Power Supply Bad? Need Help!

[aba4430]

Hello,

I am building 3 new computers, all identical except for different sets of 4 GB DDR2 memory. Two are for family members and one for us. I am using the following:
1. Antec Sonata Plus 550 (this one has Neo 550)
2. Asus P5Q Pro
3. Q6600
4. OCZ reaper, Corsair or Patriot 4 GB memory (2 X 2 GB modules)
5. Samsung 22X Lightscribe burners
6. Samsung 500 GB SATA HDs
7. Sony 3.5" internal card reader
8. PNY 8800GT cards
9. One extra 92 mm intake fan on the Sonata Plus
10. Vista Home Premium 64

I started on all 3 units yesterday and installed MBs, drives, CPUs etc. However completed one unit testerday and all went well. So I put it away.

Finshed the remainder of the second unit this evening and turned it on. The green LED on the P5Q Pro lit up, but nothing else. How can I test the PS to determine whether it is bad. This is what I did - and I feel I am missing something: I turned the PS switch off and then unplugged the 8 pin power connector. It is supposed to have +12 volts on 4 pins on same side and ground on the other 4 pins. My voltmeter read 0 volts. Perhaps I am not testing it correctly. I unplugged the connector and then turned the power on. Then I tested it with my voltmeter, but no readings. I have not tested the 24 pin connector as yet.

Hopefully it is my PS, not the MB, as it will be a pain to redo everything. Any help is appreciated.

aba4430

 

[aba4430]

I just shorted the power on pin (green wire) and an adjacent ground (black wire) on the 24 pin connector and no response. The green light on the MB is on, but nothing else.

 

[mpilchfamily]

You got the hot wireing right but you don't want it plugged into the motherboard when you do it. Unplug the PSU from everything and then power it up. Make sure the switch in the back is turned on. Now place the black lead of the DMM in with the black wire of one of the connectors. Place the Read lead in with the yellow wires of the connector and you should read 12V +/-5%. If it checks out then you need to look into other things being the problem.

The fact that the green light on the motherboard comes on indicates that the PSU is sending some power. There could be many reasons its not powering up.

 

[aba4430]

Thanks for your response and leads. I unplugged all PS related connectors from the MB and turned on the PS. Against a ground on the 24 pin plug, only the green PSON and violet STANDBY pins show any voltage. The green one indicates 2.571 volts and the violet one 5.04X volts. Everything else is 0.000 to 0.002. The 8 pin power connector also indicates 0.002 volts on each of the 4 yellow leads. Is my Neo 550 dead? Are there any other checks I can do? I will contact NE today for RMA on this unit. I hope they can send me just the PS unit, rather than RMA-ing the entire case......
Appreciate it.

 

[Modelworks]

2.5V is normal for the green wire. And standby should be 5v when the power supply is not turned on with the green shorted to ground.
If you short the green to a ground the supplies fan should start spinning and then you should be able to measure voltages on the other pins.
Some power supplies will not start without a load so you may need to connect a hard drive to one of the connectors to get it to start and stay on.
The main voltages are 3.3V on orange, 5V on red, 12V on yellow , 12v on the 8 pin. If all those are there then it should work.

 

[aba4430]

Thanks for the response. I am stumped now. I jumpered the PSON and a ground with one modular cable connected on the PS. The 12 V power connector was unplugged. The PS fan came on in a second or two. I could measure 12, 5 and 3 volts on the 24 pin connector and the 8 pin connector read 12 volts on the yellow cables. I connected all the cables again and same issue. The standby LED on the P5Q Pro is lit, but nothing else. I thought the case power switch was perhaps faulty - so I used a screw driver to jump the power on pins on the MB, but no-go. I guess the PS checked out OK??? Are there any leads on checking the MB?

 

[mpilchfamily]

Yep sounds like the PSU is fine. Now you need to pull everything out of the case and set it up on some cardboard. This helps rule out a short. Only have the bear esentials installed. CPU, single Dimm of RAM, Video card and the PSU. If it still doesn't turn on then try the RAM in different slots. Then change out and use the other Dimm. It will also help to get a speaker plugged into the motherboard so that you can hear any beep codes that it may produce. If your still getting no responce from the motherboard in the way of things powering on then its time to RMA the board.

 

[aba4430]

I spoke to Antec yesterday. The CS rep suggested that I swap the power supply from my 3rd unfinished unit into this one, for the quickest check. Will see what happens. If this does not work, I will take it all apart and start checking my assembly etc. Thanks, I truly appreciate the assistance.

 

[aba4430]

Update: Removed the PS from the 3rd partial build and tried it on the non-working unit. No-Go. Then I completed the 3rd computer and crossed my fingers and powered it up. Exactly the same problem as the second one. The green LED standby indicator was on, but nothing else. I contacted Asus - The representative appeared very busy and tried to hurry me through a check on my 3rd unit. He had me pull the CPU off and power the unit on; however no go. He said that my MB was most likely bad and to RMA both MB's through Newegg. I found it funny, I mean I was expecting him to walk me through voltage checks, jumpers, visual cues - nothing. However, I am done with the Asus P5Q Pro MBs. I cannot believe that two of the three units were defective. I am RMA'ing all three units. I have not given up on Asus as yet. This morning, I ordered 3 P5Q Deluxe boards. These are a bit pricier, but have received good reviews. Hopefully, they will work out.
Appreciate all the help here.