Bad motherboard

[Captain Spaulding]

Hi,

Just wanted a 2nd opinion before I tell the customer they have a bad MB:

Symptoms:
Random BSOD's (normally hal.dll ntoskrnl.exe)
Sometimes will power on for 3 secs then switch off
Sometimes the screen freezes completely, only thing possible is to hold the power button
Memtest+ different versions immediately shows errors every time with both RAM sticks in, with only one or the other in, tried both slots, even tried a good RAM stick same thing, a few times it rebooted itself during memtest and also gave the error (unexpected interrupt halting) and froze.

Tried:
Disconnecting everything except PSU, MB, Memory, CPU
Swapped PSU for a new one
Swapped the CPU for a known working one and re-did the paste
Checked caps but they all look good

I suspect its either bad ram slots or MB, can't think of any other tests I can run. The customer did tell me the hovered out the case so maybe they screwed the motherboard when they did it.

I've never seen memtest fail with good RAM before but I guess this points to a motherboard issue.

 

[BrentfromZulu]

Based on what you tried I agree in thinking it is the motherboard. I haven't seen Memtest Fail with good memory, but you had known working memory.

One thing I could possibly think of is perhaps there aren't any spacers or there are spacers everywhere. My first build about 10 years ago I didn't have spacers and it would ground out and not turn on. If that isn't the case I would say Motherboard.

 

[NYJimbo]

In order to gain confidence in your diagnostic of this machine you have to ask yourself what are the possible failure points. Did you replace or diagnose them correctly and remove them from the equation ?

If you are certain that all of the possible failure points OTHER THAN the motherboard have been checked out then it must be the motherboard.

If you really did replace the CPU, PSU and RAM and you say you disconnected everything but those, then it can only be the motherboard.

If the mobo is still in the case it could possibly be the case in contact with the mobo but you should check that out and eliminate that from the diags.

Right now I would go with mobo from what you are reporting.

 

[16k_zx81]

Hi,
Tried:
Disconnecting everything except PSU, MB, Memory, CPU
Swapped PSU for a new one
Swapped the CPU for a known working one and re-did the paste
Checked caps but they all look good

I suspect its either bad ram slots or MB, can't think of any other tests I can run. The customer did tell me the hovered out the case so maybe they screwed the motherboard when they did it.

I've never seen memtest fail with good RAM before but I guess this points to a motherboard issue.

Yep.

................................

 

[B Trevathan]

Yeah, like Jimbo said take it out of the case and have just the necessities plugged in.

I would also reset the BIOS and maybe just for the sake of completeness replace the CMOS battery.

When someone else has messed with it you never know what that have done, they could've shorted something out or they might have shocked an IC chip with ESD and now it is just now starting to fail.

 

[NETWizz]

YEP!

You have done ALL reasonable troubleshooting. In fact, heck... I would have half as much troubleshooting before coming to the same conclusion (only because I am lazy) At this point I would be certain to the point I would personally eat the cost of the replacement motherboard if it didn't resolve the problem.

Here would be my exact steps:

1. Memtest 86+ and two(2) sticks = instant errors.
2. Put 2 x Known Good Sticks in & a Known Good Power Supply (hanging out the side of the case not nicely put in)
3. If there is a newer BIOS flash... do it. Either way reset the CMOS.

If it errors, it is a bad motherboard! If not it is probably bad RAM 95% (could [unlikely] be a bad Power supply... Confirmation would be putting BOTH the other sticks back in and waiting about 5 seconds to see errors)

IF I got errors from bad sticks, I would NOT test them individually. I would just throw them ALL away and completely replace the whole set and button Bertha back up and start Memtest 86+. By the time I finish a sandwich, if there are no errors, I go home and crack a beer.