dv 6700 AMD with Nvidia. Doomed?

[UK Texan]

Hi, first post.

I'm one of many with the above laptop which has failed. Grandson using it, said it just died. I have built many PCs but not done much with LTs.

This has come on after a rebuild. Don't know if I touched on something, or it's just chance. Normally, blue lights come on for half a second and go out. The fan sometimes turns momentarily. The three times it did come on, it went through to boot options. (no HD etc, so it stopped there) Once it was doing that and went off.

I stripped it, and it's one that has red epoxy or some such goo around the Nvidia daughterboard. It makes it very difficult to remove it - this stuff is almost rigid. I imagine it's a fix, or so HP hoped.

Anyway, I can just see the balls of solder/sodder? (The Brits use solder.) These are still spherical, as though they have never run/flowed. I just can't see how they ever thought this would work. I'm told I'm lucky it's survived over 3 years.

Just how probable is it that this is the fault? I'm keeping an open mind. But is there some way I can force the power to stay on? Even power up from another PSU?


Any ideas?

R

 

[MindoverMaster]

The DV6 line is the worst. It is notorious to fail after warranty.

What exactly is your problem? Sounds like your PSU is loose. Might want to re-solder that.

 

[UK Texan]

Because of hearing the bad news about 'reballing' of the Nvidia chip, I kind of assumed that's what it was going to be.

I thought I might measure the voltage at what I assume is the only power input plug - a square 4. Two red, two black - and see if it rises and falls after a second or so. I had wondered if I forced a fixed voltage in there, if it would bypass the "powers good" kind of signal and I could see if the graphics worked, but on reflection, that status-checking might be done on the MB downstream of that plug. I don't know. There is a fair amount of circuitry near the input plug, but I doubt the battery makes any use of that.

I had thought of putting some severe heat into the tiny crack under the video daughterboard, but that's about as sophisticated as putting the MB in the oven - which I'm astonished to hear, some people have had success with.

Sad thing is, it's a darn good computer - until it fails.

 

[C0RR0SIVE]

The gel is to help keep the chip from moving if the solder gets hot enough where it can soften or start to flow again while under use, it's mostly to help keep the chip from moving just enough to cause the joints to crack. Most all BGA chips employ this now due to the solder joints wanting to crack due to the chip wanting to move just a tid bit. If I am not mistaken, the best course of action is to ensure that the system is in fact getting power and that you don't have all those stupid grease pads between the CPU and heatsink. One pad is OK, but HP apparently had a design flaw and decided to, instead of trash all the heatsinks, use several pads between the heatsink and CPU/Chipset. This causes heat build up as it becomes a VERY poor conductor of heat, and insulates it more than anything. I know one of the DV6000's I worked on (forgot the specs) had a space the EXACT thickness of a PENNY between the heatsink and CPU. I actually used a good gob of thermal grease on both sides of a clean penny to make up the space, temps dropped 10C on both the chipset AND CPU. The laptop lasted another 6 months before heat finally killed it.

Common issues with DV6000 line:
Power jack breaking too easily from heat, the solder basically softens due to the current pull
Power PLUG solder joints breaking.
Power plug positive "needle" in the center breaking off into the jack.
Battery/Power circuit failing due to excessive heat.
Chipset (in the earliest models) moving just a bit due to the epoxy not being on the motherboard causing the solder joints to crack
Chipset failure due to heat
CPU failure due to heat (these laptops either didn't have thermal shut-down safetys or had them too high for the solder joints to withstand properly, causing damage)
HDD no longer being seen due to the SATA controller failing (located inside the chipset, tends to fail just before the rest of the chip burns out)

There are several variants of the DV6000 line, using different graphics/processors, but they all have one SERIOUS issue, HP cheeped out on the cooling system and loved the one penny thermal pads over good thermal paste and a few more cents in copper to make up the gap between the heatsink and components. I wouldn't even dare call it a good computer just because of the lack of cooling in them, that is the primary reason they fail, and it's the cause of MANY issues with them.

 

[UK Texan]

Thanks for the replies.

Yes, I was aware of the rubbery pad between the sink and the chip. I've made a block of aluminum and pasted it both sides. I made the block a tad too thick, hoping that the physical pressure would help keep the daughter board against the MB. However, most of the downward force would be from the 4 screws around the CPU, but it did exert a small force.

As I mentioned, on the first throw-together, it worked to boot options and the fan ran well. When I rebuilt it with great care, it wouldn't work. It did start momentarily a couple of times however.

Somehow, it smacks of not being the video issue, but I have no way of telling. Unless there is a major flaw I can easily test, I guess I'm SOL

R