Laptop hp cq62 not start, black screen. after pluging ac cord he start itself, and after that, it is impossible turn it of.

This may not be the ac adapter itself. the metal prongs on the side of your HP Laptop to connect to the wire of your ac adapter may be bent or shortciruited. try to get a replacement which may be hard depending on what type of HP Laptop you own. or you may just have to send it back if you dont know how, in order to avoid breaking the warranty policy by mistakenly damaging it.

Need to check the connection of the LCD to the motherboard.

http://h10032.www1.hp.com/ctg/Manual/c02641795.pdf
Start on page 70 and follow exact instructions

Shane, new power cord? Does this mean the old one was bad?

Do I assume you used a multimeter;
1) To test the voltage output of the AC adapter (Charger),

2) And had an assistant gently wiggle the cable TO laptop, and power cord TO AC adapter; to see if there was an intermittent reading on the multimeter?

[The Center Hole on the plug end of the AC adapter cable TO laptop, is the Positive connection. The outer cylindrical metal shell of the plug, is the Negative connection.
You should be reading 18.5 Volts DC.

An economical multimeter can be purchased for as little as $5 to $12. Available in a multitude of stores. An auto parts store is but one example. I have seen them on the checkout aisle racks, of large discount stores.

The Positive (Red) probe lead is inserted into the multimeter, in the Red hole that has DC Voltage next to it. (DCV)
The Negative (Black) probe lead is inserted into the Black hole ( - )

The Function knob is set to DC Voltage. If just a symbol, the symbol is a dotted line over a solid line.
IF there is more than one DC Voltage scale, the Function knob is set to the 0 - 50 Volt scale. { 0 to 50 ]

AC adapter checks OK?
Then check the DC Power Jack.
The DC Power Jack is the jack on the laptop, that the cable from the AC adapter is plugged into. (DC_IN)

AC adapter removed, ('Natch), and Battery.
Use a No.2 pencil, and it's eraser, to see if you can gently move the Center Pin, in the DC Power Jack.
ANY perceptible movement means replacing the DC Power Jack.

However good news. The DC Power Jack is NOT soldered directly to the motherboard.
It is a DC Power Jack that has wires coming from it, and the wires end in a small white plug.
This assembly is called a DC Power Harness,

All you have to do is partially disassemble the laptop, unplug the DC Power Harness plug from the motherboard, and replace,

http://www.amazon.com/Harness-COMPAQ-Presario-Pavilion-Series/dp/B004SFQA7U

USE AN ESD wrist strap, and connect it's alligator clip to a good ground source.
I connect to an unpainted surface, of the metal frame of an open, empty desktop computer case.

You can also set a large metal serving plate (Unpainted), on the table you are working on, and connect to it.
Or a large metal knicknack. (Unpainted)

Use a mutli-compartment container for the various screws you will remove.
Label each compartment for the area the screw/s come out of.
SOME screws look VERY similar to other screws.
Advise do NOT mix them up.

http://www.insidemylaptop.com/hp-g62-compaq-presario-cq62-disassembly/

(Just so you have it in case you need it for the future,

http://www.insidemylaptop.com/replace-lcd-screen-hp-g62-compaq-presario-cq62-laptop/ )

HP Support > Compaq Presario CQ62 series of Notebook PC's > Manuals > Service Manual, (Free),

http://h10025.www1.hp.com/ewfrf/wc/manualCategory?cc=us&dlc=en&lang=en&lc=en&product=4188484&

Click on the first file listed -
Compaq Presario CQ62 Notebook PC and HP G62 Notebook PC -
Maintenance and Service Guide

This is a PDF file. The computer you are using now has Adobe Reader on it, which uses PDF files.
After you click on the above file name it may take up to 30 seconds, before the first page comes up.
(The file is downloading in the background)

AC adapter checks out, DC Power Jack checks out?
Check the Power On switch.

The Power On switch is pressed with the Power On Button.
The Power On switch is part of the Power Board,

http://www.ebay.com/itm/HP-G62-Compaq-CQ62-G56-Power-Button-Board-4EAX1PB0000-DA0AX1PB6E0-595204-001-/120845794823?pt=LH_DefaultDomain_0&hash=item1c22f87e07

This part separates the user from the tech. There are 6 wires in that flat cable. (I believe 6) There are 6 contact pins in the motherboard connector, for those 6 wires. TWO of those contact pins turn the laptop on. A tiny flat tipped Jewelers screwdriver, is used to MOMENTARILY touch the two contact pins.

{The Power On switch is a Momentary Contact Switch }

Laptop comes on you have a bad Power Board.

Laptop does not come on;

One or more Power MOSFETs may be bad, and may include bad Ceramic Capacitors (MLCC) for the Power MOSFETs.
Information using HP Pavilion dv6000 series, and Pavilion dv9000 series Notebook PC's as an example,

http://mayohardware.blogspot.com/2010/04/important-parts-on-dv6000-and-dv9000.html

Yes, motherboard replacement

For additional questions, or to have me clarify anything I have stated, please post in a Comment.

Regards,
joecoolvette

When you plug in the power cord is there any lightswhatsoever on the laptop, where the plug goes in or on the AC Adapter of thepower cord?

When you press the power button do you hear fans running, hard drive spinning,lights on the computer, hear any beeps or lights constantly blinking, hear theDvD/CD drive click and the light on the drawer of the DvD/CD turn on for asecond or two? If so the laptop is trying to boot or may have booted, butthe screen is not showing for some reason.

Beep tones and blinking lights tells the technicians what is going on with thelaptop and why it is not booting. Most times it's a motherboard issuewhen you hear beeps or blinking lights continuous.

