Polyswitches (Resettable Fuses); I/O Power; Table 3-3. Fuse Assignments - Motorola MVME2603-1121A Installation And Use Manual

Block Diagram

Polyswitches (Resettable Fuses)

3

I/O Power

3-20
The MVME2603/2604 base board draws fused +5Vdc, +12Vdc, and
Ð12Vdc power from the VMEbus backplane through connectors P1
and P2. The 3.3Vdc and the core processor voltage power is
supplied by the on-board +5Vdc. The following table lists the fuses
with the voltages they protect.

Table 3-3. Fuse Assignments

Fuse
R28
R30
R34
The MVME2603/2604 base board furnishes +12Vdc and (in
MVME761 I/O mode) Ð12Vdc 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 +5Vdc
power is supplied to the base boardÕs keyboard and mouse
connectors through polyswitch R30 and to the 14-pin combined
LED-mezzanine/remote-reset connector, J1. The
the MVME2603/2604 front panel illuminates when all three
voltages are available.
In MVME712M I/O mode, the yellow DS1 LED on the MVME712M
also signals the availability of +12Vdc 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
Voltage
Ð12Vdc (used on
MVME761 versions)
+5Vdc
+12Vdc
LED (DS5) on
FUS