Board LED lit, No Power, Won't boot

[kopfjaeger]

Gents,

Have been tasked with taking a 2d-hand Abit BX133-RAID http://www.abit-usa.com/products/mb/...es=1&model=107 and turning it into a friend's free machine. The board came with an Intel Pentium III Coppermine 800/256/133/1.75 -- that's it.

I have tested 3 different ATX power supplies, each of them tested with a dedicated PSU tester.


TEST CONFIGURATION

- Barebones, only a video card. Have tested it with both an AGP card and a PCI / VGA video card, same results.

First, with 2 x PC100 / 128 MB DIMM SDRAM modules, then with a replacement single PC100 / 128 MB DIMM SDRAM module in DIMM1 (where DIMM1, DIMM2 & DIMM3).

CD / HDD/ FDD are connected in respective IDE ports.

CPU fan is connected directly to PSU by Molex connector



SYMPTOMS

Power LED on mainboard comes on. No other activity. Zilch, nix, nada.

Pull power connector from board and run PSU test, leaving other Molex connectors fastered to CPU Fan, CD / HDD/ FDD - > CPU and PSU fans spring to life.

Checked capacitors for signs of swelling, brown leakage, showing overheating, melting = no visible signs of either symptom.


MY GUESS

PSU(s) check out as good. Note, none are Dell proprietary PSUs, one even states 'for Pentium.' Power is getting into the mainboard, at least as far as the mainboard's on-board power LED (not to be confused with Power LED on the front of the case). But something within the mainboard's circuit not allowing power to the rest of the system.


QUESTION

- Possible causes and cures?


Thanks in advance.

KJ

[DanU]

I'm going from memory here, but I don't think you can run PC100 RAM and a 133MHz FSB cpu at the same time with the 440BX chipset. It doesn't have the necessary 3/4 memory/FSB divider. Have you reset the CMOS and tried putting the CPU FSB to 100MHz?

[kopfjaeger]

Hello Dan,

No I have not done either. I'll have to give that a shot. Actually, I thought I'd had that covered by checking out the manual and setting the DIP switches in the following manner:

1-4 set as a multiplier of 8

5-8 set FSB at 100 == for a CPU that was 800 Mhz

DIP's 9-10 had to be set for manual configuration, rather than done by the software in BIOS setup.

I have some PC133 memory that I can try, do you think by resetting the CMOS jumper and using a PC133 module, that it might at least give me some power and images on the screen?

Thanks. Good thing I didn't toss the board just yet.

KJ

[DanU]

The P3 is a locked multiplier CPU. The multiplier jumpers will be ignored.

With a FSB of 100MHz, the P3-800/133 will run at 600MHz.

Make sure your AGP divider is set to 2/3, using jumper DS9.

[kopfjaeger]

Quote:

The P3 is a locked multiplier CPU. The multiplier jumpers will be ignored.

With a FSB of 100MHz, the P3-800/133 will run at 600MHz.

Thanks for the additional info.

600 MHz???? Dang! I've been juked!

That's crazy. Under-clocking?

Quote:

Make sure your AGP divider is set to 2/3, using jumper DS9.

[kenboyles72]

try it with just cpu, video and ram. also is the system speaker connected. if not connect one and see if you get any warning beeps.

[DanU]

Personally I would set the jumpers to OFF. This will activate Softmenu, so you can change the FSB conveniently in the BIOS, rather than have to open up the case and fiddle around with annoying jumpers.

Set your FSB to 133MHz via either the jumpers or softmenu (preferred) and you'll be running the CPU at 800MHz (6X133).

The AGP divider controls how fast the AGP port runs. It has no bearing on how fast the CPU runs.