bed and nozzle heaters are not working at the same time (no replies)

Hello

I modified ramps 1.4 board to use with arduino due as described in due + ramps mod

I can set on and off bed heater or extruder heater one at a time but not at the same time.
when I try second one to set on marlin drops both heaters instantly. Does not matter which one is switched first.

Activated bed PID, tuned extruder and bed PID values but it does not help.
no eeprom on board, so no ex-firmware parameter issue.
thermistors are working and assigned to correct heaters.
tried to extend thermal protection intervals-temperatures but none of tyhem helped.

To test if there is any hardware issues I wrote an arduino sketch and I able to switch on both heaters and read both thermistors. Mosfets are switched ok.
Power supply is sufficient, slight voltage drop from 12.15 V to 11.77 Volts when both heaters are working.

the error messages:
----------------------------------------------------------------------------
Error:Heating failed, system stopped! Heater_ID: 0
[ERROR] Error Heating failed, system stopped! Heater_ID: 0

Error:Printer halted. kill() called!
[ERROR] Error Printer halted. kill() called!
---------------------------------------------------------------------------

So I think there is a marlin config issue I am missing. Atached config files.
If you have any idea please post.

thanks