ETI magazine Feb 1979 - power supply (ETI-142)

[(*steve*)]

I just checked the control voltage. With respect to the +40V rail it seems to produce a nice even voltage which rises as power demand from the power supply increases.

With respect to other rails it has the same 100Hz artifacts.

The funny thing is, that because the +40V rail has ripple, I'd expect to see ripple on the control voltage to counteract it -- and I'm not seeing that at all.

 

[(*steve*)]

Yesterday I made a quick and dirty feedback circuit using an optocoupler, a zener and a few resistors. It made the per supply oscillate, so that's not a good thing.

I also trimmed up the voltmeter so it reads a little more accurately.

However I discovered that the ripple detection (for the overload indicator) doesn't seem to work at all. Also, lots of the components have been replaced. I think that replacing the op amps and the small signal transistors may not be a bad thing to do. One of the three terminal regulators was replaced...

Because of the way this is wired up, it's a real pig to get at the board. Since the parts are all cheap, and there's not that many of them, it may be simplest to just replace them all at once.

Also, I think I must be missing the last page of the article because the setup stuff doesn't get past the basics.

Oh, the ESR of the main capacitor bank on the switch mode regulator reads as lower than I can measure.