After powering up and switch ON my HP 2520, power and alert (!) symbols keep flashing

[AAS2]

My HP printer 2520hc was dead and not powering up. I replaced the controller pcb inside and it started. But after powering up and switch ON, power and alert (!) symbols keep flashing. No sound of any carriage movement during power ON. If I open the cartrige door, the cartridgeg move to the centre and rest. Wat could be the issue?

[Echo_Lake]

@AAS2
Thank you for posting on the HP Support Community.

I have a few troubleshooting steps we could try to fix the issue:  

Firstly, Let's perform a hard reset:

• With the printer turned on, disconnect the power cord from the rear of the printer and also unplug the power cord from the wall outlet.
• Remove USB cable, if present.
• Wait for 2-3 minutes, press and hold the power button on your printer for about 30 seconds to remove any additional charge.
• Now plug back the power cable straight to a wall outlet without any surge protector or an extension cord (This is important) and then plug back the power cord to the printer.
• Turn on the printer and wait till warm-up period finishes and the printer is idle. If the issue persists, I would request you to contact our Support and our Support Engineers should be able to check the available service options for your laptop.
  
  HP Support can be reached by clicking on the following link:
• Click on this link – www.hp.com/contacthp/
• Select the product type.
• Enter the serial number of your device or select let HP detect your product option.
• Select the country from the drop-down.
• You should see the HP support number or Chat option listed

• Please feel free to contact us here anytime you need any further assistance. Please click “Accept as Solution” if you feel my post solved your issue, it will help others find the solution.