Dropped Dv7 will not post

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Sparrow_69

Gawd
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Jan 20, 2004
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A good friend of mine asked me for some help regarding her older dv7 laptop (Q9000, 4gb, 4650)The notebook was dropped on the floor and the screen cracked. I connected an external display and proceeded to boot up the system. All the lights on keyboard come on, fan can be heard and the HP logo is displayed on external screen. Unfortunately the system shuts itself off after 20s. There are no led error codes and system does not post.

I've tried removing hard drive, battery, hard reset, resetting ram/replacing ram. All this results in same result: shuts off after 20s and no bios post. Once (and only once) was I able to get into the diagnostics screen to run some tests (after resetting the ram) but again system shut off within 20 seconds. Also tried booting holding down win key and B key (which from what I understand loads a previous bios). When I tried this I get blinking leds (3x) which should indicate a problem with ram, but there is no image output to screen or post/boot. I also believe the hard drive is shot from the fall (not recognized in bios on another laptop)

Is there anything else I can try? I was really hoping I could at least get the system working with an external screen. The fact that video was being output to an external screen gave me a glimmer of hope. If there was a problem with the motherboard itself, would I even get any video output? Internal screen also works (although shattered)

Thanks :)
 
My guess would be that maybe the heatpipe is no longer making solid contact with the cpu or gpu (or thermal pad if so equipped), or it has broken open and no longer able to transfer heat away from those chips. See if maybe reseating the heatsink with fresh paste or thermal pads helps any.
 
I completely disassembled the laptop and inspected the heatsink. Seems fine, nothing obviously wrong though 1 screw seemed loose. Replaced thermal compound and reassembled laptop. Notebook now asks if I want to run diagnostics when I boot up (correctly recognizes that there is no hd in place) but still shuts off after about 20s.

I did however notice the fan does NOT turn on at all when the machine is switched on. Granted, its only on for a short period, but wouldn't the fan normally at least be spinning when the is first switched on and is sitting at the diagnostics screen? I was sure it ran yesterday, but it could have just been my other laptop nearby. I will likely disassemble the notebook (again) and test the fan with an external power supply to see if it runs. Any idea what the fan specs are? According to service manual I need part number 516876-001.

thanks
 
I was able to briefly access the bios. There is an option to always have the fan running (which is set to on) but fan definitely doesn't run. Also under diagnostics, only error returned is no hard drive. For sh*** and giggles, I tried spraying compressed air onto the fan while the laptop was running. Figured this might either :A)keep the temps in check temporarily B) allow fan to report to mobo that its actually spinning. Needless to say this didn't work. I guess it could be that the fan is completely shot and not reporting anything..
 
The CPU is generally worked pretty hard when booting. Seems like the fan is dead and that the processor might be overheating as a result.
 
^ yep. that explains why it runs for 20 seconds before it shuts off. replace the fan!
 
Fan/heatsink looks fine. Replaced thermal compound and reassembled. Unfortunately, still same problem -> shuts off after certain amount of time. First boot up lasted about 90s, 2nd time about 40s & displayed some graphical corruption on external screen, 3rd boot up about 30s. Still seems as though its heat related. I'm guessing the gpu cooling is to blame because of the graphical corruption on 2nd boot. There is only 1 heatpipe that runs from the copper plate covering gpu to heatsink, so its possible that it is no longer functional (though I didn't see anything wrong with it) Sigh...

At this point I'm wondering if its worth spending more time messing around with it. Seems that a new cooling assembly goes for about 40$ on ebay. I did consider rigging up a frankenstein cooling system from desktop cpu heatsinks just to test it out. Hmmmm...
 
Sparrow_69 said:
Fan/heatsink looks fine. Replaced thermal compound and reassembled. Unfortunately, still same problem -> shuts off after certain amount of time. First boot up lasted about 90s, 2nd time about 40s & displayed some graphical corruption on external screen, 3rd boot up about 30s. Still seems as though its heat related. I'm guessing the gpu cooling is to blame because of the graphical corruption on 2nd boot. There is only 1 heatpipe that runs from the copper plate covering gpu to heatsink, so its possible that it is no longer functional (though I didn't see anything wrong with it) Sigh...

At this point I'm wondering if its worth spending more time messing around with it. Seems that a new cooling assembly goes for about 40$ on ebay. I did consider rigging up a frankenstein cooling system from desktop cpu heatsinks just to test it out. Hmmmm...
Click to expand...

There's a wicking material lining the inside of the heatpipe. It's somewhat fragile, so a hard enough hit could cause a section of it to break away from the wall of the heatpipe. That would seriously compromise the heatpipe's ability to transfer heat. See if holding the laptop up so that the heatsink is above the heat source helps keep it on longer.
 
ryan_975 said:
There's a wicking material lining the inside of the heatpipe. It's somewhat fragile, so a hard enough hit could cause a section of it to break away from the wall of the heatpipe. That would seriously compromise the heatpipe's ability to transfer heat. See if holding the laptop up so that the heatsink is above the heat source helps keep it on longer.
Click to expand...

No difference. First boot -> 90s. Second boot->40s. Here's an image of the cooler. The gpu is on the right with the single heatpipe. Assuming the heatpipe/cooler is the problem, would the gpu heat up to the point of shutting down (within 90s) just sitting in the bios? I'd think the cooler is still somewhat transferring...

 
I should add that the fan does indeed work. First time i disassembled/reassembled, I mistakenly didn't push the fan connector all the way in. I fixed that mistake 2nd time I took apart the laptop.
 
With the board out, have you noticed any bulging or blown capacitors? Anything loose that's connected to the board? How do the memory sticks look? Is everything seated tight?
 
txsizzler said:
With the board out, have you noticed any bulging or blown capacitors? Anything loose that's connected to the board? How do the memory sticks look? Is everything seated tight?
Click to expand...

I've thoroughly inspected everything. Even asked an electrician to take a look with me and we could see nothing wrong. I'm thinking heat is the issue, but could a problem with the board me the culprit? The fact that subsequent reboots shut down significantly quicker than first boot just screams heat problem though..
 
Microscopic solder cracks which inhibit conducting once the chips get hotter? I'm not an electrician, but if all else fails I'd bust out the heat gun and heat up the chipset and/or other BGA mounted elements. Just lose the heatsinks and paste, and also use some aluminum foil to mask off adjacent elements.
Or just apply some pressure onto the heatsinks.
Just a thought, good luck.
 
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