Notebook HP Pavilion dv2700. Unsuccessful repair

Question

laptops

Please help in identifying the possible cause of the failure of the HP Pavilion dv2700 laptop.

Terrible diagnosis

It all started with the fact that the girl's laptop stopped loading.
The service center carried out diagnostics and revealed a defect in the soldering of the video chip due to overheating and offered to replace the motherboard.
After diagnostics in the SC, the laptop could be launched, but it was contraindicated to use the capabilities of the graphics system to its fullest.

risky decision

Feeling that replacing the motherboard in the SC will cost almost half the cost of the laptop, I decided to buy and replace the motherboard myself. Also, in order to evaluate the possibility of doing it yourself, I studied the disassembly instructions taken from the HP website, and disassembled and assembled the device, after which it remained operational.
A seller was found on ebay with a good rating and a good price for a refurbished motherboard. This was followed by a victory at the auction and a sea of ​​\u200b\u200bjoy about it.
The parcel went to me from the USA for about 17 days (of which, of course, 10 days it went by our express mail)

Transplant operation

Having received the coveted box, I allocated a free evening for repair work.
Following the instructions clearly, the laptop was disassembled and the motherboard removed.
The cooling system and processor were removed from the old motherboard. All this was installed on the sent board (thanks to the seller for attaching a tube of thermal paste as a bonus). Further assembly went smoothly thanks to the detailed illustrated instructions.

There was no sadness - they pumped up patches

It should be noted that the urgent need to replace the board arose after trying to install the sp1 update package on Windows Vista. As a result, the laptop always had a black glowing screen, which clearly indicated the final breakdown of the graphics subsystem.
After replacing the video card, the image appeared and my joy knew no bounds. But the system wanted to commit suicide to continue updating.
At first, everything seemed to go smoothly, progress was indicated by changing percentages and blinking of the hard drive indicator. Doubts appeared at 44%. After waiting for about an hour, admiring the bluish screen with frozen numbers and the same motionless busy ring, I surrendered to the desire to sleep in silence. Despite the system requirement “do not turn off the computer”, I decided to interrupt its work by long pressing the power, counting on the fact that I would only have to deal with software problems.

FAIL

The next morning, I realized that something was wrong, because the laptop did not want to turn on normally.
After pressing the power button, the fan starts to make noise and the power indicator lights up, but the monitor does not turn on at all. It lasts about 1-2 seconds, then it turns off and on after 2-3 seconds, then the laptop is constantly in the described state.
Still the same sound of the fan , the display turned off and no hint of hdd activity .
Only the power light and touch button panel are lit. The mains power indicator is off , which is rather strange, because the power supply is connected and its plug glows.
Question to the habra community: what could it be?

PS I wrote to the seller of the motherboard about my problem
. PPS The same morning, the screen of my pocketbook 360 broke. This is probably a failcascade.

Answer 1

>Question to the habrasociety: what could it be?
It's like being treated over the phone. But in general, try to disassemble again, check all the connections, cables, contacts - you could just miss something or hurt it during assembly. that at first kept on the snot, and then moved away. It happened to me, but the truth is with the iPhone
It can turn out like a joke: let's go out, go in, it can work

Answer 2

Do not aggravate the situation with self-made repairs! If you are from Moscow, then I recommend the chic service www.notemaster.ru/ (NOT advertising, I share my personal experience). I treated my last laptop there (once the BIOS chip failed due to overheating) and the laptops of my acquaintances / friends too. Purely zhelezyachnik, severe small, easily re-solder chipsets with abdominal contacts, for example. And the prices are reasonable, they do it in a day or two.

Answer 3

In fact, the guys from the SC may have been right in their own way. They have warranty obligations, contracts with manufacturers and in general the work is not dusty. But the only reason to go to the manufacturer's SC is that you have a guarantee. In trouble, it has expired or is missing - it is better to find harsh professionals in sweaters and glasses that will do you not just well, but very well in two days.
Almost the entire series of mobile 8400s is prone to failure as a result of the failure of the video chip (banal overheating). In principle, it is treated by warming up with a good industrial hair dryer (but not for long). If you approach the matter with imagination and skill, the chip is soldered and soldered again using a stencil. If you go quite further, the chip is soldered and a new one is soldered.
Any of these procedures draws a maximum of four thousand rubles. In a good place, not very stunned specialists - 2, 2.5.
But it's an old motherboard. And the symptoms described regarding the new one are more like the dump of the north bridge (the reasons are the same).
In general, fussing with him is almost the same.
For the future, I would recommend modifying the cooling system, inserting a copper plate 0.8 mm thick between the video chip and the heatsink (although I may be mistaken in its necessity). It's just that if there used to be a thermal interface, then one thermal paste will obviously not be enough. And use the laptop only on a flat, cool surface.