Operating Instructions—7A42
TABLE
2-1
7A42
Belt-Test Failure
Messages
TRIGGER
FUNCTION
(LED
display)
SWITCHING
THRESHOLD
VOLTS
and
crt readout
display
Severity of failure;
functional
usability
of
Instrument
Indication
Test
Indication
Test
CH1,
first
column.
ROM
01
to
04
ROM
Possible
loss
of
front-panel
control;
repair
before
use.
CH2,
first
column.
RAM
05
to
06
RAM
CH3,
first
column
Micro
processor
control
logic.
07
to
09
Micro
processor
control
logic.
CH4,
first
column.
PROBE
OFFSET
10
PROBE
OFFSET
Avoid
use
of
probe
offset
feature. 7A42
otherwise
fully
functional.
Repair
when
convenient.
CH1,
second
column.
Crt
display
and
readout.
11
Crt
trace
display.
Channels
1
through
4
may
not
be
displayable.
Repair
before
use.
12,13
Crt
readout.
Crt
readout may
not
be
functioning.
Cause
could
be
lack
of
mainframe
readout. Repair
when
convenient.
CH2,
second
column.
Trigger
14
Trigger
control.
Some
or
all
trigger
functions
may
not
be
operational.
Repair
before
use.
15
Trigger
logic.
Some
channels
may
not
trigger
properly.
Repair
before
use.
2-51