Dc power supply blow up! (QW-MS3010D)

[Oroshi]

Hello guys.
I have this power supply one week..
Yesterday when i short the leads to change the amps i hear a weird noise like something is going to crack.
And today when i press the power button i see smoke and thunders from inside this power supply.
I open it and i see a blown IRF 840 Mosfet, but it damage the board also.

[stj]

Re: Dc power supply blow up! (QW-MS3010D)

Yesterday when i short the leads to change the amps

??
why short the leads?

[Oroshi]

Re: Dc power supply blow up! (QW-MS3010D)

Because it's not programmable power supply.
I wanted 5v and 2 amp limit, so the way that works I short the leads with low voltage and adjust the current.

[budm]

Re: Dc power supply blow up! (QW-MS3010D)

https://cdn.badcaps-static.com/pdfs/...082f56a5ac.pdf
What was the Output Voltage setting at when you shorted the leads together to set the CC?

[Oroshi]

Re: Dc power supply blow up! (QW-MS3010D)

1 volt

[budm]

Re: Dc power supply blow up! (QW-MS3010D)

Well, it looks like the over current protection was not working so well.

[Oroshi]

Re: Dc power supply blow up! (QW-MS3010D)

What can i expect from Chinese cheap psu (70$)?
Ι already order new IRF840 mosfets to replace all of them. I know it's time wasting but i give it a shot.
I don't have much experience in electronics to find what is the problem and fix it. I don't find any schematic for that psu.

[R_J]

Re: Dc power supply blow up! (QW-MS3010D)

It looks to me like the heatsink shorted out the circuit traces? I found this for a MS-605D but I think it is close.

[petehall347]

Re: Dc power supply blow up! (QW-MS3010D)

poor insulation technique

[Oroshi]

Re: Dc power supply blow up! (QW-MS3010D)

Just terrible. R_J I think the same. Also I found more like lifted pads and poor soldering work.

[Oroshi]

Re: Dc power supply blow up! (QW-MS3010D)

Anyways it's not worth the time. Thanks guys.

[PeteS in CA]

Re: Dc power supply blow up! (QW-MS3010D)

It looks to me like the heatsink shorted out the circuit traces? I found this for a MS-605D but I think it is close.

That was my thought as well. The pitting on the bottom of the heatsink lines up with the trace that is partly missing. I don't see any insulator to prevent arcing. The other heatsink seems to have traces running under it, too. So I'd be nervous about that heatsink as well.

[eccerr0r]

Re: Dc power supply blow up! (QW-MS3010D)

Nice... it was using soldermask to insulate the heatsink from the trace?!!? wow!!!

[budm]

Re: Dc power supply blow up! (QW-MS3010D)

Nice... it was using soldermask to insulate the heatsink from the trace?!!? wow!!!

Anything goes for them to save money.

[eccerr0r]

Re: Dc power supply blow up! (QW-MS3010D)

Maybe it's a good idea to tear apart every MIC device I come across, to look for silliness like this...

[stj]

Re: Dc power supply blow up! (QW-MS3010D)

i do.
visual inspection before powerup every time.
not just china stuff btw, trust nothing - you may live longer or avoid some smoke!

[eccerr0r]

Re: Dc power supply blow up! (QW-MS3010D)

I just hope it's not warranty-voiding whether I break something while inspecting it or not!

[sam_sam_sam]

Re: Dc power supply blow up! (QW-MS3010D)

Most of the time I do not care if I void the warranty or not

whether I break something while inspecting it or not!

This is the part I worry about