Are display artifacts a symptom of a bad CPU?

[happycomputers]

I have a customer's Compaq laptop: f572us. The reported problem was that it wasn't booting up properly, and was freezing during the bootup.

Upon inspection, I noticed it would freeze at different parts of the bootup: sometimes freeze at the BIOS, sometimes at loading Windows, sometimes after Windows loads...but always within about 3 minutes.

Every time it freezes, the display freezes, mouse hard locks, and display artifacts are present, sometimes totally obscuring whatever was being displayed. Unit remains generally COOL during this period--no signs of overheating.

I tested the RAM, Hard Drive and both test well. To be on the safe side, I've put known-working RAM in and removed the hard drive and the problem remains: still freezing, even randomly at POST, with artifacts.

Ordered exactly the same motherboard, swapped EVERYTHING necessary to boot except for the CPU...problem remains.

Can I safely assume at this point its a CPU issue? Since the machine does not stay responsive long enough, I cannot test it. I've never heard of or seen a CPU cause displayed artifacts on the screen...always assumed it was a motherboard/gpu problem. The only other (long shot) consideration is that I may have received a bad motherboard from eBay, with the same exact problem.

Thank in advance for any help / insight.

(p.s.: disregard cost-effectiveness of this repair. Customer requires this particular model for ... reasons.)

 

[ohio_grad_06]

Think about what you said. Artifacts on display. What part usually displays data on screen? GPU? Especially if that system has an nvidia graphics chip, seems like there were quite a few issues with models that had nvidia graphics a few years back. Might explore that first. If it has to be that computer, check into the cost of a new board. I usually recommend new computer at that point.

 

[Larry Sabo]

Ordered exactly the same motherboard, swapped EVERYTHING necessary to boot except for the CPU...problem remains.

... and the screen. It's likely the GPU but I would try it with a known-good screen, just to be thorough.

 

[NYJimbo]

Are you absolutely sure the laptop is freezing and not the display ? Do you see disk i/o or anything else when its frozen ? If you hook it up to an external video does it freeze there too ?

I've had laptops that had bizarre LCD issues and would "freeze" up either showing weird artifacts or ghosting and it looked like the computer itself was frozen but the display (lcd logic board) was actually the issue.

 

[YeOldeStonecat]

I'm leaning towards the GPU issue.....nVidia graphics. Or could be a motherboard....it's a cheapo model, AMD CPU, from the Vista years. Given the age of it...likely not worth the repair cost.

*Edit*...whoops, disregard, didn't see his fifth line that he swapped mobo. My bad for speed reading.

 

[Markverhyden]

Well, if you swapped the motherboard and the problem persists then it needs to be what left. Which could be the processor or the screen. But I've never seen a screen cause an issue. To be on the safe side you could disconnect the screen and use an external monitor. If you have a similar processor on hand I'd toss it in to see what happens.

 

[happycomputers]

UPDATE: Tested known-working processor, and problem remains.

So I've ruled out RAM, processor, and motherboard (w/ onboard GPU)...got me frustrated and thinking...what hadn't I changed: POWER

Tested power adapter, got good readings off the power tip. Tested modular dc jack (not apart of motherboard) and got wildly fluctuating readings. Turns out this whole time it might be the DC jack. Even though it powers on the laptop; I've read a post about a DC Jack causing artifacts, and so its quite possible. So we'll see. Ordered part, will have in 2-3 days. Will update then.

For reference, the forum post I found: http://www.tomshardware.com/forum/80200-35-toshiba-a205-s4707-artifacts-help-here

 

[MobileTechie]

I'll be interested to see the result of this because 100% of the time I've seen artifacts on Nvidia chipped laptops it's been the GPU. Never seen artifacts from a power socket problem. I await to be amazed!

 

[NYJimbo]

Still haven't heard about results of trying an external display.

 

[happycomputers]

Replacing the motherboard ruled out GPU, in my opinion. With the exception that I received a bad motherboard in, with the same exact problem.

Nonetheless, hooking up an external monitor via VA produces the same problem, identically.

I'm betting on DC jack... That's about all it could be at this point.

 

[Markverhyden]

Replacing the motherboard ruled out GPU, in my opinion. With the exception that I received a bad motherboard in, with the same exact problem.

Nonetheless, hooking up an external monitor via VA produces the same problem, identically.

I'm betting on DC jack... That's about all it could be at this point.

Was the LCD unplugged when you did the external monitor? But I agree that the power plug could be a very possible source. It's not about the artifacts. It's about the machine crashing/freezing.

 

[NYJimbo]

Even though it powers on the laptop; I've read a post about a DC Jack causing artifacts, and so its quite possible.

Does the battery hold a charge ? If so charge the battery, disconnect the charger, boot it and see what happens.

 

[happycomputers]

Does the battery hold a charge ? If so charge the battery, disconnect the charger, boot it and see what happens.

Battery doesn't charge... Boo

 

[Larry Sabo]

Replacing the motherboard ruled out GPU, in my opinion. With the exception that I received a bad motherboard in, with the same exact problem.

My money is on the replacement MB having the same problem--bad GPU. The definitive proof would be to take a known-good MB and swap it in. I cannot imagine a DC jack problem causing interference with the video. Freezing, sure.

 

[KompuKare]

Replacing the motherboard ruled out GPU, in my opinion. With the exception that I received a bad motherboard in, with the same exact problem.

I agree with Larry. Think of it like this:

• A few year old laptop, so any motherboard is most likely used
• The motherboard had a chipset (Nvidia nFarce 6150) which most likely* had an inherent solder defect.
• So at this stage, what are the chances of finding a used motherboard which hasn't died or been baked?

*personally I haven't come across any defective nFarce 6150 chipsets, just 7150 chipset, and 8400GS/8500GS and 8800GT cards. If the 6150 also has a solder defect, this means that Nvidia's problem was not just confined to the 65nm era.

 

[Sterling Archer]

The processor is one component that generally never fails.

 

[mikeroq]

I vote replacement mobo is bad. I've seen many of those nvidia chipped notebooks from that era that fall under the solder issue. Even owned one. Almost all were HP/Compaq.

I really think this customer should replace the laptop but if they want to spend the money sure. I recently replaced a motherboard in a 10 year old laptop. I told him don't get it repaired again. Cost him over $600.

My boss will do almost anything, except tell the customer that its better to buy a new one. I especially tell people with those affected nvidia laptops to not even bother on a repair if it involves graphics/motherboard.

 

[MobileTechie]

I think used motherboards are a shot in the dark these days. There are scores of dodgy people and companies out there repairing dead mobos and reselling them. Quite often their repairs are poor quality or even incomplete. Very easy to end up buying a badly reflowed one or similar.

 

[Markverhyden]

I think used motherboards are a shot in the dark these days. There are scores of dodgy people and companies out there repairing dead mobos and reselling them. Quite often their repairs are poor quality or even incomplete. Very easy to end up buying a badly reflowed one or similar.

Been that way for years. Back in the late '90's it was not unusual to get a refurb'd hd that still had everything on it.

 

[Larry Sabo]

Besides bad GPU, it can be bad video RAM chips, so just reballing the GPU may not fix the problem, depending on the MB. Also, the Northbridge can allow a good external VGA signal while the GPU scrambles the local display on some MBs, so the state of VGA display is not always definitive.