HP printer p2015 doesn't function - get's stuck during boot with the jam LED on. This status is not listed in the manual. It indicates the formatter board (Q7804-60001) has failed. The formatter board is on the left-hand side - remove the side panel by using a flat screw driver to unclip the panel at the rear of printer. To confirm that the fault is the formatter board there is a button hidden in the frame below the formatter board - pressing this button causes the printer to print a series of straight lines without using the formatter board.
A common method for repairing the formatter board is to bake in the oven to repair dry solder joins:
1) Pre-heat oven to 176degC
2) Place formatter board on some aluminium foil for support, then place onto baking tray with components facing up.
3) Bake for 8 minutes, then remove and allow to cool.
4) Re-connect the formatter board and test printer again.