Fostex G16 - Page 14

Q5 and Q7 are mounted on the Regulator PCB. Rl ~ R3 are mounted on the Tension Pod
PCB.
3 .1.4 Power Supply for Motors (Refer to circuit diagram for System Control and Regulator)
Power consumption is reduced by varying voltage and current supplied to the reel and capstan
motors using the repeated ON/OFF action on the Regulator PCB Q2 and Q3.
When current to the motor becomes 5 ~ 6 amperes, Q4 and QI switches on which in turn,
switches on Q2 and Q3 to raise voltage to the motor. Q2 and Q3 will also switch on when the
signal from the System Control PCB (J9-1) goes to LOW. When Q2 and Q3 are switched off,
a low voltage will be supplied to the motor through DI. Q2 and Q3 will switch on at the start
of PLAY mode and during F.FWD/RWD mode.
3.2 Controller (Refer to circuit diagram for Controller)
CPU UI on the Controller PCB has two main functions. One is in lighting the LED ’ s on the
Controller (except for the bargraph LED meter and “ NR OFF ” LED) by receiving serial data
from System Control.
The other is to check ON/OFF of the Controller switches and to send this data to System
Control in reply to its request.
3.2.1 Dynamic Scan
1) LED
LED ’ s (except for the bargraph LED meter and “ NR OFF ” LED) are lit by dynamic
scan.
LOW or HIGH level is output to each segment LED of SEGMENT E 0 ~ 7 and SEGMENT
I 0 ~ 7 depending on which segment is to be lit. On the other hand, the digits are lit (by
HIGH output) in order ofl-*2-*.... _ *12- > l _ *2-*....~ > 12 _> l-*2->....
LED ’ s of digit off (LOW) will not be lit regardless to whether the segments are HIGH or
LOW.
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