I have a 3035 3K on meter the exposure lamp will not come on. I went through the TS procedures. Switched out the lamp, inverter PCB,scanner PCB, main PCB, and the riboncable on go. Checked power source input to main all good. Only odd reading is CN1-3 has no voltage it should have 5VDC and 0VDC whin lamp is on. Any thing else to do. HELP!!!!!