ML150 Won't Power Up

[Richard Stoliar]

I have an ML150 G5 E5405 QC with 1GB memory and 2 x 250GB disks.

It had not been used for about 3 months, although it had been plugged into the power. When I recently tried to start it, pressing the power button did nothing even though the power LED was amber which I believe means standby.

Removing the power cable completely, leaving for a few seconds, and then plugging in leads to the following:

* The fan(s) operate for about 5 seconds then power down
* At the same time, on the front panel the Power LED goes green, then the HD LED goes green and then finally the health check goes green. After a couple of seconds, both health check and HD LEDs turn off and the power LED turns amber (this at the same time as the fans stop).
* Looking at the motherboard, when the power cord is connected, LED6 by the power connector turns green and remains green the entire time the power cord is connected. LED11 (unsure what this is) just below the battery flashes red once just as the fan starts up. Another unknown LED just to the right of the PCI slots flashes green the entire time the power cord is connected.
* In the PSU, a green LED lights up when the power is connected and then goes off at the same time as the fan.

I have removed all cards and all the disks and the same thing happens. If I remove the 2 DIMMs in the memory slots I get 4 beeps as soon as the power cord is plugged in. (Re-inserting them then leads to the previous behaviour where no beeps are heard).

I have pressed the CMOS reset button below the battery to no avail and have also removed the battery for 5 minutes, also to no avail.

Any suggestions?

Many Thanks,

Rich

[Bob Salomon]

try reseating the CPU

bob

[Richard Stoliar]

Thanks for your reply Bob. I have tried this but no luck, the same thing happens.

Thanks,

Rich

[Richard Stoliar]

In the end HP sent some engineers round and after replacing the motherboard and then the PSU - to no avail - it was discovered that a known problem involved the power cable from front panel to motherboard. So a replacement was ordered and when the engineer replaced the old for new, it fixed the problem.

[ICS Computers]

Are you sure that it was the power switch? HP told me it was the temperature sensor, and I replaced it with no change. I will try the power supply next, but no guarantees at this time that it will work. Why won't HP publish the meaning of those LED lights, so that we can figure out what is wrong?