AN7 Acting Strangely

[craigmcg]

One of my two Abit AN7 XP3200 Setups is acting strangely. Voltages/temperatures seem to be stable but I get blue screens and I'm no longer able to run Prime95. I have swapped out PSUs/CPUs/RAM to no avail. I haven't done a thorough examination of the board yet but I'm wondering if it could be the caps. I haven't seen many reports of bad caps on AN7s- what do you think?

[starfury1]

Re: AN7 Acting Strangely

I don't know the MB or caps used,
from the quick look at google image I cant tell what caps are on the MB apart from electrolytic types

Somewhat older MB by the looks of it

BOSD freezing and reboots are symptoms of badcaps
(and thats not to say it is the fault)

from what you have done sounds like an MB issue
(provided setting are right in cmos I suppose)

so there is a fair chance it might be cap related problem.

Caps most likely to have failed (or failing) are in the VRM section near the CPU and the black things (Mosfets) both sides

I suspect from the photo
4 between mosfets are probably input for VRM
4 in front of coils are most likely output of VRM
its the outputs caps that are most likely failed or failing

I am totally guessing here
most likely and probably 2 types
1500uf ~1000uf (I/P) 3300uf ~2200uf O/P
be some mixture of that I'd guess

probably 6.3 Volt if they are decent caps
10 Volt if they are (probably) crap

So give these good eyeball, BTW caps can fail and show no signs too

if it is the VRM playing up, there could be other causes


quick question, do you OC this thing at all?


Wait a bit and see what the regulars here think

HTH

Cheers

[gdement]

Re: AN7 Acting Strangely

I think all AN7's have rubycon caps. It's the replacement for the NF7-S, and only the first revision NF7's had bad caps on them. Mine has ZL on the input and I think MBZ elsewhere.
Have you tried downclocking anything to narrow down the source of the problem? Is it possible that the CMOS settings got messed up and some voltage is no longer set correctly? In particular I can see that being an issue with overclocker type ram that calls for nonstandard voltages. Also, if that's the kind of ram you have, then I'd try using SPD settings instead of the advertised latencies. But you said you've tried swapping ram so those issues have probably been covered.

Is your chipset fan still working, or is it clogged with dust? The original hsf is really a joke.

I'd try running memtest86, if it passes memtest but fails prime95 then I'd suspect it's a load/power related problem.

[starfury1]

Re: AN7 Acting Strangely

humm if they are Ruby's that reduces the chances of them being failed
(still possible, just not as likely)

Thanks gdement

yeah you are right about those piddly chipset fans they do fail
I think the heat sink may handle it if your not ocing...anyway that the story I believe with my GigiByte and it did fail but was running OK

Cheers

[craigmcg]

Re: AN7 Acting Strangely

Thanks for the replies. The chipset fan failed almost a year back but the temperature readings for the chipset in the bios and using MBM are 36-40C. Memtest 86+ runs for hours without error and none of the voltages seem to fluctuate significantly. I used a Silenx 400 watt PSU until I started having issues then I switched to a Seasonic S12II 550 which improved things but there are still issues. I don't OC and I have run this PC with the CPU undervolted (1.5V instead of 1.65V) for almost two years without issue. I increased the CPU voltage to the normal level with no improvement. I'm almost at the point of replacing the MB

[PCBONEZ]

Re: AN7 Acting Strangely

Remove your memory and put it back - twice.
Unplug and replug all your drive cables. (Power and data, both ends.)
-
Will rub off surface oxidation in contact areas of pins.
.
Also check pins inside both Mobo to PSU connectors for signs of arcing/burning.
Not common but happens.

.

[starfury1]

Re: AN7 Acting Strangely

yeah good point PCbonze...it happens and does cause odd ball behavior

[Fizzycapola]

Re: AN7 Acting Strangely

Maybe the board needs a chipset fan to work properly.

Open the side of the case and point a household fan into it so reported temperatures are 10oC cooler than the ones you posted above, see if it makes any difference to the test results.

[craigmcg]

Re: AN7 Acting Strangely

Hi Guys,

Sorry I haven't replied earlier. I tried the reseating of cables, the RAM had already been swapped at least 4 times, and there was no indication of any arcing in the power connections. Other interesting behaviours have now manifested- the floppy drive is now unable to read known good floppies (disk is not formatted then can't format it) and the CPU fan header no longer works, byt CPU fan works fine in any other header. The chipset fan has now been reconnected (it was noisy and whether or not it was on, the temps only varied by a few degrees) but no improvement. I think the board is dying but could all these strange symptoms be due to caps- do you think it is worth recapping to see if that does solve the issues?

Thanks for all your help so far.

