Black Screen - Presario CQ56

[Denorvan]

Hi,

Hoping to get some advice on a problem with a freinds laptop. 

Started off with my friend asking if I could have a look at why her laptop that was running extremely slow and un-responsive. When I went to look at it the Laptop would not boot up, just powered on, fans and hdd all working but just a black screen. 

I did the unplug from mains, remove battery and hold the power button down method, which helped and it loaded.

The load time was really long, about 25 minutes from boot to actually having all Windows loaded. 

During this time the heat that was coming from it was unbelievable, couldnt put my hand on the keys above the CPU. 

I shut it down and took the laptop home with me so I could have a look at it over the weekend when I had more time, but it wouldnt boot again and holding the power button method no longer worked.  Even tried connecting it to a seperate PC monitor and using Fn + F4 to change to external dispaly.

When the laptop is turned on the Caps Lock Key blinks once every 3-4 seconds, which according to the HP Troubleshooting Guide is a faulty CPU. 

I have stripped the laptop down , reseated the cpu , heat sink with Thermal Paste and cleaned the vents in the fan casing ( it was clogged with thick dust , explains the heating problem ). The CPU doesnt have any signs that it has burned out.

Now when I turn it back on it still has the same problem, light flashing on the Caps Lock Key once every few seconds. The  Fan for the cpu spins ( which now stays cool and I can feel the cool air being blown out ) the HDD spins but still have a black screen. 

I wanted to give as much detail as I could so it makes getting advice easier. Could it just be that the CPU has over heated and needs replacing ?

[AttackofZaq]

Hello Denorvan.  I understand you're working on a notebook which is throwing the "one blink" CAPS LOCK pattern.

It does appear that the CPU needs to be replaced.  You've tried cleaning the cooling system, hard resetting the notebook, applying new thermal paste, and even reseating the CPU with no change.  

What is the product number for the notebook?  I can use this information to locate the parts you'd need to replace as well as some helpful information for repairing the notebook.  This document can show you where the product number is located.

Have a great day and I will keep an eye out for your response.  

[Denorvan]

Hi AttackofZaq.  Thanks for replying. 

The product number inside the battery compartment is

Product : XH200EA#ABU.

Model : CQ56 - 102SA.

Looking forward to your response. 

[AttackofZaq]

Here is a link to your notebook's Maintenance and Service Guide.  This covers how to disassemble the notebook.  

The picture below contains the part numbers for CPUs which were shipped in that notebook's family.



Have a good day!

[Denorvan]

Thankyou for the link but that is not the correct User Manaul for the CQ56. 

http://h10032.www1.hp.com/ctg/Manual/c02657369.pdf is the correct manaul for it.

 It has the AMD chipset Mobo with an AMD V-140 2.3ghz CPU ( Socket S1 so can be replaced independently )

Will let my friend know that it is more than likely her CPU that has failed and she can order a replacement. Once it is installed I'll report back to update this thread and whether or not it fixed the problem.

[AttackofZaq]

Hello again Denorvan.

You are right, that was the wrong guide.  I must have had more than one open.  The guide you link to is the correct one. Thanks for pointing that out!  I have edited my original post to also reflect this information.

Have a wonderful week!

[Marazan]

Don't think this is right. I have the same problem as do many many others (look around the internet). Don't think it's the CPU, Drive, Memory, Motherboard or anything like that. It would appear to be cracked solder, maybe around the GPU. The only way I can get mine to work is to wrap a towel around the vent/fan area until it heats up, has to get quite hot.. Then a forced restart. Obviously the heat expands the solder and the connection is made.  I have read of people replacing all of the above and still have a problem. It sounds more like built in obsolescence to me! HP are well aware of this problem and it's not just on the CQ56, they should come clean and save everyone lots of money through spending on the wrong things. It's really strange how this problem seems to arrive with many just after the warranty runs out. Not impressed. Also, my battery started losing power after 8 months from new, but only now aware there was ever a recall. Nice if HP could inform people about these things, they have all the relevant personal info from registration.