This is from my tektronix2430A that lays in pieces for 2months , and I haven't powered it up in ages, just busy, lazy and trying to learn a bunch of stuff along the way. And draw/map out the circuits on the PSU itself(with a marker, and on pictures)
I haven't powered it up to measure around in weeks.
U470A and B, of that LM358, how are they controlling Q465, Q479 in order to get the voltages written there.
The unregulated +8.63V on collector Q479 comes from the primary transformer. Where does its 8.73V base voltage come from? That would mean about say a Vce of 6.3V for Q465. And something a bit more than 9.4V on base of Q465, round it to 10V say. Then meaning 5V is dropped across R565, at 1mA, which splits into the base, and CR466.
Looking at the approximate or average U470A,B output voltages, and those diodes, practically no reverse current flows through CR465.
And some flows into CR466 into pin 7. And that fine tuning and feedback splits/controls the base current into base Q465 and then controls the base of Q479 ? Is that sort of what its doing, with the C485?
So fine tuning Vce of those transistors is what really makes the 8V ?
Also U470pin 3 is directly connected right back to the right side of C595, and so 1 resistor away from pin6
Here's the manual link, this is on page 410. The manual explains it on another level, on p131, I need to re-read as I learn more.
http://w140.com/2430-SM.pdfI've done some basic op-amp calculations, but not of the calculus type (but I've done lots of calculus)