1) No anode current when working

Reasons: a. grid resistance open circuit.

       b. transforming switch of anode and grid broken.

       c. high voltage direct current not reaching anode of electron tube.

       d. AC contactor contacting point broken, transformer not electrified.

       e. high-frequency forming switch broken.

2) Anode current too large when no-loading.

Reasons: a. strike fire phenomenon happens in resonant cavity.

       b. strike fire phenomenon happens in capacitor.

       c. electric conduction area of resonant cavity and resonant cavity or  electric conduction area and machine touching.

       d. top of resonant cavity and resonant cavity not good touching.

       e. capacitor beside electron tube filament open circuit.

       f. capacitor of grid fusing.

3) AC contactor jumping when working.

Reasons: a. bridge high voltage commutator broken.

       b. high voltage capacitor 500P/ 15KV of high voltage direct current system broken.

       c. electron tube interelectrode open circuit.

       d. high voltage transformer short circuit.