🔴 Korad KA3305D Power Supply Repair - No.1292

Korad KA3305D Power Supply Repair

I MIGHT have damaged my Korad power supply which manually recharging cells in a battery pack... I heard a noise and smelt magic smoke.

I teardown the Korad KA3305D and fix the problem, and replace its feet which also seem to be falling apart.

Replacement Parts Used:

#TheDefpom
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[IanScottJohnston]

Quote "sometimes you need more than 1 power yes!, 5 to hand on my workbench, 2 Agilent's, 2 CSI's and an EEZ BB3 each with their own purpose LOL!

[yoeribolderdijk]

3:21 That spare cable is for the usb/com port module in Korad KA3305P model, i have two of those.
Great power supplies, did some mods tho.

[ElectronicsIdiot]

I've got a similar power supply. My one looks virtually identical inside, but has Tenma branding and recessed banana sockets. I'm not sure if your one has the same problem, but in my one the fan made a loud ticking noise. It turns out they were using PWM to control the fan at about 10 Hz. I ended up putting a 1000 uF capacitor in parallel to take the edges off. It sounds a lot better, but the transistor driving the fan gets a bit warm.

As for all the components on the control board, I think they've spun their own ADC and DAC. Not sure why they wouldn't use some off-the-shelf solution - I can't imagine it's cheaper to use all that PCB area and place a bunch of components rather than just throwing down a single chip. Perhaps it's an older design.

[craxd]

The idea of them was to blow a fuse, or trip a breaker, if the wrong polarity was presented. I would have thought that something would have opened up and killed the supply.

The number of them that I have replaced on mobile radios is astounding.

[andersvandegevel]

That's D15; D18 is in between the relays.
The 1kV rating will be so it can act as a snubber when there's an inductive load across the output.

[capriracer]

:20 That poor power supply is crying out for help. What have you been doing to that thing? 😂

[stevenbliss]

Piss poor reverse protection if the diode blows before the fuse!

[repairtech]

Get some JIS bits. You'll like them I'm sure. (Japan Industrial Standard)

[armandine]

I sense some anticipation about the new Siglent power supply - for some unknown reason that went over my head - are these supplies the new must have?

[QsTechService]

Nice easy fix what model power supply did you order? The same as everyone has ?

[ukaszsmoa]

What was that sound when you turned the psu on at 0:20?

[andymouse]

I wondered why your iron appeared to struggle with the wick and copper pours...290 ℃ ! that's conservative.