３ INTERNAL CONNECTION
ＭＵＸ-１００ SERVICE MANUAL
３ - ７
ⅴ
T
he signal CHON from the XCONT PCB is required to start control of the inverter.
If the key switch is set to OFF and DR system is turned OFF , CHON and PIC will be available when the
power plug is connected, regardless of the current battery charged voltage.
When the key switch is set to ON or DR system is turned ON, battery charging is prohibited to prevent
the fuse blow because charging current with high frequency will flow into the filter inside DC power
supply (switching regulator) as shown below.
When the key switch is set to ON. >>> The DC power supply PS1 on MUX POWER PCB is
connected to the battery.
When DR system is ON. >>> DC/AC converter PS12 for POWER BOX of DR system
(CXDI-50G) and DC12V power supply PS11 for PC and LCD
are connected to the battery.
(In case of MUX-100/100H, the battery charging doesn’t start if the current battery voltage is high.
As well, the ON/OFF status of the key switch is not related to the charging.)
The green LED LD1 on MUX CHARGE-04A will light on when CHON is available.
Ⅱ
Charging Current Over
ⅰ
When the measured charging current exceeds approximately 3.2A, the error Charging Current Over
is detected by the operation amplifier A5B.
ⅱ
The detection result is sent as the error signal CHBR1 to the XCONT PCB, then charging stops.
３-２-５ Inverter circuit for starter and lamp
Related PCB: MUX CHARGE-04A PCB, INVERTER UNIT PCB and transformer T3
Ⅰ
Explanation
ⅰ
For the starter and the lamp, a common inverter (60 Hz) is mounted on the MUX CHARGE-04A PCB.
ⅱ
The input voltage is the battery voltage (approximately 240V). The pulse width is adjusted, and
converted into the AC with a duty ratio proper to the starter and the lamp.
The pulse width for the starter is adjusted by VR2, and the pulse width for the lamp is adjusted by VR1
on the MUX CHARGE-04A PCB.
ⅲ
The relay K2 changes over the destination of the inverter output between the starter and the lamp.
ⅳ
Though the control signals LAMPON and STON are sent from the XCONT PCB, rigid attention
should be paid because the names do not correspond to the actual contents. LAMPON = Inverter
operation ON signal. STON = Relay K2 changeover signal. While the starter is operating, the
LAMPON signal is ON and the STON signal is OFF. While the lamp is lit, the LAMPON signal is
ON and the STON signal is ON.
ⅴ
Rough explanation of the inverter operation is as follows: The basic frequency of 120 Hz is generated
at CP16 on the MUX CHARGE-04A PCB . The M12 forms the frequency into the pulse width
proper to the starter and the lamp. Because the frequency is as low as approximately 100 Hz, it cannot
goes through the pulse transformer which is isolated the FET. To cope with this, the frequency of 50
Hz is added, and the basic frequency is converted into a waveform which can go through the pulse
transformer.
(Reference) Because the inverter output is as high as 240V and not proper to be supplied to the lamp, it is
reduced to a proper voltage by the transformer T3.
