rectifier.

What controller does it use?

@7400 LD7575PN.. some kind of PWM controller apparently. It looks quite potent for its small DIP8 size actually!

Looks like they added a winding to the filter inductor and omitted the auxiliary winding on the main transformer. It's actually supplying the controller once the power supply has started up.