CEMO:ATX-500W-24P (+5vsb shorted)

[LENOVO-A880]

Diagnosing A Dead ATX-500W-24P PSU *Identical* Knock Offs From China

Hello everyone I have a problem with my power supply. The PSU in any way is not powering on (no green light and fan is not spinning). When opened it up I found short on +5Vsb. I had removed 2 bulge capacitors in that line and still trying to find out the main problem here. These are some of the basis findings which I have done :

1. Suspect a short circuit on the main board. The suspected component are the filter capacitors and power transistors. A faint smell comes from the board and suspected to be an overheating MOSFET. A few months ago the power supply actually had failed to power on my PC which has probably a dead mother board. Pls refer to this link of the thread here for the dead motherboard (https://www.badcaps.net/forum/showthread.php?t=38542)
2. Check that the fuse is usually still good from my inspection. Before proceeding to further diagnosing the problem of the power supply I think to actually replace the capacitors with good one first except for the power transistors.
3. Inspect the solder-side of the board and found burning sign on one of the components near the transistor/transformer combination. The main board soldering is really quite bad from my inspection just after removing the heat sinks and live wires.
4. Have not attempt to use a multimeter to check for proper voltages on the pin-3 and pin-9 of the ATX to main board supply

Questions

1. What type of series of capacitors should be changed here as a proper capacitors replacement to the dried up capacitors on the C507 and C508 label capacitors which has rating of 470uF/16V and 1000uF/10V? Main manufacturers like Panasonic recommended us using the EEU-FC series capacitors for a replacement.
2. Where can I purchase this type of capacitor for a replacement to the dried up capacitors? Digikey?
3. What is the best practice to replace the dried up capacitors of this kind of board?
4. How can I check the voltages between pin-3 and pin-9 of the ATX to main board connector. Should I also check the main voltages of the primary side or primary power voltage as well before proceeding to another further test?

[budm]

Re: CEMO:ATX-500W-24P (+5vsb shorted)

You can use FR series also, they are made in Malaysia.

You should look at the ESR value of the FC and compare to FR to make sure that sometime too low of the ESR can cause problem.

[stj]

Re: CEMO:ATX-500W-24P (+5vsb shorted)

worth adding, if the FR/FC caps are too large, you can get compact FK versions.

[goodpsusearch]

Re: CEMO:ATX-500W-24P (+5vsb shorted)

It is not worth fixing in my opinion.

[new2019]

Re: CEMO:ATX-500W-24P (+5vsb shorted)

You have same problem as mine , you will have a short circuit in the primary side which extends to secondary side .

[ben7]

Re: CEMO:ATX-500W-24P (+5vsb shorted)

This uses the infamous 'two-transistor' design for the 5vsb. I've seen them fail and put out 20+V, killing the motherboard. I recommend replacing ALL the electrolytic capacitors on this board.

Take a look and see if the 5vsb rail has any shorted diodes on it.