Laptop hp compaq presario A900 (will not start)

[torquis]

Hello:

You see, I have an HP Compaq Presario A900 laptop, and it won't turn on.

1. I checked the power cable, and it's fine. I measured it with the multimeter and everything is perfect.
2. Even so, I tried another HP power cable with similar characteristics and also, everything is perfect
3. I tried removing the battery, pressing the power button for 20 to 60 seconds to discharge the rest of the electricity and then, without the battery, connecting the power cable, but nothing at all
4. I also tried leaving the battery charging for 30 minutes and nothing.

I don't hear the fan, only the battery charging light turns on and that's it, it doesn't do anything else.

What could it be?

I've read something about reballing, because of the well-known issue with HP Compaq laptops with the NVIDIA chip that unsolder, but I don't know if this video chip has anything to do with the laptop not starting up, or with the fan or with some connector... I don't know

I hope for your help or suggestions.

Best regards.

[whoololon]

From what I understand from your message, it's not that you don't have a video, but that it doesn't start.
My recommendation is that, if you have a lot of affection for it, ask for a quote to repair it at a trusted site, I suspect it may be the motherboard and it may cost around 200 "leros". If that's not the case, remove the hard drive(s) (which in your case are SATA and you can always use them as external ones via USB), and get a new one.
Regarding the reballing, that's fine when you know how to do it yourself, because as a repair, from personal experience, it doesn't last even the three months that the warranty lasts by law.

[torquis]

I thought it was the motherboard, but for that reason, I would like to know if anyone has managed to repair it, I myself have soldered a bios chip several times successfully, and I know something about electronics, the problem of this particular laptop would be more like how do I find out where the fault comes from, if from the bios, from the nvidia chip, from the processor.

For the moment I have ruled out, memory, hard drive and power connection, 3v battery,
I have it disassembled, and I have cleaned it thoroughly, the truth is that it had quite a lot of dirt in the fan heatsink, today I will put it back together again to see if it was something to do with the dirt or a bad contact for this.

But beyond that, I would like to know a method or analysis software of the board if it existed to detect faults in the board, in a way sending electrical pulses and seeing if there is a cut, because although sometimes I use the multimeter for this in terms of current continuity, a board has a lot of work.

I am guided more by the experience of other users and drawing my own conclusions, I hope if someone had something similar happen to me they tell me how they solved it, or some kind of guide, trick or inspiration of what can happen to it.

If the problem were from some component then in a plan transistor or capacitor it would be another thing, because then you have to measure, although I can do this and then make statistics of the most common area where components can fail if near the power supply, near the nvidia chip, etc. etc. that is, a clue in case it happened again, a kind of mapping with the most relevant failures.

Best regards.

[whoololon]

To be more specific, the fault should be found in the power supply module of the board, it is more rare that it is the processor. In my case, an Acer Aspire laptop, what broke was the graphics card (which was not integrated), but it started up normally, however, there was no video signal.
In your case I have been looking, and the new motherboard 462316-001 comes out for about 90 € (HP Compaq Presario A900), if you have decided to do it yourself.

[torquis]

OK, THANK YOU VERY MUCH FOR THE ANSWERS.

Well, you see, I have already solved the problem, there were several.

The first thing was that the fan was full of dust as well as the heatsink.
Then I performed reballing with the graphics, added thermal paste and everything is fine.
It seems that there was a cable that was not well attached or that's what it looked like and I adjusted it.
The capacitors were not bulging at least the most significant ones next to the power supply.
The transistors should not be touched.
General cleaning especially and reballing, or rather reflow since I did not change the soldering.
Then I used a temperature scanning program (argus), because I think that was what was blocking the laptop, among other things.

And ready, everything assembled and working, I have performed several times the restart, shutdown, disconnection with and without battery, and it turns on perfect, and of course, always monitoring the temperature.

I hope that the thermal paste does its job, and in case the temperature increases, then I will drill to the edge and make some holes in the lid with a mesh for this thick dust.

Regards