Ulvac EGO-40M Instruction Manual page 45

MULTI-HEARTH ELECTRON BEAM SOURCE ～EGO-４０M～
Trouble symptom
1. The filament does not light.
The high voltage is normal.
2. The filament lights, but no beam
current flows. The overload
indicator lights.
Table 6．1 Troubleshooting
Possible cause
A. Filament burnout
B. Poor contact or broken wire of the
filament cable.
C. Short-circuit of the emitter assembly or
filament lead.
(Filament control circuit and protective
fuse burnout.)
D. The fuse for the filament protective
circuit has blown out.
A. Arc discharge in the vacuum chamber.
B. Short-circuit of the high voltage lines to
ground.
Corrective action
a. Change the filament.
a. Check the filaments set-screws for tightness.
b. Check the filament support for contamination. If it is contaminated,
remove it by rubbing.
c. Check the filament terminal for breakage.
d. Check the filament cable connection for tightness. If it is loose, retighten
it.
e. Check the screws on the high voltage feed-through outside the chamber
for tightness.
a. Short-circuit of filament and beam former.
b. Check if metal particles are caught in the filament holder.
c. Check the filament lead for short-circuiting.
d. Check if the specified filament setscrews are used
(Too long screws will cause shorting.)
a. Change the fuse and refer to 1 (C).
b. Failure of EB power supply (See its instruction manual.)
a. Check the filament cables for contamination and insulation film
formation.
b. Check if the gap between the anode plate and beam former is large
enough.
c. Check the insulator surface for contamination. If discharge has occurred,
its trace can be located.
d. Check the high voltage feed-through terminals outside the chamber.
If the high voltage cable insulation sheath has melted, replace the cable.
a. Check if the filament line is shorted to ground.
b. Check if particles of evaporant are caught on the high voltage
feedthrough terminals.
c. Check the high voltage cable for insulation.
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7．TROUBLESHOOTING