[PCBONEZ]

Re: AN7 Acting Strangely

Yes they could be due to bad caps on the mainboard or in the PSU.

Anything that gets power that's too 'dirty' (noise/ripple) isn't going to work right.
You have to remember the 'power' to things isn't the only concern.
The chips that control things or move data must have clean power too.
[Bad caps can even corrupt data sent to otherwise good drives.]

Lets take your floppy drive:
The 5v to it is working somewhat because it's spinning.
- If the 5v is 'dirty' it may be lousing up the controller on the drive.
- If the power to the floppy controller on the MoBo is dirty the controller may not be sending the right operating signals or may be jumbling the data.

Same same with your fans.
The 'power' is 12v but the controller chips may run off 5v or 3.3v and be mucked up so the 12v isn't getting switched on.

I would suspect bad caps in the power supply first because apparently you board has good quality caps.
- However any cap can 'go'. (Heat makes things worse.)
- Bad caps in the PSU can overwork and overheat otherwise good caps and cause failure.
- Poor ventilation is not a good thing either.

I think you should inspect inside your PSU before you jump on recapping the board.
-
Noise (Ripple) is too fast (frequency) to be picked up by standard voltage checks.
Multi-meters, programs like Prime, or looking in your BIOS only tell you the average DC value and offer zero insight as to how 'clean' the power is.

.

[craigmcg]

Re: AN7 Acting Strangely

I tend to doubt that the issue is power supply since I have swapped out a Silenx 400W for a Seasonic S12II 550W with negligible improvement. The case runs consistently cool as it has both front and rear fans. I keep coming back to the motherboard because I have tried 2 known good PSUs, CPUs, and memory kits. Do you think that the issues could be due to a corrupt bios or are caps more likely?

Thanks for all the help!

[starfury1]

Re: AN7 Acting Strangely

depends on the caps
but yeah blue screen, freezing reboots are some what typical systems of bad caps
you seem to have pretty much ruled out other things
those small chipset fans are junk and do give out.

so yeah MB probably does have an issue

what are the brand of cap and series...on the MB ?

I suppose if you know how to recap and got the gear it probably would hurt to do a recap...at lest that way you know it isn't them...but it could be something else like intermittent dry joint on a chip or component or chipset BGA
and yes there is damage that can happen with memory circuits
caps have been know to cause issues here.


Also Id set bios to "safe defaults" and test (you may have already done this)
(do same after a recap, run it in that mode to be sure every things working)

So yes very possible especially if they are junk caps.

it possible for quality ones to fail too just less likely
depends on use and abuse


Cheers

[djrock]

Re: AN7 Acting Strangely

Hello, It might be too late but I thought I would post since it might help others.

You have possibly damaged the northbridge. The heatsink and fan that is fitted to the AN7 northbridge is not suitable to be ran without a fan! I know this because I own this board and the northbridge fan failed and caused a bsod at startup. It would not recognise the full amount of ram and would not run at 333MHz. I was lucky and it started to work fine again. I changed the northbridge heatsink and fan with a Zalman ZM-NBF47.


djrock

[gdement]

Re: AN7 Acting Strangely

The heatsink and fan that is fitted to the AN7 northbridge is not suitable to be ran without a fan!

True... calling that thing a "heatsink" is generous. It's really just a fan enclosure and a place to put the "ABit" logo. It's hard to see it doing anything as a passive cooler. Not sure if overheating was the issue in this case - he gave modest sounding temperatures above (36-40C) but who knows if it spiked during gaming or whatever.

In any case, anyone running an AN7 or NF7 should proactively replace the chipset cooler - they don't last, and they're pretty pathetic as passive heatsinks.

I was lucky enough to get my AN7 in apparently unused condition from a liquidator, so my original fan worked perfectly. But I swapped it out and am keeping the original in reserve. Not sure what I'll ever use it for, but I can feel warm and fuzzy knowing I have one of the last working AN7 fans.

[craigmcg]

Re: AN7 Acting Strangely

I'm an idiot! While I had swapped hardware and power supplies etc. several times, the one thing I had apparently not done was to clear the CMOS between switching RAM from the 2 new 1GB sticks I had purchased (which by the way ran Memtest 86+ without issue). I had set the machine aside for a few months so I wouldn't throw it out a window- when I reconnected it with 2 512 MB sticks it ran (and is still running) fine although the floppy drive had in fact died. The only thing worse than hardware is software. Thanks for all your help and suggestions.

[gdement]

Re: AN7 Acting Strangely

too bad about the floppy, but glad you got it figured out. It's really a nice board.

[RJARRRPCGP]

Re: AN7 Acting Strangely

With Athlon XPs, I would check the temps. Prime95 failing often means an overheating processor.