K8N no boot....

[DixiePenguin]

Re: K8N no boot....

Hi, Stevo,
I would recommend using something besides a Dell PS. They went through a phase of altering the standard atx plug wiring in order to further force customers to rely on Dell repairs and parts. There was an article on the web a year or so back. There were some instances of fried mainboard and/or PS damage as a result. I think they have stopped but I'm still reluctant to use them.

Actually, on a basic no frills test ( cpu. ram, and video), a very low power supply will work. I usually use a 250 watt to test even on P4 system(if it has the necessary connectors). You do need to replace at least the one known bad cap. A single baddie will prevent boot, I have found this repeatedly. Fortunately for me, though not the original owner, they tendency is to pitch the board without even trying the repair. This has provided me with a number of very nice boards once crap caps have been yanked and replaced. Asus boards are good when they work but can be a nightmare to diagnose and repair.

Motherboards also have instances where they fry one of the tiny block resistors, making it nearly impossible to locate the problem much less repair it.

Hope this helps

[DixiePenguin]

Re: K8N no boot....

SOrry,
Trying to make sense while half asleep and missed the post that you had given up. I would keep the cpu and try in another board. I have several that came off boards that were completely shot but cpu survived and worked great on different mainboard.

Enough, time to try to sleep.

[stevo1210]

Re: K8N no boot....

I sat down today and had a small thought about the PSU that was powering the system when it died... a Powmax. All voltages were in spec. But I was wondering if that thing that everyone talks so much could be it. The thing I am talking about is ripple current. If there is too much ripple current will that kill electonic components as well??

In this case the motherboard and or CPU because every other component in that PC works fine (Graphics, RAM etc.).
I have since recapped that Raidmax PSU and I am currently using it inside a Pentium III 800EB system.

Only annoying thing is that everytime I switch it on, I get a loud buzz through my radio.... most likely because they didn't install any EMI reducing components in there.

But when I compared this Raidmax to a DEER I'd have to say they did a better job than DEER. They did a good job, but it wasn't as good as my Delta PSUs.
The DEER has abosolutely no MOVs around the primary caps and also the primary caps in the DEER is only 470uf compared to 680uf here in the Raidmax. Secondary caps for the 3.3V and 5V lines also have higher capacitances of 2200uf compared to only 1000uf in a DEER.

So can ripple current really kill a whole motherboard??

Thanks.

[i4004]

Re: K8N no boot....

don't think so. if the psu output cap is in such a bad condition you'll sooner have psus's protection kicking in to shut it down.

badcaps ON THE MOBO can cause mobo destruction indeed.
or badcaps in psu, but not output caps.

powmax? raidmax? which one did blow your mobo?
what make were the caps in it?

[stevo1210]

Re: K8N no boot....

don't think so. if the psu output cap is in such a bad condition you'll sooner have psus's protection kicking in to shut it down.

badcaps ON THE MOBO can cause mobo destruction indeed.
or badcaps in psu, but not output caps.

powmax? raidmax? which one did blow your mobo?
what make were the caps in it?

The PSU that I suspect blew my motherboard was the Raidmax that was powering it. I suspect because the voltages were all in spec when measured with a DMM. +5VSB was 4.90V, 12V was 11.98V, 5V was 4.8-4.9V and 3.3V was 3.2V .
The caps in the PSU were JEE and United. I found bad caps in there when I opened it after the K8N failed to boot. The bad capas were a JEE 1000uf 10V that was connected to 5VSB. The other bad cap was right next to the blown JEE on the 5VSB line and was 47uf 6.3V.... that cap was also JEE brand, but it blew it's can as well.

Thanks.

[i4004]

Re: K8N no boot....

to assess capability of that +5vstb supply to damage the board we would need the image that shows it(and marked caps that were blown).
older designs lack any protection, new designs are better.

but given that after the incident psu still had voltages ok it seems more likely it was mobos fault.

but real hard to say in such case where it can be either of the two...real hard to say who's guiltier, so to say...

if the psu has better +5vstb design i would say it was mobo to blame, because +5vstb output would also be protected.

[i4004]

Re: K8N no boot....

story jonny just told here
https://www.badcaps.net/forum/showpo...6&postcount=36
bares some resemblance to your case, i think, so in the end this rises the chances the psu was responsible for slow and steady destruction of that mobo.

we're left wondering how much would mobo's life be prolonged if it had better quality caps on all places.

so yeah, ripple kills but not in a way i originally thought happened (i thought this was a case of sudden death...but bulging caps on mobo suggest it wasn't).
it's more of a slow death.

[zandrax]

Re: K8N no boot....

@ stevo: a multimeter or your mobo hardware monitor can't detect ripple, your values are average ones. So your Raidmax could have killed your mobo without any previous sign.

Zandrax

[i4004]

Re: K8N no boot....

if psu is producing excessive ripple it just means caps on the mobo have to work harder to smooth out the voltage and they're loaded more than usual.
this means no sudden death.

[zandrax]

Re: K8N no boot....

this means no sudden death.

I mean the previous owner couldn't have noticed this or been able to track the problem down to the power supply: the computer may had been slightly instabile (occasional reboots, system crashes, freezes and so on) but there are dozen of plausible causes for this, both software (drivers, program conflicts, ...) and hardware (overheating, faulty ram, faulty hardware in general) ones.
Owners of emachine pcs didn't realize their machine were doomed until bestec psus killed their motherboards through their famous killer 5V: this one, however, was a slow degradation that begun with first boot but went unnoticed and eventually appeared as a sudden damage.

Zandrax