Jou Jye JJ-300AP 300w Fail

[willawake]

This is a friend's psu. Turned it on one time and burning smell. Then turned it on a second time! (electrician by profession)

Between the two main caps there is a ceramic capacitor which has burnt. There appears to be leaking from the bungs of the main caps which has travelled up onto the pcb on the top near the fan. (as the psu would have been upside down in the case) i am not sure about that though. All the caps are Jun Fu.

There is no burning on the ATX or 12v mobo connector.

anybody have any idea about the reason for the fail?

[Rainbow]

Re: Jou Jye JJ-300AP 300w Fail

Are you sure it was a ceramic cap? They rarely fail.

[willawake]

Re: Jou Jye JJ-300AP 300w Fail

the pcb says ZNR1 for that item and there is another one right behind it in the photo (the brown one) marked ZNR2.

might not be the cause though, it might be the effect.

[Rainbow]

Re: Jou Jye JJ-300AP 300w Fail

I'd say it was a varistor - for overvoltage protection.

[larrymoencurly]

Re: Jou Jye JJ-300AP 300w Fail

Is the blown component a ceramic capacitor, or is it a zener or MOV? Because next to it the circuit board is labelled "ZNR1", which could stand for ZeNeR1. Could that mean there was a voltage surge?

If this PSU failed the very first time it was used, then maybe it was built for 110V instead of 220V. I don't see a voltage selection switch on back, and all the PSUs I've seen that had automatic voltage selection had only one big high voltage capacitor, not two, but maybe a jumper was wired when it shouldn't have been.

[willawake]

Re: Jou Jye JJ-300AP 300w Fail

PSU was working fine for 3 years and then failed. It is a 230v unit. ZNR appears to be in common use on pcbs for ZNR Surge Absorber (varistor) / Zinc Oxide Nonlinear Resistor / MOV etc. So thanks for that tip.

I guess we are indeed talking about a surge from the wall unless the MOV failed on its own?. Fuse is not blown though. Might be a good idea to recommend a UPS.

Here is an interesting article on Metal Oxide Varistor Degradation
http://www.iaei.org/magazine/04_b/04_b_brown.htm

I am thinking the brown stuff is not from the caps, just some wierd glue. it is also in another place (near the fuse) and looks like it did not flow there.

Would it be repairable if i salvage some varistors from another unit, or would there be more damage? I dont see anything obvious. I hope the pc is ok but since it took 2 weeks to remove the psu from the case i think we will have to wait for a while for that news to arrive.

[Rainbow]

Re: Jou Jye JJ-300AP 300w Fail

I think it should work after replacing the MOV.
Nice photo in that article - http://www.iaei.org/magazine/04_b/brown_photo1.gif

[linuxguru]

Re: Jou Jye JJ-300AP 300w Fail

Just replace the varistors with ones with equivalent voltage rating - somewhere between 200-250 V DC will be fine across each cap. The fuse and the bridge rectifier should also have gone. Check the other stuff on the primary side carefully, including transistors, inrush thermistor, etc.

[Per Hansson]

Re: Jou Jye JJ-300AP 300w Fail

I've had that happen to an Enermax PSU... It was a 420w model if I'm not mistaken, a Zenerdiode failed, probably due to a spike or surge in the powergrid...

I went down in the basement and stole a smaller one from a dead PSU, it's the size of them that determines how much they can handle before they fail... It's been running fine since that day, prolly more than two years ago now...

[willawake]

Re: Jou Jye JJ-300AP 300w Fail

friend is ordering a fortron bluestorm 350w as replacement and an APC br 500i. I am hoping that 500va is ok for a basic p4 system with 17" tft (usually i spec ups higher for the office to have longer battery backup, like 800va) anyway they want to minimise cost but still buy decent products.

so looks like that psu is mine for project repair. hehe. (if i dont post again, you can guess what happened). it doesnt look like a bad unit though and suprising to see one with active pfc in a cheap case.

[japlytic]

Re: Jou Jye JJ-300AP 300w Fail

On the PCB near the fan with a burn mark: I think it looks like the PFC module (which probably has a blown MOV).
Those 220uF 200V electrolytics are inadequate for a 300W supply... suggest replacing them with 470uF or higher units, board space permitting, as well as replacing the Jun Fu electrolytics on the secondary.

[kc8adu]

Re: Jou Jye JJ-300AP 300w Fail

the larger caps will also allow you to ride through minor glitches.

[MD Willington]

Re: Jou Jye JJ-300AP 300w Fail

And this was attached to the "lovely" power system in Greece I take it. How's the voltages in your friends area?

MD

[willawake]

Re: Jou Jye JJ-300AP 300w Fail

And this was attached to the "lovely" power system in Greece I take it. How's the voltages in your friends area?

probably shitty. better in the city. things have improved a lot since the 80s though.

[Per Hansson]

Re: Jou Jye JJ-300AP 300w Fail

Haha, that is excellent bro!

You should see my graphs.... I don't have any software to make a nice graph though, unless you want to see the graph from my APC Smart-UPS 1000 UPS connected after the Riello 6kW UPS


Now where are those spikes

[dood]

Re: Jou Jye JJ-300AP 300w Fail

I didn't think you were supposed to plug a UPS into another UPS... And why would you want to?

[Per Hansson]

Re: Jou Jye JJ-300AP 300w Fail

I didn't think you were supposed to plug a UPS into another UPS... And why would you want to?

There will be no harm...

Why? Well, I got it basically for free... And it should offer better protection against lightning strikes...

I've got another Smart-UPS 700 in a corner doing nothing, maybe I should hook it up aswell :P

[MD Willington]

Re: Jou Jye JJ-300AP 300w Fail

I know some other guys living in Greece, UPS has saved their systems more than once. I also know that several large companies have no trust at all in the government utilities and they run their own power systems...

MD

[RJARRRPCGP]

Re: Jou Jye JJ-300AP 300w Fail

This is a friend's psu. Turned it on one time and burning smell. Then turned it on a second time! (electrician by profession)

Between the two main caps there is a ceramic capacitor which has burnt. There appears to be leaking from the bungs of the main caps which has travelled up onto the pcb on the top near the fan. (as the psu would have been upside down in the case) i am not sure about that though. All the caps are Jun Fu.

There is no burning on the ATX or 12v mobo connector.

anybody have any idea about the reason for the fail?

The brown stuff around the big caps likely is just glue! It's possible that the glue melted and thus ran across other components! Does the fan still work and work properly? What I'm looking at may be just an overheat problem.

[willawake]

Re: Jou Jye JJ-300AP 300w Fail

fan is working and good.