３ INTERNAL CONNECTION
ＭＵＸ-１００ SERVICE MANUAL ３ - ９
３-２-7 Power ON/OFF circuit for DR system
Related PCB: Power 100D PCB and Link Assy
Ⅰ
Power Supply for Power 100D PCB
ⅰ DC24V is input to the connector JCNT of Power 100D PCB from XCONT PCB when the key switch
is set to ON and XCONT PCB is working.
ⅱ DC5V is obtained as output of the regulator M7 from DC24V.
Power 100D PCB starts function with this DC5V power supply.
Ⅱ
ON operation of DR system
ⅰ When the switch “DR” is pressed, the operation signal is input to PC1A through the connector JSW1 of
Power 100D PCB. Then, M1A generates high level pulse for 2.5 sec.
There is no input signal from the connector JUSB because PC is not ON for this moment.
As a result, M4A③ becomes high level for 2.5 sec.
ⅱ M4B⑥ also becomes high level if DC24V input is available from XCONT PCB through JCNT.
As a result, the output of M1B also becomes high level for 6 sec.
This signal is input to M3, then the relays K1,K2,K3 turn ON.
ⅲ As K1 turns ON, the relays K21 and K22 of Link Assy also turn ON. (K21 and K22 are connected to
the connector JK21.)
As a result, the battery voltage is supplied to PS11 (DC 12V power supply for PC and LCD) and PS12
(DC/AC inverter for CANON Power Box) ,then the power of DR system becomes ON.
At the same time, M6 generates DC24V since the battery voltage is supplied through J240.
As well, the fan ,which is located near from PC and is connected to JFN ,starts working.
ⅳ As K2 turns ON, the contact of JEXT is closed.
This signal goes to JEXT on MUX CHARGE-04A, then goes to XCONT PCB.
Finally, it reaches to NEXSC PCB, then CPU can recognize that DR system is ON.
ⅴ As K3 turns ON, LED in the switch “DR” lights ON.
ⅵ LED5 on Power 100D PCB lights ON.
ⅶ If PC becomes ON within 2.5 sec. after the switch “DR” is pressed , DC5V is input from USB
port of PC through the connector JUSB, then M5B⑥ becomes high level.
As a result, the input of M3 is still at high level even after M1B⑤ returns to low level.
Namely, the power of DR system is kept on ON condition.
If the key switch of MUX-100D is set to OFF, DC24V is not supplied from XCONT PCB.
However, DC24V still exists as the output of DC power supply M6 because J240 is connected
to the battery.
As well, DC5V also still exists as the output of the regulator M7.
So, Power 100D PCB can continue working.
Namely, DR system can keep ON condition even if the key switch is set to OFF under ON
condition of DR system.
Ⅲ
OFF operation of DR system
When PC is shut down by SHUT DOWN operation from DR system, DC5V from USB port
of PC disappears, then the input signal to M3 becomes low level.
As a result, all of K1,K2,K3 on Power 100D PCB and also K21,K22 of Link Assy turn off,
then power supply for DR system is shut down.
At the same time, the power supply to J240 also disappears, then Power 100D PCB stops
working.
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