K6 vs. K6-2?

[monte]

I hope someone can help me solve this mystery which has been driving me crazy for a while:

I have an ASUS SP-97V rev 1.02 that has been running a K6 at 200/66 for years with no problems. I tried twice to upgrade to a K6-2, and had the following problem both times:

No matter what speed I set the CPU to, the machine resets during startup, usually right after the IDE device scan, but sometimes earlier, immediately (1 or 2 video frames) after PNP initialization.

The first part I tried was a mobile K6-2/380. I upgraded the Award BIOS to 1.09b5 (or whatever was the latest) and tried messing with all the settings. I tried removing all the cards, and even activated the on-board VGA, and the symptom never changes.

I returned the mobile part because I though that kind of CPU wasn't right for the board, and later bought a desktop K6-2/400. The symptoms are exactly the same.

What would cause the reset around PCI init time? Can a mis-mapped IRQ cause that (I'm not dumb, it's just that my experience is with Mac!)?

The only weird thing about my board is that when I added USB connectors to the headers on the M/B, a resistor fried and my PS/2 mouse interface no longer works. Perhaps I burned out a power rail that feeds the CPU, but it runs well enough to get through most of the startup.

Whenever I replace the K6/200, everything works fine again.

Thanks a lot to anyone who can help me.

Monte

 

[Guest]

I don't think your mobo is capable of providing the correct voltage for the k6 2 cpu. Mine doesn't, Asus VX97. Have you considered overclocking to get you buy until you can buy a new motherboard?

 

[Crashman]

What voltage, multiplier and bus speed did you use? I have had good success running the k6-2 2.2v version at up to 2.8v with proper cooling! What is the voltage of your old processor?
BTW, if you fried something when you hooked up the USB connector, you probably put it on backwards. You grounded the +5v connector to the chassis.

Cast not thine pearls before the swine

 

[monte]

Thanks for your suggestions.

I just did some tinkering, measuring the voltage at the regulator with a multimeter.

I managed to get 2.1, 2.2 and 2.6-volt settings, and they all behave exactly the same way. This is a 2.2v CPU and the mobile part I had earlier was 2.1. The K6 that works is 2.9.

I have the bus at 66 X 3. I tried 66 X 6 with the new K6-2, and with the mobile part I tried several settings, including slow ones. The behavior never varried, except perhaps that with the mobile part the reset always happened after IDE init, and now it happens there around 85% of the time, and the rest of the time around PNP init.

Regarding the USB connector, I just checked the wiring, and it was assembled correctly. I don't think I ever had it on backwards, but it's possible that I offset it by 1 one time and grounded the PS/2 clock or data.

Thanks,
Monte

 

[74merc]

try the K6 2 @ 200mhz with 2.9 volts, it shouldn't damage it at all, you're well below the temp and wattage specs of the processor.
if it works, something is wrong with the voltage regulator or the jumpers that set the voltage, if you're lucky like me, your motherboard doesn't follow the settings in the manual.

----------------------
Independant thought is good.
It won't hurt for long.

 

[Crashman]

Once in a while I even get stumped by a question. I have never personally had the K6-2 2.2v processor fail to work in a normal system, even at 2.8v! The only system I couldn't set one up on was a Dell, because DELLS were actually MADE to return a BIOS error and lock if anything other than an Intel processor was used!

Cast not thine pearls before the swine

 

[74merc]

It'll happen with old Compaqs as well.
Deskpro 2000 or whatever, they probably bought motherboards from Dell... lol

----------------------
Independant thought is good.
It won't hurt for long.

 

[Crashman]

Dell, I believe, uses a line in bios code that says "get processor information-If it's Intel, continue, if not, quit".

Cast not thine pearls before the swine

 

[BGates2B]

Since you said you can get 2.2, I think your multiplier is off. You mentioned 66X6, but how did you get that? The K6/K6-2/K6III will default to 66X6 if you set the board multiplier at 2X.

If you are sure about the voltage, then I would set the jumpers for a Pentium 133. If that doesn't work, try using 2.8 V like for the P55C chips.