The very first thing everybody does after passing ham technician exam of course (sarcasm)

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I have a dual variable DC power supply (actually triple if you count the 5V tap)
I really want to fix this thing.
It is supposed to go from 0-30V DC on left side (slave) and on right side (master)

The left side will hit about 13V and then drop to ten or eleven.

However when in parallel mode both sides will hit and hold 30V

There is a schematic for the digital meter version but (to me) is not helping much.

It has relays which I suspected and obtained the correct replacement relays but I would just be shotgunning parts replacing.

It's all through hole analog transistors resistors capacitors and stuff

This has been on my list but I put it off until my ham exam so I could practice test and that's done now so time to get on with it.

Ive been in it before and one disadvantage is the boards have to be unplugged to get to anything.

As usual I'm trying to learn so id rather trip and fall in the dark and discover something rather than be told exactly what to do so appreciate any "hmm yeah ya might wanna go look over there"

One thing I already learned here is watch out for any low voltage capacitors so that's on the list

Also I know this is the test area but this is kinda OT but if anyone is interested I appreciate it.

Hope you all are having a great weekend

 

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Just to show the level of PITA-ness

I was glad to see a bunch of those little caps but unfortunately they are not low voltage

But the one that is bigger is lower than that

Oh well should be fun

No pain no gain

 

[doffo]

Congratulations on passing the ham exam! (Realizes I got my ticket in 2001. Yikes!)

Something that happened with an Astron power supply I had, you can set the amperage and voltage via the knobs in the front.... The issue I had the voltage was jumping everywhere! Long story short, the potentiometer was shot and even after cleaning it up, it behaved erratically. I ended up taking it out and shorting the two wires going to it. Held a stable voltage after that. (You can set the overall voltage on the potentiometer on the actual board inside which I got it close to 13.8v.)
Unsure if that is the case here, but when it sets to 10v, does rotating the knob quickly back and forth make any changes on the voltage readout?

 

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Thanks sir nice to hear from you I appreciate it I'm loading up to go cut some grass I will definitely check that out

 

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Well I finally got back on this
I'm kinda ashamed I didn't trouble shoot I just started replacing stuff

I had bought these relays man idk probably three years ago

Anyhow after playing with a capacitor I got enough courage to swap one out

As of now it works but I'm not so proud just guessing and all

Before it would get to about 15V and stall out then fall back to about 13V if ya left it like that you could hear intermittent relay clicks

So now if ya go full range ya get three relay clicks going up and going back down

Btw happy Fourth of July guys

 

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I was gonna mention something crazy about this. The past few years I had had my own come to Jesus with myself swearing I would make a serious attempt to fix it.
Not really knowing much I would say well at least get your multimeter and start measuring stuff like emitters and base etc voltage across resistors and capacitors and so on
Well everytime I started I would get these wildly fluctuating then decaying readings literally felt like I was in the Bermuda triangle. I figured my battery was low so I would grab another meter and the same thing would happen
I mentioned it to a very helpful mentor at another forum and he said it looks like a lab supply so it's "isolated"
So idk maybe I could have just stuck something in a socket for neutral or ground that is not part of the device and tried to do it that way idk