Laptop HP Compaq 6720s won’t turn on, won’t power on, there is no display, just a black screen. This is a general diagnostic and repair steps to fix those problems.
Troubleshooting laptop HP Compaq 6720s won’t boot, won’t power on, no display just black screen
When you push on the Power Button the Power led lights ON or NOT, your HP Compaq 6720s won’t start up, and there is no display just a black screen. Possible problem and the fixes steps:
Battery has no charge left with AC adapter failed; you press the power button on laptop HP Compaq 6720s nothing happens, laptop won’t turns on and there is no display, the battery has no charge left, the motherboard doesn’t receive any power, laptop cannot turn on. You plug in the AC adapter but that doesn’t help, your laptop HP Compaq 6720s still won’t power on, there is a chance you have failed AC adapter. In this case try with another charger or check AC adapter with a Multimeter. If it’s failed replace with a new one. (How to check AC adapter with Multimeter).
Power circuit in wrong state or Over volt protection trips; you press the power button but nothing happens, laptop HP Compaq 6720s won’t turns on and there is no display just a black screen (AC adapter is OK), your laptop has static electric charge made Power Circuit in wrong state. Unplug AC adapter, take out the battery and hold down power button for 30 seconds, the static charge will dissipate. Plug in the AC Adapter and turn on your laptop HP Compaq 6720s. This should restore the system to normal operating mode.
Screen faulty or bad video cable connection; laptop HP Compaq 6720s turns on, but screen is black, with Power led lights ON. Test the laptop with an external monitor connected to the HDMI port, VGA port or any Display port, press the appropriate key to switch to it (Fn key + F4 key in most laptop). If the external monitor works fine and load the operation system, most likely you have a faulty screen or bad video cable connection. Check them and replace the faulty one.
Power button failed; When you plus in the AC adapter the charge led lights on, (and there is no static charge), but laptop won’t turn on when you press the power button. Probably you have a Power button failure. Disassemble the laptop and with Multimeter test HP Compaq 6720s power button (ON/OFF) Continuity, if there is no continuity when you push on the power button. The Power button has to be repaired or replaced; you can also try to short the power button borne with conductor wire to see if laptop turns on, (How to Test Power Button).
Hardware failure; the laptop powers on, but there is no display just black screen with Power led lights ON or your laptop HP Compaq 6720s stock on logo or restart. In this case, it’s possible one of the Hardware failed. You can try to disassemble the laptop to bare minimum and try to reseat the hardware one by one and power on the laptop every time you reseat a hardware to know the failed one , replace the faulty hardware,
Some electronics components or chipset on the motherboard failed; Laptop HP Compaq 6720s won’t turn on at all or restart without display, probably you have some electronics components or chipset on the motherboard failed. Disassemble the laptop and take out the motherboard. With a Multimeter check electronics components continuity, Voltage and Chipset temperature, you will need an electronic Schematic Diagram for Laptop HP Compaq 6720s. The failed electronic component has to be replaced, (How to Test Laptop Power System). This model HP Compaq 6720s is known by his card graphic problem if the laptop turns on for seconds without display then restart most likely you have a Graphics Card failure (How to repair laptop graphic card).
BIOS failed; Laptop HP Compaq 6720s won’t turn on at all, if the Power System and electronics components on the motherboard are good, there is chance you have failed BIOS, reprogram or replace the BIOS chip (How to reprogram (Flash). Laptop BIOS).
Motherboard dead. The HP Compaq 6720s motherboard has to be replaced.
For other HP Compaq 6720s problems write a comment.