Tektronix TLA 720, Service Manual

Page: 43 / 214

Operating Information
2–4
TLA 720 Benchtop Chassis and TLA 7XM Expansion Chassis Service Manual
MONITOR BACKUP
POWER SUPPLY
LOGICAL ADDRESS switches
READY light
ACCESSED light
RS-232C connector
MODID Jumper Selection
Figure 2–4: Rear view of the enhanced monitor
The logical address switches select the logical addresses for the enhanced
monitor. The top switch sets the most-significant digit, the bottom switch sets
the least-significant digit.
The green READY indicator lights after the power-on diagnostics are complete
and there are no failures. During normal operation, the light flashes if there is a
pending error message. Once all error messages have been retrieved, the READY
indicator stops flashing and remains on.
The amber ACCESSED indicator lights when the MODID line is accessed by
the slot 0 device. Refer to Enhanced Monitor Board Jumpers on page 4–23 for
information on the jumper MODID jumper positions.
An auxiliary power connector (MONITOR BACKUP POWER SUPPLY) allows
you to apply +5 V to the enhanced monitor board to provide RS-232 commu-
nication with the enhanced monitor while the mainframe is not powered on. The
jumper located just above the power connector determines whether you source
the +5 V standby voltage from the monitor backup power supply connector or
from the 25-pin connector.
For additional information on the enhanced monitor board jumpers, refer to the
Enhanced Monitor Board Jumpers section on page 4–23.