Ricoh VT3500, Service Manual

Page: 251 / 330

4. MASTER FEED SECTION
4.1 ADJUSTING THE THERMAL HEAD VOLTAGE
Purpose: To maintain quality when making masters and to extend the
lifetime of the thermal head.
Adjustment Standard: Refer to the voltage value (X) on the thermal head
decal of each machine. The adjustment voltage
should be between "X – 0.1" and "X".
NOTE: This adjustment is always required when the thermal head or
power supply unit is replaced.
1. Turn off the main switch and remove the paper exit cover plate (4 screws).
2. Check the voltage on the thermal head decal. (The voltage varies
according to the individual thermal head.)
3. Turn on the main switch.
4. Confirm that the voltage between pin 22 and pin 18 of CN-503 [A] on the
power supply unit is the correct voltage. Refer to the thermal head decal
of each machine for the maximum voltage value. (0.1 volts less than the
maximum voltage value is also acceptable.)
5. If it is not, adjust VR1 [B].
[B]
[A]
1 December 1993
5-17