ASUS A7V8X-X No Post

[derkraken]

Hello everyone.

I have an ASUS A7V8X-X motherboard. Last night I left the computer on. When I came back to it it appeared to be in sleep mode but wouldn't reactivate.

I turned it off and then tried to reboot and I had no POST beep, although the green power LED was lit, the drives all span and the CPU fan started up. The monitor remained blank with its LED flashing.

I have tried resetting the CMOS, and replacing the CMOS battery. I have tried reseating the Video Card and RAM, and swapping RAM around the slots. Lastly I tried another CPU and while I was doing that I noticed a component near the CPU seems to have blown. Here is a picture of it - one of the square chips with 9915H on it.

Does anyone know what it is, and if replacing it (assuming I can locate another and do so successfully) is likely to revive my motherboard?

Thanks.

[kc8adu]

Re: ASUS A7V8X-X No Post

been there done that.check for bad psu/ram.
thats the vdimm regulator.

[RJARRRPCGP]

Re: ASUS A7V8X-X No Post

Hello everyone.

I have an ASUS A7V8X-X motherboard.

That was my favorite motherboard in 2004,(mine was purchased on November 6, 2003) good for the T'bred 2400+s. (Got my T'bred 2400+ KIXJB in August, 2004) (IIRC, on August 3) It never let me down in 2004 (except for if I get greedy for higher than 180 Mhz FSB, or about that)
(And the max was 160 Mhz FSB for the T'bred 2400+, because I could only use 15.0 for the multiplier)

It always POSTED for me and didn't have too much extras. Those were the days.

Woah, a fried MOSFET!

[derkraken]

Re: ASUS A7V8X-X No Post

Thanks for the replies.

I think possibly the reason for this failure was that I put a stick of 400MHz RAM in along with the two 333 MHz sticks that were already in there. I had FSB set to 333MHz, and I just noticed in the motherboard manual that DDR400 RAM is not supported at 333MHz (only at 266 and 200).

I was running an Athlon XP 2400+ in it, at 13.5x multiplier, 166 FSB.

[c_hegge]

Re: ASUS A7V8X-X No Post

That shouldn't matter. I use DDR400 in DDR266 and 333 motherboards all the time. It never causes problems. DDR400 RAM is fully backward compatible with 333 and 266 motherboards.

[stj]

Re: ASUS A7V8X-X No Post

i think your getting a bit confused,
i have the deluxe version and some similar ones.
the warning is that you cant use all 3 slots if you run faster than 333.
it wont run stable.

it's the same for other motherboards running with a VIA KT400 chipset too.

[ratdude747]

Re: ASUS A7V8X-X No Post

is that like the a7v8x where you can only use 3 slots if you use pc2100, 2 for 2700, and one for 3200?

if so, you have to go by the chip's label, it will not slow the chips down for you.



i just sold my friend one and it took him some time to understand that concept...

[PCBONEZ]

Re: ASUS A7V8X-X No Post

Thanks for the replies.

I think possibly the reason for this failure was that I put a stick of 400MHz RAM in along with the two 333 MHz sticks that were already in there. I had FSB set to 333MHz, and I just noticed in the motherboard manual that DDR400 RAM is not supported at 333MHz (only at 266 and 200).

I was running an Athlon XP 2400+ in it, at 13.5x multiplier, 166 FSB.

As was said, that wouldn't be likely blow the MOSFET.
You pretty much need a short somewhere to blow a MOSFET.
A bad [w/short in] stick of RAM or CPU might do it.
A shorted to ground cap might too.

[Dammon]

Re: ASUS A7V8X-X No Post

The A7V8X-X is a good motherboard. Mine has been running 24/7 since I bought it six years ago and it's showing no sign of any problems. I'm looking at retiring it soon though, since it's really too slow to do much nowadays.

[ratdude747]

Re: ASUS A7V8X-X No Post

have you heard of ubintu or even linux in general? my friend's a7v8x does ubuntu without any problems. granted i loaded it with a tbred 2400+...

[stj]

Re: ASUS A7V8X-X No Post

is that like the a7v8x where you can only use 3 slots if you use pc2100, 2 for 2700, and one for 3200?

if so, you have to go by the chip's label, it will not slow the chips down for you.



i just sold my friend one and it took him some time to understand that concept...

no, it's 3 slots upto and including 333 and 2 slots at 400.

i suspect it's because it's dual-channel so the first 2 sticks are mapped as 64bit.
it's never restricted to 1 slot.

and it's the a7v8x-e deluxe and the a7v8x-x that i have here.

[Dammon]

Re: ASUS A7V8X-X No Post

The A7V8X-X is single channel. According to the manual it can use PC3200 with 2 banks, and PC2700 with a max of 4 banks.

[Dammon]

Re: ASUS A7V8X-X No Post

have you heard of ubintu or even linux in general? my friend's a7v8x does ubuntu without any problems. granted i loaded it with a tbred 2400+...

I'm running mine with a tbred 2200+ and it's fine with WinXP. My biggest complaint is that it can't run HD video without stuttering. I don't think it'd be any different under Linux.

[PCBONEZ]

Re: ASUS A7V8X-X No Post

Correction, Not likely to blow THAT MOSFET.
That one is for main RAM power. [Basically Vcc]

It [too fast of RAM] might blow the Vtt regulator and that might be a MOSFET [vice some other kind of VR] but it would be a much smaller part than the one you circled.

The Vtt regulator being weak is part of why those boards have restrictions on RAM.
Vtt is the logic signal voltage.
- Vtt applied = high = a logic "1"
- Ground [or nearly] applied = low = a logic "0"
The higher the frequency the more load on the Vtt regulator.
.

[Dammon]

Re: ASUS A7V8X-X No Post

Looking at my own board, I notice there's nothing but OST caps around the vdimm regulator. Maybe they've gone bad? The CPU vrm uses Nichicon caps.

[stj]

Re: ASUS A7V8X-X No Post

The A7V8X-X is single channel. According to the manual it can use PC3200 with 2 banks, and PC2700 with a max of 4 banks.

your manual is wrong - so is mine.
the manual does say that, but there are only 3 physical banks on the board!
look at page 1-7

[RJARRRPCGP]

Re: ASUS A7V8X-X No Post

That shouldn't matter. I use DDR400 in DDR266 and 333 motherboards all the time. It never causes problems. DDR400 RAM is fully backward compatible with 333 and 266 motherboards.

Yep, same here. If it fails to boot, you need to raise the latencies, please try 2.5-3-3-7.

DO NOT USE 2.0-2-2-6! (Except that with underclocking, it appears that quality RAM can do this)

[RJARRRPCGP]

Re: ASUS A7V8X-X No Post

I'm running mine with a tbred 2200+ and it's fine with WinXP. My biggest complaint is that it can't run HD video without stuttering. I don't think it'd be any different under Linux.

That may be your video card and I don't recommend having the resolution higher than 1280x1024.
Also, check the video driver setup.

[RJARRRPCGP]

Re: ASUS A7V8X-X No Post

and it's the a7v8x-e deluxe

IIRC, your motherboard is the nForce2 version, the A7N8X-E Deluxe, IIRC, A7V8X-E don't exist.

And the nForce 2 typically gets higher FSBs than the Via KT400, because you don't have the issue with the PCI and AGP going over.

[stj]

Re: ASUS A7V8X-X No Post

could be, not seen it in a while.
i'll try & find it later.