Maybe your power cord is bad if you don't get anything to happen whatsoeverwhen you press the power button. And if that's true maybe you wasoperating off the battery the last time you had it on and since the power cordis bad, it was not charging the battery so the battery is drained and the powercord is bad.

Maybe you have a Static Charge Buildup. Remove the Power Cord, Remove theBattery, then Press and Hold the power button for 30seconds. After 30 seconds plug the power cord back in (leave the batteryout) and hit the power button to see if it boots. If it does, you can putthe battery back in and let it charge.Maybe your DC Power Jack which is where the power cord plugsinto the computer is bad. Take an ink pen and push the tip inside thejack and see if the little pin wiggles, if so the jack is bad. You'll have totake the laptop apart to fix it. Most times it is soldered onto themotherboard, so you will have to desolder the old and solder a new one.

Hi,


Im very sorry to hear that, please follow these simple steps for you to be able to isolate the exact problem.


1. Removed the battery.
2. Connect the laptop directly to the power outlet without using the battery just for the meantime.
3. Turn on the laptop. If the laptop is able to power on, that means that the AC adapter is working fine as well as the DC port. If the laptop is not able to turn on, it maybe the AC adapter itself or the DC port.
4. Try to use another AC adapter if possible, make sure that that AC adapter is working fine. If the laptop is still not turning on, the problem is with the DC port itself. In that case, you will need to replaced the Motherboard itself.


Hope this will help...Thank you for using Fixya...

I suggest you start diagnosing by using an external monitor, if available.
A VGA monitor.

(It can be a VGA monitor that looks like a small TV, {CRT}, or an LCD flat screen that has a VGA cable attached.
More information on VGA connectors,

http://en.wikipedia.org/wiki/VGA_connector

Laptop off, and VGA monitor off, connect the VGA cable of the monitor to the Left side of the laptop.
(Rear top port)

Turn the monitor on, and then the laptop.
Do you see a display on the external monitor? (VGA monitor)

No?
Press, and hold down on the Fn key (Function Key), and tap once on the F4 key.

A) If BOTH the external monitor screen, and the laptop screen have the same pinkish display, the problem is the graphics chip. (More on graphics chip in a moment)

B) If just the laptop screen is pinkish, and the external monitor graphics are okay, the problem is inside the laptop display.

1) Could be a loose connection of the Display Panel Cable.
{The Display Panel Cable attaches to the motherboard, and the LCD screen in the laptop display}

2) Could be a bad Display Panel Cable.
Possible damage to the Display Panel Cable is the the laptop display was open.

Look for signs of damage to the sheath of the Display Panel cable.
However the damage may not be apparent. The Display Panel Cable could have been stretched.
(Laptop display open when dropped)
The tiny wires inside the Display Panel Cable could have become damaged.

Testing requires that the Display Panel Cable be removed.
A multimeter is used to check continuity of each wire.

{Multimeter function knob is set to Ohms. 1K or 10K if these settings are available.
The Positive probe lead (Red) is touched to a wire at one end of the Display Panel Cable.
The Negative probe lead (Black) is touched to the other end of the wire.

Analog multimeter needle swings up, you have continuity. Don't worry about the Ohm reading at this point. As long as the needle moves.

No movement? Have a helper gently move the Display Panel Cable around.
See if there is continuity shown, or is intermittently shown.
Indicates a break in the wire.
Solution is to replace the Display Panel Cable.

Same with a digital multimeter. No reading, or intermittent reading indicates a broken wire.

Display Cable Kit - HP Part Number 595196-001
I have seen several listings on the internet.

3) Could be a bad LCD screen.

Check the connections.
Check the display panel cable
If this checks out okay suspect the LCD screen.

Compaq Presario CQ62-238dx Notebook PC - Service Manual,
(Free from HP Support),

http://h10025.www1.hp.com/ewfrf/wc/manualCategory?cc=us&dlc=en&lang=en&lc=en&product=4252487&

Left-click on -
Compaq Presario CQ62 Notebook PC and HP G62 Notebook PC - Maintenance and Service Guide

This is a PDF file. (The computer you are using now has Adobe Reader on it, which uses PDF files)
It may take up to 30 seconds before the first page comes up.
It may also take additional time for the file to fully download.

In the Bookmarks menu on the left, click on the + sign to the left of Removal and replacement procedures.
Now click on the + sign to the left of Preliminary replacement requirements, then go on to Component replacement procedures

For additional questions post in a Comment.

Regards,
joecoolvette

first remove battery and try to turn on with ac adapter pluged in.

then without power to the board, alternate sticks of ram to see if one is bad.

also you may want to remove the internal wireless card and see if it was causing a problem.

finally if you have access to a volt meter check the health of the ac adapter and the connection on the back of the laptop where the laptop makes contact with the battery to charge it. if it is not out putting power then you most likely have either a bad dc jack or a bad motherboard.

Most likely one of your ram sticks went bad try taking each out one at a time.

you get a black screen right, nothing at all then no bios, no logo, nothing at all?
Do you get any beep codes and if so in what order?
did you try different ram?
First try to plug your laptop to an external monitor. If it works, you screen is bad, if it doesn't you probably need a new motherboard.

Your inverter to the lcd screen might have went bad.

Here is one I found on ebay!

http://cgi.ebay.com/Acer-Aspire-5100-5610-5650-5680-LCD-Inverter-Board_W0QQitemZ170175860594QQihZ007QQcategoryZ3666QQssPageNameZWDVWQQrdZ1QQcmdZViewItem