Inside the new Korad KA3305P linear PSU

[SantaClaw]

Yeah, well, I just did a voltage measurement whilst shorting it out.. 

It did 1.2v at 7 amps



I don't think there is any form of current limitation on it.

[stevelup]

The question really is what voltage yours outputs at 3A. Mine drops below 3V at just 1.9A load.

Any chance you can apply a load instead of shorting it out?

[SantaClaw]

I don't really have anything that can pull 3A, but I can tell you mine starts out low, at 4.918v

[Scottjd]

The question really is what voltage yours outputs at 3A. Mine drops below 3V at just 1.9A load.
Any chance you can apply a load instead of shorting it out?

Hi Steve,
I just ran a 3 amp load on mine. A short across a shunt in a multimeter will cause the voltage to drop and take all current over the rated 3A. Channel three doesn’t seem to have much in the over current protection.

Without load activated the voltage reads 4.9965 from the sense wires.
A constant current 3A load the voltage is 4.9464, I ran this for 4 minutes.
A constant wattage at 15 watts will drop the voltage to 4.935 with the amperage at 3.039
A constant voltage load with the CV at 4.94 will draw 3.004A, total of 14.84 watts
Basically, it looks like my channel three is stable at 14.80 watts, anything over and the voltage will dip below 4.9VDC
If I turned the load up to 3.45A the voltage drops will cut off.

Do you own a Koran unit?
How old is your unit?
Do you use channel 3 often?

[GuidoK]

I did a little test with my electronic load on channel 3 where I started the load at 2,5A and incremented the load with 0,1A every 4sec.
You can see that the current gets limited when it reaches 3,2A.
(at 3,1A the voltage is still dead on 5V and at 3,2A the voltage is dropped at well below 0,5V)

I have the rebranded RND unit from Distrelec

[aabbcc]

Power supply Tenma 72-2630 (Korad KA3303D ?) at a good price! 95.92€ + VAT

https://sk.farnell.com/tenma/72-2630/power-supply-bench-0-30v-5v/dp/2478798

Currently is the RND KA3305P also on sale at distrelec for € 144,-- ex VAT (probably only interesting for EU buyers)
So this is a rebranded version of the Korad KA3305P (so the programmable one, with normal screw/banana output terminals, not the safety ones)
https://www.distrelec.biz/en/bench-top-power-supply-number-of-outputs-voltage-max-30-current-max-programmable-rnd-lab-rnd-320-ka3305p/p/30061865
On this one the fan rotates slowly when no load is attached (so pretty quiet) and starts to run faster when load is applied. My model doesn't give any ratteling or such from the fan, just normal fan noise. I haven't opened it up yet to see what fan is inside.

Comes with version 6.0 and 6.2 from the software. But the software is a 240mb install or so. I think I'll try to get it working with sigrok, but I don't know if the dual channel Korad psu's are supported.

Hm I just bought this one used (albeit it's 3 years old) and unfortunately it has the rattling fan issue

Anyone found a solution to this?

[SantaClaw]

I'd change the fan? Find the specs on the fan's label and find a similar one on the net ?

[masterx81]

Little question: This psu have the series and anti parallel diode protection?
Thanks!