If the fuses are broken, the front panel LEDs will turn orange. Then the fuses need to be replaced. Occasionally, the front panel LEDs look normal but still the digitizer gives no valid trigger. This is also an indication of broken fuses. To verify this, go to the digitizer window and click on the diagnostics button, if you see all counters go all 0s to all bits on and loop over this process then the fuses need to be replaced. Because this is an indication of electrical problem.