Acer 6935G - Desperately out of ideas!

Having a major issue with this laptop just randomly switching itself off.

Spec:
Acer Aspire 6935G
Intel T9400 ES (Engineering Sample)
2x 2048MB Memory

The laptop works okay for every-day use like web browsing, watching movies etc. but will sometimes switch off randomly, and guaranteed to do so if I'm stressing it in any way.

Within 30 seconds of running Prime95 (64bit) it will die, the same happens if I boot up stresslinux from CD and run CPU burn from command line (both 64bit and 32bit editions).

I thought it was due to the Engineering Sample CPU so switched to a standard Intel P8800, same thing again! And the CPU temps are low when this happens... under 40 degrees Celsius. (Laptop is clean as a whistle as well, no dust)

I've tried running just on the battery, just on the power adapter, with either memory sticks... I still get the same problem. Despite low CPU temps, as soon as I run Prime95 the computer is off.

The only thing I think it could be is the Northbridge, the thermal pad on it got a bit messy so I replaced it with the same thermal paste I used on the CPU and GPU (it's unbranded stuff). But would it really overheat and switch off THAT quickly?

Any help much appreciated.

 

Make sure the power adapter matches the power requirement label under the laptop.
If you use a low power adapter on a laptop with higher power requirements you risk damaging the laptop as well.

 

Thanks, the power adapter is the original Acer one which came with it, the problem is also present when just using battery power.

 

Use HWmonitor to check the temps.

 

Yeah I have like I said, all my temps are around 35-40oC and no higher. Laptop is running very cool.

Should note that Prime95 switches off now within 5 seconds of running, nothing has a chance to get hot before my system dies.

 

have you ever heard that some core 2 duo CPU has stucked CPU temp??
my CPU have the STUCK CPU temp.....
on HWmonitor it always show 40C and below even after few hours of gaming.....

 

@jai554: Possibly. ES CPUs are especially prone to having wrong temperature readings.

 

The ES has no heat sensors at all, but like I said I switched to a standard P8800 which reports sensors fine.

The issue isn't with heat, I can put my hand on the heatsink and it's very cool. The problem occurs instantly once Prime95 or another CPU burn-in program is used.

 

Is your MXM card original, or a replacement? If replacement, it may have power requirements in excess of what the 6935G can provide.

 

The MXM card is the original, the laptop shipped with a P7350 so I've upgraded that twice to a T9400 ES and now a P8800. I've tried underwatting the CPU as well to no avail.

The other trouble I had was with the power, it kept flicking on and off rapidly and I had to fiddle with the connector to get it to stay on. I took it apart and replaced the DC jack which had come loose, I also replaced the power supply for good measure.

Could permanent damage have been done to the motherboard when the laptop was in this state?

 

Also probably worth noting I can push the CPU usage to 100% with WinRAR for a long period of time and get no problems what so ever.

 

What mode are you using Prime95 in? AFAIK it also puts stress on your RAM in Blend mode, which could be faulty.

 

All modes on Prime95 give me the same result

Also get crashing with Intel Burn Test within Windows.

From bootable memory diagnostic tools, both Windows Memory Diagnostic and MemTest 86+ crash at random times.

Could it be memory? I not entire sure the computer would just switch off, would expect BSOD followed by a reset.

 

Unlikely to be memory, but the extra power consumption from the memory load might be pushing the system over its power limits.

However, I'm starting to lean towards faulty power distribution components on the MB. Or perhaps the NB needs a reflow (chip losing contact with MB due to thermal dilation).

 

Thanks for your replies, I think I've worked it out now after looking at the motherboard components a bit closer like you said.

I have heat readings for all my sensors open and one of them, TZ00, which is Northbridge I think, is getting really hot really quickly. It seems to get to exactly 106oC then my systems dies. I've ran this a few times (just compressing files) and everytime it does the same

I believe I actually removed a thermal conductive pad from the Northbridge heatsink and replaced it with thermal paste, which clearly isn't adequate. I'll have to pop down the local computer shop and buy a pad tomorrow and see if that fixes it.

 

Lol, yeah the gap on the NB is HUGE, need a pad for it. Unless you want to be fancy and use a copper plate ofc. A pad is easier and more than enough though.

 

I've had the same exact issue with my Acer Aspire 7741G.

I don't think it's an overheating issue at all.

From what I've noticed on my end it actually seems to be a power supply issue. If I turn on my laptop from cold (like first time turning it on in the morning) without the Power Adapter in, it will run perfectly fine from 100 all the way to 0% regardless of how much I'm running it.

When I plug in the power cord, the adapter itself gets overly hot pretty quickly. Sometimes I can use my computer all day no problems, sometimes it will shut off every 5 minutes, it's totally random.

I switched over to another power cord, and it's been working fine for the week. Not sure if this is a panacea trick in my head and I've been getting lucky but that's my own strange theory as to why I've been getting these random shutdowns. Not a computer expert by any means, but I don't think the brick Acer sent me with the laptop actually has enough juice to power this laptop or the adapter itself is overloading (explains how it gets scorching hot sometimes)

 

If his NB is getting to 106C then I can say that is his issue.

Did your machine come with a 120W brick? If its 90W you can get a 120W acer one to be sure.

 

Yeah it's a 90W brick. The replacement I've borrowed this week has been a 120W.

How would I get a 120W brick for it? Acers website with spare parts that you can buy only lists a 90W thats compatible for this model. Guess I'll have to give CS a call and see what they can do.

 

That it is! I actually thought the heatsink was a lot more flush than that. The original pad was damaged so I had to put something there.

This was driving me mad, I even hit the laptop a few times... hope no damage is done. Should be able to grab a pad tomorrow and check if that fixes it.

Any advice on cleaning the Northbridge chip? All the transistors make me a little nervous.

 

90W and 120W bricks (say for the 7738G) are the same connector.

Just wipe the chip clean with some soft tissue.

As long as the NB has some cooling it wont get too hot. That's why the cooling system is not too worried about it.

 

Excellent mate thanks

 

Hmm I'm using a Acer 6920G which is similar to the Acer 6935G and long since replaced the NB thermal pad with AS thermal paste. Accidentally ripped the pad first time i popped the laptop's cherry But it's been working fine ever since no cooling issues whatsoever. This does makes me wonder...