ASUS A7V333 no post

[Spacedye69]

HI!
This board had experienced an oc not post, which normaly you would just reset cmos and re boot. Well, no reboot. I bought a new board and left it sit for a few month. One day I went to mess with it and it posted. WOHOO, I thought. I could re boot it a few times, then it would stop posting. I could take the battery out, let it sit for a few days, maybe have to short the pwr pins for a few seconds, and it would post again. It had gotten worse, now I cant get it to post at all. Its like the bios will not clear when you short the jumpers. The power light on the board lights up, I can get the ps to kick on by flipping the board over and shorting the pins for the ps, and I am getting +3v across the pwr pins. Shouldn't I be getting +5v across the pins? How can you check to see if the cmos chip is bad without swaping chips? I can trace the voltage a few steps past the pwr pins, but then I loose the path. Is there a pin out listing for cmos sockets some where? Also, which part of the vrm would I check to see it it is getting voltage. Any help PLZZZZZ! I've lost my mind!

p.s. I've already done the replace the battery, check with multiple good components, etc.

[999999999]

Re: ASUS A7V333 no post

I had two of those, still have one and a friend has the other. They were fairly picky about memory, the most stable config was a single 256MB in the first or last slot, leaving the middle slot empty.

Another thing to try is removing any AGP video card, clear CMOS, then put in a PCI video card.

This board will not POST (IIRC) if the battery voltage is too low, unlike some boards that will but with loss of presets and clock. Measure your battery voltage even though you'd replaced it before, as now it has been running off the battery if not plugged in.

I doubt the chip is bad, it did post every now and then.

Which part of the VRM did you want to check? At the input, put a probe on L23 inductor's leg (near bottom right corner of the CPU socket). For output, L22's leg, or on the two caps at the very top of the board (some were Rubycon MBZ and others United Chem-Con KZE (green), or if you have sharp needle probes for your multimeter, you can get vcore on the back of the board behind the socket, the middle copper plane and the one right next to it.

I now recall that these boards have a TON of jumpers, check to see if you can find any place one might have fallen off.

You won't get 5V through the pins because you have at least some silicon junctions inbetween the 5VSB and Gnd. 3V should be fine.

Your board has an unusual number of available configurations that don't rely on the bios. If you can decipher them, you might try bumping the vcore by 0.1V, lowering the FSB by 33MHz, and pulling out any extra parts unessential towards getting it to post (leaving 1 memory module, video, CPU, heatsink/fan.

Also in case your PSU's 5VSB rail is weak, set all board USB and/or PS2 jumpers to 5V instead of 5VSB. On mine they read "USB wakeup" and "KBWK" (keyboard wake) instead of 5V/5VSB, which I am suggesting to set to disabled (5V). The other alternative to changing the jumpers would be to just keep all PS2 and USB peripherals (including keyboard) unplugged temporarily, adding back those required to progressively troubleshoot and measuring the 5VSB voltage if so jumpered.

You didn't mention what "check with multiple components" means, we might need to know if we are to assume something doesn't need mentioned, but also to know if it seems like you might have forgotten anything. Did you try another PSU? This board may require a PSU with fairly strong 5V current capability for long term use. A PSU that powers another system, might not cut it with this board particularly if the other system used more 12V current instead of 5V.

If the board is set to jumperfree mode, you might set it to jumper mode, and there is a curious looking switch bank under the AGP slot, maybe for FSB, but it's been so long since I fiddled with one of these boards that I'm not sure. I do recall that the earlier revisions (my example is v1.02) with the United Chem-Con green caps, were not as stable with newer Thorton or Barton CPUs, even at 133MHz FSB and manipulating the multiplier, my other newer revision of same board would overclock same CPUs significantly higher (maybe 200MHz more). Anyway, one thought on this is that you might try temporarily swapping in a slower CPU, and "IF" you get it seemingly stable in that config, if you don't have one of the last bios released then you might consider upgrading that.

There are a bunch of IQ caps scattered all over mine, but none in high current areas, you might inspect them closely but I wouldn't expect them to be a problem.

[Spacedye69]

Re: ASUS A7V333 no post

Thanks for the info! I'll fiddle some more. By different everything, I mean 3 powersupplies, 2 agp video, 2 pci video, 2 cpus 800-100fsb & 1133 133fsb, and counless different memory brands sizes and configs, all drives connected, no drives connected, 2 cpu coolers. I'll try the different jumper configs, but the weird thing I don't understand is, why post 1 minute and not post the next withe the exact same config?

[999999999]

Re: ASUS A7V333 no post

Intermittent posting can happen when it's barely at the threshold for instability. Problem becomes finding the cause, and it is easier to look back in retrospect at the cause unless you know a board is prone to a particular problem but with the two I had still working... the only thing that I recall is it seemed one had a bad battery and I replace that.