Korad KA3005D

[cponcsak]

So I got sick of spending way too much time researching which power supply would give me the least trouble and settled on a Korad KA3005D. I wont lie though. The deciding factor was that it was available on Amazon Prime and withing budget.

I don't really know a whole lot when it comes to power supplies but I thought I'd throw up some pics of the insides and scope pics. Everything look good to me. No bodged in wires or components. Everything was clean and the wires tied out of the way. Included brand name caps too. The overshoot when enabling the output is minimal. I've included pics for 5, 12 and 24v overshoots. The only issue I've seen with it is that it can spike the output when being powered off. Voltages range from a few volts to up to 20 at times. This only occurs when the unit is switched off. Turning off the ouput produces no spikes and shows a gradual discharge. It's a compromise that I can live with. The rest functions as you would expect. I couldn't find any faults with the front panel or controls. The fan can be a little on the loud side but the speed is controlled by the output current so its tolerable if you using low power circuits.

Sorry if the photos are a little blurry. Hard to make sure the focus is good on a phone. I can take better pics if anyone wants them.

[MK14]

The only issue I've seen with it is that it can spike the output when being powered off. Voltages range from a few volts to up to 20 at times. This only occurs when the unit is switched off. Turning off the ouput produces no spikes and shows a gradual discharge. It's a compromise that I can live with.

I can't seem to find much info on it. It would be interesting to see a photo of the front panel (sorry if you have, and I missed it), and maybe a spec sheet or something ?

The output overshooting (on switch off), can easily blow (especially sensitive and/or low voltage) stuff up. If it was me, I would strongly dislike that, and I would want to avoid using the power supply. (It would be all too easy to FORGET to switch the output off BEFORE powering down).

Maybe there is a quick/easy circuit modification, to eliminate or minimize the overshoot ?

I can understand the "pain", of choosing which power supply to buy. There are so many compromises to be made.

[pmaggi]

I think he is talking about KA3005D...

[MK14]

I think he is talking about KA3005D...

Thanks for the update. I'd never heard of it. There seem to be one or more similar types (like that one), from China (and maybe other places). Which seem to have the same basic design, but completely different names.

Like some of the ultra cheap multimeters, which look identical, but come with a huge range of different brand names.

https://www.eevblog.com/forum/testgear/220v-lab-power-supply-on-110v-mains-korad-ka3005d/

[cponcsak]

Whoopsies. You are correct. It was 4am when I posted that and I have corrected the title. The other thread you linked to said that the caps were fake. Is there any definitive way of identifying fake caps?

Like you said, many compromises. I think this one should do me fine until I can pick up a Rigol or something similar. Old test gear is almost impossible to come by in my area and shipping things like that off eBay costs an arm and a leg. I don't do anything low voltage or sensitive and 99% of the things I do use have on board regulators that could handle the voltage if I inadvertently hit it with the line noise when powering it off. It's primary purpose is to prevent me having to look for power adapters or battery packs and I think it should be ok for that.

I would also be interested if anyone has any ideas on removing the noise from the line when its powered off.

[MK14]

Whoopsies. You are correct. It was 4am when I posted that and I have corrected the title. The other thread you linked to said that the caps were fake. Is there any definitive way of identifying fake caps?

Like you said, many compromises. I think this one should do me fine until I can pick up a Rigol or something similar. Old test gear is almost impossible to come by in my area and shipping things like that off eBay costs an arm and a leg. I don't do anything low voltage or sensitive and 99% of the things I do use have on board regulators that could handle the voltage if I inadvertently hit it with the line noise when powering it off. It's primary purpose is to prevent me having to look for power adapters or battery packs and I think it should be ok for that.

I would also be interested if anyone has any ideas on removing the noise from the line when its powered off.

An easy mistake to make. I am very, rare in that I never, ever make any m1shtraks,

A picture is worth a thousand words, your capacitors look a tiny bit like these...
(Please see bottom of post, if picture missing).


I think the first step to improving/reducing the switch off line noise, is to try and obtain schematics for your power supply. Or someone may have reverse engineered the circuit somewhere on the net, for you. Then it is much easier to work out, how to fix that glitch.

But I'm glad that your current usage is little affected, by that glitch/bug.

Somehow, buying bench power supplies is much more exciting than many other things.
E.g. Small solder fumes bench boxes.

I know which I would prefer to research buying. Clue: It does NOT make  whirring sounds when you switch it on, and does not have a large black (carbon replaceable) foam pad in it.