4 beeps sequence and led light blinking

[Dumisanie]

I have an hp elitedesk 800 G1 SFF, when I plug in the power cable it automatically turns on  and the power supply fan plus the CPU fan spins loudly within a second or 2 then stops and starts beeping 4 times and led light blinking.  What can be the problem ?

[Prométhée]

hi

HP EliteDesk 800 G1 Tower HP EliteDesk 800 G1 Small Form Factor HP EliteDesk 800 G1 Ultra-Slim Desk...

1

Interpreting POST diagnostic front panel LEDs and
audible codes
This section covers the front panel LED codes as well as the audible codes that may occur before or
during POST that do not necessarily have an error code or text message associated with them.

Red Power LED flashes four
times, once every second,
followed by a two second
pause. Beeps stop after fifth
iteration but LEDs continue until
problem is solved.
4 Power failure (power
supply is overloaded).
OR
The incorrect external
power supply adapter is
being used on the USDT.
1. Open the hood and ensure the 4 or 6-wire
power supply cable is seated into the
connector on the system board.
2. Check if a device is causing the problem by
removing ALL attached devices (such as
hard, diskette, or optical drives, and
expansion cards). Power on the system. If
the system enters the POST, then power off
and replace one device at a time and repeat
this procedure until failure occurs. Replace
the device that is causing the failure.
Continue adding devices one at a time to
ensure all devices are functioning properly.
3. Replace the power supply.
4. Replace the system board.
OR
The USDT power supply adapter must be at
135W and use the Smart ID technology before
the system will power up. Replace the power
supply adapter with the HP-supplied USDT power
supply adapter