Motorola MVME2600 用户手册
3-18
Computer Group Literature Center Web Site
Functional Description
3
Polyswitches (Resettable Fuses)
The MVME2603/2604 base board draws fused +5V DC, +12V DC, and
–12V DC power from the VMEbus backplane through connectors P1 and
P2. The 3.3V DC and the core processor voltage power is supplied by the
on-board +5Vdc. The following table lists the fuses with the voltages they
protect.
–12V DC power from the VMEbus backplane through connectors P1 and
P2. The 3.3V DC and the core processor voltage power is supplied by the
on-board +5Vdc. The following table lists the fuses with the voltages they
protect.
I/O Power
The MVME2603/2604 base board furnishes +12V DC and (in MVME761
I/O mode) –12V DC power to the transition module through polyswitches
(resettable fuses) R34 and R28 respectively. These voltage sources power
the serial port drivers and any LAN transceivers connected to the transition
module. Fused +5V DC power is supplied to the base board’s keyboard
and mouse connectors through polyswitch R30 and to the 14-pin combined
LED-mezzanine/remote-reset connector, J1. The
I/O mode) –12V DC power to the transition module through polyswitches
(resettable fuses) R34 and R28 respectively. These voltage sources power
the serial port drivers and any LAN transceivers connected to the transition
module. Fused +5V DC power is supplied to the base board’s keyboard
and mouse connectors through polyswitch R30 and to the 14-pin combined
LED-mezzanine/remote-reset connector, J1. The
FUS
LED (DS5) on the
MVME2603/2604 front panel illuminates when all three voltages are
available.
available.
In MVME712M I/O mode, the yellow DS1 LED on the MVME712M also
signals the availability of +12V DC LAN power, indicating in turn that
polyswitch R34 is good. If the Ethernet transceiver fails to operate, check
polyswitch R34.
signals the availability of +12V DC LAN power, indicating in turn that
polyswitch R34 is good. If the Ethernet transceiver fails to operate, check
polyswitch R34.
In MVME712M I/O mode, the MVME2603/2604 supplies SCSI
terminator power through a 1A fuse (F1) located on the P2 adapter board.
If the fuse is blown, the SCSI device(s) may function erratically or not at
all. With the P2 adapter board cabled to a transition module and with an
SCSI bus connected to the transition module, the green
terminator power through a 1A fuse (F1) located on the P2 adapter board.
If the fuse is blown, the SCSI device(s) may function erratically or not at
all. With the P2 adapter board cabled to a transition module and with an
SCSI bus connected to the transition module, the green
SCSI
LED on the
Table 3-3. Fuse Assignments
Fuse
Voltage
R28
–12V DC (used on
MVME761 versions)
R30
+5V DC
R34
+12V DC