Asus P5A-B - locks on boot after changing power supply

dsjonz · 12th March 2002, 8:21 AM

My P5A-B runs fine with my old AT-tower 230w unit plugged into the AT power socket, but when I try to use any other AT 220-230w power supply in the AT power socket, or my new Enermax 430w unit in the ATX socket (with the switch plugged in), my system locks after the "Award BIOS Extension v1.0a" message. This message occurs just after the RAM is successfully checked, and just before the PNP messages. The only upgrade I've made to the board since I bought it was installing the latest P5A-B
"1010" BIOS upgrade.

This condition occurs with no other changes to the system. I've tried: clear & reset the CMOS, both default and setup BIOS settings, all PCI cards taken out except for graphics, power management off, all devices connected/disconnected, BIOS
boot virus protection off. I'm running an AMD K6-2/500 OC'd to 550, 578mb PC133 RAM, ATI All-in-Wonder Pro 128/32mb, 40gb ATA 100 disk, with Windows XP Professional.

Frankly, I'm embarrassed to be so stymied by this. Any ideas?

Oblong Cheese · 12th March 2002, 7:19 PM

Is there a jumper somewhere to switch between using an AT or an ATX PSU? Do you have the manual for the motherboard, have you had a look through it? I used to have this board, in the manual it says this about ATX power supplies:

"Make sure that your ATX power supply can supply at least 10mAmp on the 5-volt standby lead (+5VSB). You may experience difficulty in powering on your system if your power supply cannot support the load. For Wake On Lan support, your ATX power supply must supply at least 720mA."

Also, have you tried swapping around RAM modules? Maybe one has stopped working.

D F · 12th March 2002, 10:28 PM

I am speaking from experience here, When I was trying to get the compaq psu working in my pootapack, It would have the same symptoms you experienced, it would lock when booting, but in my situation it would lock at random times. I knew that that was the only supply I was going to use for a long shot, so I check the pins, and thought they were a little loose (useing at connector). I poped out the pins, and bent them out more so they made better contact with the mobbo pins. Lo and behold, it worked. .. .

dsjonz · 12th March 2002, 11:43 PM

I rechecked the ASUS PDF manual for any reference to any kind of PSU jumper (or 'solder jumper' like the one used to clear CMOS settings on this board). Nada. This ASUS P5A-B Baby AT Socket 7 board has two power connectors - one for older AT PSU's, and one for ATX PSU's.

I've got two spare 220w AT-type PSU's and a new 413w Enermax EG465P-VE ATX PSU. The strange thing is that the lockup behavior occurs with *both* types of PSU's - it is as if it is stuck on using just the 230w AT PSU that has powered the board since I built it a couple of years ago.

As for the RAM, the lockup occurs *after* POST, *after* the RAM checks out OK, at the end of the 'AWARD BIOS Extension v1.0' message showing onscreen, just before the 'PNP devices loaded' usually appear. It's an unvarying routine: I unplug the old AT PSU and plug in one of the other AT PSU's into the AT power socket and I get the lockup. Or, I unplug the old AT PSU and plug in the new Enermax ATX PSU into the ATX socket and get the same result - lockup.

It's the damnest thing - again, it is as if the motherboard is stuck on using just this particular 230w AT PSU, one that I need to replace because of low & ragged voltages. I'm getting only 11.3v on the 12v line, and 4.7v on the 5v line with it. This is marginally acceptable voltage for my K6-2/500 OC'd to 550(100 bus x 5.5) or 578 (105 bus x 5.5), but I hear that erratic stability will be exhibited with anything less than 4.8v on the 5v line. I'm getting this 'erratic stability' under Win XP Pro no less, hence, my need to solve this perplexing problem.

Oblong Cheese · 14th March 2002, 6:37 PM

I'm not too sure about your PSU problem, but set your CPU FSB and multiplier to 110x5.0 - This will result in a 561Mhz core speed. It is documented at 110Mhz, but in actual fact it is 112Mhz. I know this because I used to run my K6-2 at this speed.

Upping the FSB creates a much larger performance gain that changing the multiplier, due to the L2 Cache running at FSB speed.

dsjonz · 14th March 2002, 10:59 PM

I've often wondered at others who seem to push the FSB with such ease on the K6-2. The best my setup will allow is 105mHz . . .I've tried every higher FSB setting variation with no success. I'm running PC133 SDRAM with it, and I've tried various BIOS setting changes to allow for a higher FSB (CAS, etc.) but to no avail. It won't go above a 5.5 multiplier, and it won't go faster than 105mHz. Oh, well . . .

Thanks to those who offered suggestions to crack my PSU mystery. I decided to solve it another way - I'm replacing the motherboard with an MSI K7T266 Pro-RU, coupled with the cheapest Athlon I can get my hands on.

Another side note. I'm on this forum because I frankly admire the tenor and attitude of the Aussies here. This southern American (living in Canada) gets a charge out of reading the exchanges here.

