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Acer 7720G-Europe has black screen but not dead

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wedgetail:
I am struggling and need to see if I can get my thinking sorted out in general. Since I was visiting Forum for a quick look I have decided to ask a few questions about my problem with a nice Acer 7720G that was bought in Belgium some years ago.

Background:
The pc is a "big" laptop with wide screen and has worked well until apparently the Graphics card failed. Fortunately this is a separate card and the good people at MXM-Upgrade in Belgium added a new HD47650 (found the model in email correspondence), a verified replacement in this pc. My daughter brought it back to Australia recently when visiting and as I also have a 7720G-Travelmate bought here in Australia so that I could give some software support.  

Functionally almost the two pcs the same but hardware have some interesting differences, one being that I can't obviously swap graphics cards, which was an unexpected problem, physically it will fit but orientation is 90 degrees out and the heatsinking will not fit properly.  I have to say I don't think so, it is too different for me to dare a swap.

Problem:
Turning power on, the screen is black and if an external monitor is attached this is black too. The optical drive appears to answer the BIOS (had a PCLinuxOS KDE32 inserted of course, but normally it runs Windows 7 ). If the hard drive is installed this will also try to work, or the HDD activity light will flash. After about 30 seconds activity seems to stop, the cooling fan will turn off.

Accidentally I found that after about 20-30 minutes the system will continuously try to read the CD.

During the shole starting attempt, I never get any beeps as one can expect from starting.

Holding down the F2 key then applying power I would have expected to boot into BIOS setup screen as it does on my 7720G-Travelmate but that does not happen.

I removed Battery, RAM and the HDD module and tried to boot, no beeps. These are easy to remove but since the CD seems to work I did not remove this. Also I did not remove WiFi card or Modem as I was all biased to thinking that the Graphics card was faulty.

I put everything back in having decided that the Graphics card must be the culprit and automatically booted again holding down the F2 key, the system sprang into life with beeps. I found it hard to believe.  However it was not the BIOS screen, it was the Windows not closed down properly screen with options to start, I selected Start Windows as usual.  Everything almost appeared ok, I could login user but the keyboard did not seem to function properly, direction keys and TAB key did not seem to respond.

In a vain hope I thought a re-boot would fix that but I am back at square one, black screen and no beeps.  A this stage I think it must have been a fluke.

At this stage I would like to remove the graphics card and try to boot, hoping that I would get the beeps at least, of course I would not get any error codes as the display device is no rendered in operable.  

Question:
Has anybody any experience removing graphics cards in laptops and try to boot.

Obviously at this stage I had hoped to swap graphics cards between the 7720G-Europe and 7720G-Travelmate but as explained it is not that simple. No winner here.   ;D

Ah yes, I have googled a fair amount on "Acer Black screen" but so far not found a solution.

wedgetail:
I have progress of some sort to tell.  Recording this partly for my own purpose. I seem to struggle with applying proper logic here late in life but have to face up to that.

Two things niggled me, why no beep codes and the keyboard in my opinion was too hot, partly confirmed by comparing my Travelmate 7720G with the Aspire 7720G hot keyboard.  Under normal conditions I believe the left side keyboard area when you place a flat hand lightly touching the keys should just tell you it is a few degrees hotter than the right hand side.  In this case problem case you are in no doubt it is hot not alarmingly so but enough to start thinking about cleaning dust out around the fan air streams.

Since the Aspire 7720G had the MXM card professionally installed I would not doubt that the "filters" were cleaned, those who have ever dismantled the thermal cooling system on laptops knows what the filter is. When I started as the last thing to take the thermal units off the processor and graphics cpu area it was clear my assumption that air passages surely would not be obstructed already, was very false.

Turned out however that there was approximately 1/3 of the length of "filter" severely blocked and thinner blockage in the rest. The blockage was  in the cpu section "filter".  This section is in front of the graphics thermal cooler "filter" section. The result is that both processors has been heat stressed solidly for long periods of time an the components struggled valiantly for extended period and finally succumbed.  

The speed of dust and fiber build up unfortunately for us was no doubt due to re-location of the Aspire 7720G in another room and also not the best distance from a wall.  

The question is how bad is the damage.  I am assuming it is the Intel CPU that has taken the biggest blow, ie no beep codes. I have located a second hand processor in Australia and ordered one, crossing my fingers that the MXM board is ok still for a couple of years. That would be a very nice Christmas present.   ;D

I almost forgot to mention that after cleaning the "filters", which was very easy, I could blow them clear by mouth after removing a big chunk with tweezers, the temperature on the keyboard is now only just detectable by the "hand" test. It is now very acceptable but my hope that the pc would perhaps work has not eventuated.

I seem to remember there was a time when for a desktop, mother board, power supply and CPU was all that one needed to get beep codes. I have not been able yet to test this on a laptop for myself so it is an assumption on my part which I used to determine that the CPU might be worth replacing.

There is also the possibility of putting the suspect processor in my good Travelmate 7720G, I have not been brave enough to do that so far, for one I will/should renew the thermal paste if I do. I have paste but no thermal conductive pads which are used.   For testing the faulty Aspire 7720G I have re-placed neither yet but will at least use new paste on the CPU I am waiting upon to arrive.

This has been a good demonstration of that one should be very attentive cleaning the "air filters" in laptops running at high temperatures will knock the lifetime.  In this case no big loss of data has taken place as the two HDDs could be removed and installed in external USB drive bays. The anxiety and time wasted by a modestly literate pc user probably obvious.

menotu:
The following site has useful info

Repair4Laptop - Do-It-Yourself Laptop & Notebook Upgrading, Modding, Repairing

wedgetail:
menotu
Thank you for the link, I don't remember seeing this one, I am having a look through :).

Addition: Sun, 30 Dec 2012
I have spent some time looking around here, have not found any particular items that gave clear idea.  My related random searches though got me on a slightly different track, and convinced me that removing the graphis card would not mortally disable my machine. So I am heading that way, yanking out the graphics card and then see.

wedgetail:
I obtained another suitable cpu chip off e-bay slightly slower speed. Trying this out however has not changed the situation, still apparently "dead" laptop.  This was the easiest way to check, so now I have the MXM video card and motherboard left. Next step accepting that perhaps the fairly new Graphics card has broken down, so I have ordered of e-bay a less expensive card to prove the one way or other. This will take some time to arrive.

I have obtained manuals and having studied beep codes, I have convinced myself that a faulty Graphics card unlikely to give beep code, there is a big section on error codes, these of course only can show when the display is working. A bit like chicken and egg situation? 

The block diagram of the laptop also shows that sound goes through the graphics card which would explain why there is no beep code when the graphics card fails. 

That raises the question what would happen if the graphics card is removed and trying to start.  This is a situation I have never tried. Are there anyone who has experience with running older laptops with separate graphics cards but having removed this?     ;D

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