System cannot complete POST

[Jagwire]

I recently shoehorned an AMD 4870 card (a gift) into a machine with an ASUS P5KE mobo and a 450 watt Cooler Master Power supply (Intel Quad core processor, 4 gb RAM, too many drives). I know: not enough power. Well it worked for a while. Now I get to the final posting screen, checking NVRAM, and then just a blinking cursor. There is no case speaker for beeps. Methinks it is the power supply and not the RAM. Going down to one stick makes no difference.

As I do not have another larger power supply hanging around to swap in, nor the ability to check the voltages, do those who know think it a safe bet
that a new 600 watt PSU should fix things?

[Aikonik]

HD 4870 is listed as 130W here. 130W/12V = 10.83A

http://www.xbitlabs.com/articles/vid...x280amp_5.html

Four disk drives would be 2.4A from +12V. A CDROM drive would be 1.5A from +12V, but only with media present. Cooling fans might draw 0.5A from +12V. Total 12V1 is 15.23A . A typical quad core might be 105W. 105W/12V * (1/0.90) = 9.72A total for 12V2

Total power = 12*(15.23+9.72) + 50W (mobo/RAM) + 4x5W (drives, 5V load) + 7.5W (CD, 5V load) + 10W (standby rail) = 336.9W

On paper, the 450W might be enough - it just depends on the 12V1 current rating. The above power numbers are maximums, and at POST, the currents will be a lot lower than the ones listed. The only way to get those numbers, might be in a gaming situation, with a game that can run all four cores flat out. And that isn't likely to happen.

Hard drives draw more current, for the first 10 seconds, and modern drives draw 2.5A each during that period. Once the platters are spinning, the current drops back to the 0.6A or so level. If the media hasn't finished spinning up, when the cursor starts to blink, it could be related to spinup current.

I'd start by removing some hardware, and seeing if you can get past the blinking cursor thing. It could be a RAM problem, or a single bad drive, or media still present in your USB card reader etc.

Since you can see the cursor, that means the processor is working, and enough RAM works for the BIOS to start running.

[Jagwire]

I managed to use a second power supply and a second video card and the same problem happens. Unfortunately I do not have access to other RAM modules or another mobo to find what the problem is.

[Aikonik]

Disconnect any drives that aren't absolutely necessary. *Make sure* there are no USB sticks, USB card readers or the like, with media in them. Like leaving a camera memory plugged into your card reader.

If all drives were disconnected, then you'd think you'd get past the point of complaints from the BIOS, and eventually the BIOS would tell you there is no boot system.

With all storage except the floppy disconnected, try a DOS boot floppy.

With only a CDROM connected, try booting your Windows installer CD, or a Linux LiveCD if you happen to have one available (Knoppix or Ubuntu are examples). Those distros don't need a hard drive to boot.

I'm not getting the feeling that you've trimmed a lot of hardware from the configuration yet.

It is probably something other than power, because with the 4870 replaced with something else, that is half the potential power right there.

I'd still concentrate on storage for the moment, and unplugging stuff. Keep track of what ports they were plugged into, in case that is important to your config. (Some boards have separate RAID controllers and the like.) Maybe a bad drive is holding the system hostage.

You can also try clearing the CMOS. There is usually a jumper on the motherboard for that. The usual procedure, is to disconnect the AC power from the wall, before using the jumper. After clearing the CMOS, the system time should be reset, and you'll have to reenter any custom BIOS settings. Not that handy, if you don't happen to remember what you
changed.

[Jagwire]

Thanks for your suggestions. I have tried all that you suggest but the system still stops at a blinking cursor. I have reset the bios and the optical drive is set as the first boot-up drive but I do not get the option to boot from a CD. I think it is the motherboard, which never worked exactly properly to begin with (the IDE port never functioned).