Dsjonz

12th March 2002, 8:21 AM	#1
dsjonz Member Join Date: Mar 2002 Location: Canada Posts: 5	Asus P5A-B - locks on boot after changing power supply My P5A-B runs fine with my old AT-tower 230w unit plugged into the AT power socket, but when I try to use any other AT 220-230w power supply in the AT power socket, or my new Enermax 430w unit in the ATX socket (with the switch plugged in), my system locks after the "Award BIOS Extension v1.0a" message. This message occurs just after the RAM is successfully checked, and just before the PNP messages. The only upgrade I've made to the board since I bought it was installing the latest P5A-B "1010" BIOS upgrade. This condition occurs with no other changes to the system. I've tried: clear & reset the CMOS, both default and setup BIOS settings, all PCI cards taken out except for graphics, power management off, all devices connected/disconnected, BIOS boot virus protection off. I'm running an AMD K6-2/500 OC'd to 550, 578mb PC133 RAM, ATI All-in-Wonder Pro 128/32mb, 40gb ATA 100 disk, with Windows XP Professional. Frankly, I'm embarrassed to be so stymied by this. Any ideas?

12th March 2002, 7:19 PM	#2
Oblong Cheese Member Join Date: Aug 2001 Location: Brisbane Posts: 9,850	Is there a jumper somewhere to switch between using an AT or an ATX PSU? Do you have the manual for the motherboard, have you had a look through it? I used to have this board, in the manual it says this about ATX power supplies: "Make sure that your ATX power supply can supply at least 10mAmp on the 5-volt standby lead (+5VSB). You may experience difficulty in powering on your system if your power supply cannot support the load. For Wake On Lan support, your ATX power supply must supply at least 720mA." Also, have you tried swapping around RAM modules? Maybe one has stopped working. __________________ My Website \| My Computers \| Grado Labs Alessandro MS-1, Shure SRH-840, Topping TP30

14th March 2002, 6:37 PM	#5
Oblong Cheese Member Join Date: Aug 2001 Location: Brisbane Posts: 9,850	I'm not too sure about your PSU problem, but set your CPU FSB and multiplier to 110x5.0 - This will result in a 561Mhz core speed. It is documented at 110Mhz, but in actual fact it is 112Mhz. I know this because I used to run my K6-2 at this speed. Upping the FSB creates a much larger performance gain that changing the multiplier, due to the L2 Cache running at FSB speed. __________________ My Website \| My Computers \| Grado Labs Alessandro MS-1, Shure SRH-840, Topping TP30

12th March 2002, 10:28 PM	#3
D F Member Join Date: Jun 2001 Location: Sydney Posts: 1,308	I am speaking from experience here, When I was trying to get the compaq psu working in my pootapack, It would have the same symptoms you experienced, it would lock when booting, but in my situation it would lock at random times. I knew that that was the only supply I was going to use for a long shot, so I check the pins, and thought they were a little loose (useing at connector). I poped out the pins, and bent them out more so they made better contact with the mobbo pins. Lo and behold, it worked. .. .

12th March 2002, 11:43 PM	#4
dsjonz Member Join Date: Mar 2002 Location: Canada Posts: 5	I rechecked the ASUS PDF manual for any reference to any kind of PSU jumper (or 'solder jumper' like the one used to clear CMOS settings on this board). Nada. This ASUS P5A-B Baby AT Socket 7 board has two power connectors - one for older AT PSU's, and one for ATX PSU's. I've got two spare 220w AT-type PSU's and a new 413w Enermax EG465P-VE ATX PSU. The strange thing is that the lockup behavior occurs with both types of PSU's - it is as if it is stuck on using just the 230w AT PSU that has powered the board since I built it a couple of years ago. As for the RAM, the lockup occurs after POST, after the RAM checks out OK, at the end of the 'AWARD BIOS Extension v1.0' message showing onscreen, just before the 'PNP devices loaded' usually appear. It's an unvarying routine: I unplug the old AT PSU and plug in one of the other AT PSU's into the AT power socket and I get the lockup. Or, I unplug the old AT PSU and plug in the new Enermax ATX PSU into the ATX socket and get the same result - lockup. It's the damnest thing - again, it is as if the motherboard is stuck on using just this particular 230w AT PSU, one that I need to replace because of low & ragged voltages. I'm getting only 11.3v on the 12v line, and 4.7v on the 5v line with it. This is marginally acceptable voltage for my K6-2/500 OC'd to 550(100 bus x 5.5) or 578 (105 bus x 5.5), but I hear that erratic stability will be exhibited with anything less than 4.8v on the 5v line. I'm getting this 'erratic stability' under Win XP Pro no less, hence, my need to solve this perplexing problem.

14th March 2002, 10:59 PM	#6
dsjonz Member Join Date: Mar 2002 Location: Canada Posts: 5	I've often wondered at others who seem to push the FSB with such ease on the K6-2. The best my setup will allow is 105mHz . . .I've tried every higher FSB setting variation with no success. I'm running PC133 SDRAM with it, and I've tried various BIOS setting changes to allow for a higher FSB (CAS, etc.) but to no avail. It won't go above a 5.5 multiplier, and it won't go faster than 105mHz. Oh, well . . . Thanks to those who offered suggestions to crack my PSU mystery. I decided to solve it another way - I'm replacing the motherboard with an MSI K7T266 Pro-RU, coupled with the cheapest Athlon I can get my hands on. Another side note. I'm on this forum because I frankly admire the tenor and attitude of the Aussies here. This southern American (living in Canada) gets a charge out of reading the exchanges here. Dsjonz