Fails when connecting heater cartridge

[Tinchus2009]

Hello. I have an old smoothoeboard, verson 1 may be?
Iwas working ok but a heater cartridge failed last week. I though the heater cartridge failed so I replaced it but the new one didnt worked. First thing I did was removing and disconecting the cartridge, turned upside down my printer and check the board, all lights looked ok. I turned on the heater and I can see the oboard led (big mosfet q7 I think it is called) ON. I checked the voltage and I can read 12.5 V there.

Soi I connect the new heater cartridge, turn on everything again. LED on the board is on, but I checked voltage on the conector and now there is no voltage there.

So my guess there is some problem on the board?

May be this component is wrong?

Please help me