Laptop doesn't turn on; irregular internal sound

[chivEd]

Hi

I tried to search for a similar problem in the forum but I could not find anything. the laptop is a compaq Presario 700, my brother bought it like 4 years ago.

when I press the power button (which I need to apply some force to it and press it firmly) the laptop does not turn on anymore. the only thing that happens when I press the power botton is that the green light of the ac adapter from the computer, turns off, and I can hear a fast paced "tic tic tic" sound inside the laptop, and stops only when I disconect the ac adapter ither from the laptop or the power socket.

the only power source I have is the ac adapter which is not the original one that came with the laptop but it has the same specifications. I hope someone can help me and know what the problem is, and if it can be fixed or what? many thanks

 

[fastco]

I would try replacing the power supply first. If you are sure the power supply is good then it could be a short on the notebook motherboard, or just the on/off button could have gone bad.

 

[chivEd]

thanks fastco

so you mean try using a battey, could the problem be a fuse, if laptops have any? and what do you mean that it could be a short on the notebook motherboard?

 

[fastco]

How old is the A/C adapter? That can go bad as well as the on/off switch in the computer. There are no fuses as far as I know. Anything is possible, there are many little components on the motherboard that could have gotten hit with a power surge and shorted out. Start with the easiest thing first, the a/c adapter. Try a different one.

 

[dosboot]

compaq 700

There is a fuse on the board. After removing the base find the spot where the dc jack is. There is a white chip right behind the jack - that is a fuse. It may do the trick. If it does not there should also be a small almost clear chip that says FU on it. That is a fuse bridge, check to see if the metal piece inside looks brown (s/b copper looking) Hope that helps.

 

[lamo]

chived, you have a chort circuit in the MB. try to replace the power board, but, i suspect, it won't helps. if you have multimeter, check the resistance between + and ground in DC jack. if the laptop "ticks" AFTER pressing the power button, the problem may be in secondary power chains. in this case you should check the resistance of power MOSFETs on the power board.

 

[AlbertLionheart]

Unless you are a circuit board engineer, take this to a specialist repair shop. If you are in the UK I can give you a couple of names who will repair for a fixed price.