Cooler Master GX 620w (rs-620)

[manounours]

Hello,

i have a dream... a dream that i can repair my psu but it's not easy.

What's the problem ?

In first time, this psu don't want to start immediatly. When i try to power on my computer, the psu start and stop : a red led light at the rear of the psu.
I switch off the electrical power button then switch on and try to start my computer and the problem restart.
I do this action ten, twenty times and finally the psu start whitout activate security (no red led light). No problem, the pc is ok.

one month later, the problem is always here but the number of try increase and now it's impossible to start. The security is always activated.

So, I decide to open this psu. i've notice that the board is print pc6022( which is an in reality an ACBEL psu). The security is supported by two chip : FP131 and WT7510

All caps are ok (mesured a - 10% error)

But the main cap (150uF and 220uF) are measured together 340uF. Is this ok ?

I can't find any schematic diagram or information on this psu. Anyone can help me ???

Thank You,
Emmanuel

[ben7]

Re: Cooler Master GX 620w (rs-620)

Did you test the capacitors' ESR, not just capacitance? You know, capacitors can be fine capacitance wise, and have bad ESR! It does sound like the typical bad capacitor problem!

[manounours]

Re: Cooler Master GX 620w (rs-620)

No, i don't think at the ESR. Every time i repaired a psu and if capacitor is bad, i find it by it's bad capacitance.
But here, maybe this is the solution.

And.. how can you measured the capacitors'ESR ?

Thank you,
Emmanuel

[ben7]

Re: Cooler Master GX 620w (rs-620)

No, i don't think at the ESR. Every time i repaired a psu and if capacitor is bad, i find it by it's bad capacitance.
But here, maybe this is the solution.

And.. how can you measured the capacitors'ESR ?

Thank you,
Emmanuel

You will need an ESR meter. Even if it doesn't help for this problem, it will certainly be useful to have in the future!

[manounours]

Re: Cooler Master GX 620w (rs-620)

ok i find a esr meter or i build it and i'll say the result of my searching.

thank you
Emmanuel

[bobbyrae]

Re: Cooler Master GX 620w (rs-620)

In first time, this psu don't want to start immediatly. When i try to power on my computer, the psu start and stop : a red led light at the rear of the psu.
I switch off the electrical power button then switch on and try to start my computer and the problem restart.
I do this action ten, twenty times and finally the psu start whitout activate security (no red led light). No problem, the pc is ok.

one month later, the problem is always here but the number of try increase and now it's impossible to start. The security is always activated.

My Antec PS died in pretty much the same way. At first it would just stop after a few seconds, but then on the second attempt it would start OK. (The Antec did not have a red LED, though) I am going to guess the either the PS or the motherboard decided that the power was not OK somehow and aborts. Over time it got worse and worse until it wouldn't start at all.

Is there a standard cause associated with this symptom? Or maybe too many possibilities?

[ben7]

Re: Cooler Master GX 620w (rs-620)

Did you get an ESR meter yet?

[Heihachi_73]

Re: Cooler Master GX 620w (rs-620)

If the PSU doesn't power on the first time, don't force it, as you could risk damaging other components, particularly the mainboard. Wet caps, transistors and ICs generally don't like ripple current, and even a "good" PSU could damage an otherwise good system just because the ripple was way out of spec although the voltages may have been correct with everything seemingly working fine.

This is exactly what happened to my LCD TV - 3 Samxon caps initially failed in the PSU and wouldn't allow the TV to power on from standby, but after a handful of attempts it would turn on. I can't imagine what was going through the other components every time it failed, it ended up damaging one of the mainboard's caps in the process however (it only powered on twice after the initial failure before a 680uF TLC brand cap on the mainboard gave up, then it was dead "for good"... until I finally get around to recapping it).

[Pentium4]

Re: Cooler Master GX 620w (rs-620)

Need some pics

[manounours]

Re: Cooler Master GX 620w (rs-620)

Hello

No, i haven't find an ESR meter yet. But don't worry, i don't stop

[manounours]

Re: Cooler Master GX 620w (rs-620)

Hello,

Finally, i have the solution

I'l try to explain you why this psu was in security.

This PSu have three line +12V and when i see the pcb, there are 3 line and every line are protected by a ocp circuit.
This OCP circuit is composed by three IC. One IC = 1 Line +12V :
2 * FP120 (it's the same thing that FP131 whitout the photodrive comparator)

doc FP131 :


doc FP120 :


all OUT pin from these chip are connected to a diode like 1N4148. All cathod
arrive Pin 5 of FP131
So if one Chip detect anormal intensity, the OUT is high state => Pin 5 FP131 is High State and WT7510 stop PSU.
Here, there is one Chip which have OUT high state constantly but nothing is connected. This chip is out of service !
But i can't buy this chip because it's impossible to find. So i decided to remove it.
The PSU is now OK.

sorry i can't send you a picture of my problem because the board block every file !!!!

Thank you,
Emmanuel.