[chadman15]

I'm building a PC, and at the moment it contains nothing more than:
Athlon XP 2600 (w/ 333 MHz FSB)
PC2700 RAM
ATi Radeon 9800 Pro

When I booted it up, it shut off after about two seconds - nothing actually happened, it didn't even attempt to boot, just shut off (but the power light on the mobo [not the case, though] remained on). So I tried the standard tests, clearing the CMOS, adding components one at a time and whatnot, and isolated the problem to the CPU - with the CPU out it works, with it in, it does not work. So I called Asus, and they assured me it was the CPU's fault, not the mobo's. So I RMAd the CPU. Same problem. So I RMAd the mobo, just got it back today, and am still having the same problem (all of this a rather frustrating 2 months after I began). I can find no clue as to what's happening other than that it remains powered on when the CPU is not inserted - and keep in mind I tried this with two separate CPUs. (And I did indeed quadruple-check the A7N8X is compatible with the XP 2600).

This is a serious problem. Can I get some help?

 

[clintfan]

The mobo LED lit is normal, actually a good thing.
Please tell us about your power supply: its brand, model, rating.
And what fans you have attached to what.

-clintfan

 

[chadman15]

The power supply is 400W, 12V (naturally), it meets all the specifications of the motherboard. The brand name is Macron.

Thanks so far!

 

[SPEEDO]

Welcome chadman15..................:winkgrin:

Is this new motherboard going into a new case or a case that you have used before?

 

[chadman15]

New case. BTW, after extensive inspection of the mobo, I just realized that it's the very motherboard I mailed to them. When I mailed it to them, I told them the only conclusion I could reach was that the CPU socket was shorted. Now, they've mailed it back to me, though I at first assumed it was a replacement. Thus the possibility that it's a mobo problem remains, but that would mean they mailed it back unrepaired - and if they did, they're going to get a rather eloquent phone call from me.

 

[clintfan]

Thanks. Assuming it's the MPT-400 I found specs on a review site, they were:
+3.3V : 22A & +5.0V : 35A, 210W; +12 V : 15A , 180W;
-12 V : 0.8A , 9.6W; -5.0V : 0.5A , 2.5W; +5VSB : 3A , 15W
So this supply has plenty of +5VSB to meet the 2A requirement, so that's probably not your problem.

I checked some AMD documents, but got lost... I can't quite make the translation from the voltages and currents available from your supply, to the 1.65V at 42A apparently needed by your XP 2600 processor core on page "23". A bit out of my league there, I guess. Intutively, it seems like a 400W supply ought to be able to do the job, but maybe it just can't quite cut it. It was page "45" that really scared me: so many nanosecond-level requirements for specific power lines coming up and into spec.

FWIW the MPT-400 review said, "...Don't waste any money on this one. It worked good for almost a month. Since then, any system I have put it in develops the mystery hangs." Maybe, as the reviewer suggested, it's just not a very good supply. Trade up to a bigger one, or wait for an Athlon power expert to step up to the plate here. :dead:


About the fans... In your BIOS screens I noticed a setting for how fast your fans need to spin up: "Speed Up/Down Response Time": 1,2,3 or 4 seconds for spin-up. 4 seconds is the default and sounds long, but I assume if they don't come up in time, your mobo won't come up, though it says that's only if you have the "Q-fan" enabled (same screen). You cleared your CMOS-- I don't know what that does to these settings. It also doesn't say which fans need to comply. If it has gotten set back to 1 second, this could be trouble, mostly since right now you can't boot and thus can't enter BIOS setup to fix it!

Hang in there,

-clintfan

 

[chadman15]

Well, I'm sorry to hear that my power supply sucks. :no:

But that doesn't really explain why it works WITHOUT the CPU in place. And if the default BIOS setting is four, then clearing the BIOS should fix that.

Thanks so far, PLEASE help more if you can!

 

[clintfan]

Well the reviewer's supply sucked, but yours might not. We can't really tell from here. But I think it at least sounds like something to try changing. Everybody, everywhere seems to be saying don't skimp on the power supply, get as much juice in there as will fit.

Speaking of juice, the CPU is what sucks most of the juice. So naturally without that load, the supply will hum along fat and happy. But having a mobo that you can't run with a CPU chip in place, isn't really what you'd call working.

Your mobo has all sorts of special power-monitoring/sequencing circuits to make sure everything is kosher before it lets your expensive rig come online. If the supply can't handle the load, the mobo may just be protecting you from the effects of a "brownout", by shutting everything down after a couple seconds.

Hope this helps,

-clintfan

 

[cassandraeidyia]

New case. BTW, after extensive inspection of the mobo, I just realized that it's the very motherboard I mailed to them. When I mailed it to them, I told them the only conclusion I could reach was that the CPU socket was shorted. Now, they've mailed it back to me, though I at first assumed it was a replacement. Thus the possibility that it's a mobo problem remains, but that would mean they mailed it back unrepaired - and if they did, they're going to get a rather eloquent phone call from me.

did you call them and ask them whether its a replacement?
Because i had very strange problems with my p4C800-deluxe,
RMAed it, the new board had the exact same problems...

however i did call them, and they told me that the board was a replacement indeed...(this was through ASUS btw)
however i cannot verify this as i forgot to write down the serial number of the old board..

 

[SPEEDO]

Whenever I had to RMA someones board I would take a rectangular file and just file a tiny notch on the edge of the board somewhere just to make sure it wasn't the same one I got back.

Usually if the send you the same board back they will tell you that it's been repaired although I really can't see them spending the time messing about repairing these things.

 

[andykarr]

I had what *sounds* like a similar problem a couple of years ago, and for me it was indeed the power supply.