Power button not powering on, but powers by reattaching power cable, still no video

[nilandenterpris]

Power button not powering on, but powers by reattaching power cable, still no video

I have tried a different monitor, No joy. only powers on but removing the power cable for a few seconds and reattaching, but no video output

I have checked the new 3 volt battery, it is @ 3.1v

I have used the crisis recovery jumper, no joy

There are no beeps or LED errors

The power supply LED is green when powered on

I have checked the power supply voltages to the Nvidia dual DVI card and if left detached I do get Beep Error

I have reseated the RAM (32Gb)

Thanks James

Update:

Power supply BIST* LED lights work with all connectors disconnected

Power supply BIST* LED lights work with all connectors connected; connecting power cord unit fan come on, BIST  LED green, but no video

Power button held for four seconds power downs the unit, but then the BIST LED is no longer on and power button will not turn unit back on. Have to remove power cord and reinsert to get green BIST LED, unit powers up but no video

disconnecting the video power connector (P16)  gives error beeps

The 24-Pin Main power connector pin out dose not seem to correspond: pin 12 +3.3 V and pin 23 +5 V is missing or blank

There is no info I can find about the motherboard standby connections. Most motherboards supply either 5v or 3.3v standby voltage to power up the unit, but I seem to loose this once powers down. I din't know what pin this would be on the motherboard?

Also the HP repair listing is very much outdated

4-Pin power (memory system board) connector all working

8-Pin power (for CPUs and on board regulators) connector all working

6-Pin power (auxiliary PCI Express) all working

Additional, since this is a water cooled xw9400 with 8 core opteron's this has the DPS-1050CB (1050Watt) higher power supply # 4408608-001

In NC any repair shops are a 4 hour drive from me so I am on my own

I would like to find the failed circuit and replace the parts as I have the skills and the SMD re-work station,but I would rather not do hit and miss

[nilandenterpris]

Update:

Power supply BIST* LED lights work with all connectors disconnected

Power supply BIST* LED lights work with all connectors connected; connecting power cord unit fan come on, BIST  LED green, but no video

Power button held for four seconds power downs the unit, but then the BIST LED is no longer on and power button will not turn unit back on. Have to remove power cord and reinsert to get green BIST LED, unit powers up but no video

disconnecting the video power connector (P16)  gives error beeps

The 24-Pin Main power connector pin out dose not seem to correspond: pin 12 +3.3 V and pin 23 +5 V is missing or blank

There is no info I can find about the motherboard standby connections. Most motherboards supply either 5v or 3.3v standby voltage to power up the unit, but I seem to loose this once powers down. I din't know what pin this would be on the motherboard?

Also the HP repair listing is very much outdated

4-Pin power (memory system board) connector all working

8-Pin power (for CPUs and on board regulators) connector all working

6-Pin power (auxiliary PCI Express) all working

Additional, since this is a water cooled xw9400 with 8 core opteron's this has the DPS-1050CB (1050Watt) higher power supply # 4408608-001

In NC any repair shops are a 4 hour drive from me so I am on my own

I would like to find the failed circuit and replace the parts as I have the skills and the SMD re-work station,but I would rather not do hit and miss