How can I check the circui board on Global 500 Dishlex?

Dishlex Global 500 series
Machine would run for a short period then switch off before the cycle ends. Pressing a few buttons caused the machine to beep many times. Everthing looks fine on the circuit board as can't see anything burnt. What would cause the machine switch off mid way through cycle? When the power is switched on nothing lights up on the front panel, however the internal light does come on.