l. Line Voltage Indication and Over Voltage Exposure Interruption Printed
Circuit Board D5. Refer to figures 3-12 and 3-13.
(1) The 15v stabilizer receives its input voltage from the power supply of the
timing switch board D1. The transformer T1 (D5) supplies, via rectifier V1, the voltage
for the Schmitt triggers J1 and J5.
(2) The zener diodes V3 and V4 increase the value of the R-C circuit R8, C3
and R5, C4 smoothes the signal input to the Schmitt, trigger J1.2, J1.6, J5.2.
(3) At a lower control voltage the Schmitt trigger J1.1 and J1.7 (signals) are
at H. via the inverter J3 and the AND gate J4, inverter J3.10 signals L, the light diode V6
(yellow) lights up.
(4) As the control voltage increases the output signal of Schmitt trigger J1.7
changes to L, controlled by R11. The output signal of the inverter J3.10 signals L, the
light diode V6 (yellow) lights up.
(5) As the control voltage increases the output signal of Schmitt trigger J1.7
changes to L, controlled by R11. The output signal of the inverter J3.10 changes from L
(6) The light diode V6 is de-energized J3.12 in turn switches to output from
H to L and the light diode V7 (green) lights up (nominal unit operating condition).
(7) As the control voltage increases further (over voltage condition) the
output signal of J1.1 controlled via R10, switches from H to L.
(8) The output of J3.12 changes from L to H and 3.15 changes from H to L.
The light diode V7 (green) is de-energized and light diode V5 (red) lights up.
(9) At a control voltage, corresponding to a line voltage of approximately
130 v., the output signal of J5.1 controlled via R12, switches from H to L, thus changing
the output signal of J5.7 from L to H.
(10) Transistor V9 conducts, AR 1 energizes thereby interrupts the exposure.
No exposure can be made.