Hitachi ZA3000 Series Instruction Manual page 201

Each unused socket should be fitted to the lamp turret by
inserting it between the upper lamp holder plate and the plate
spring.
NOTES: 1. An unused lamp socket should be secured by
fitting it to the receptacle at the top of the lamp
turret. If the lamp socket is not secured properly,
it may snag on another lamp and cause motor
malfunction or break a lamp.
2. The lamp made by Hitachi High-Technologies
should use HLA-4 type.
Since, as for the old products (HLA-3 type etc.),
the lamp code may be caught it cannot be used.
3. The lamp current values stored in this instrument
are those for the hollow cathode lamps made by
Hitachi High-Technologies.
If using the lamps of another manufacturer,
change the lamp current to the values
recommended for them.
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