Agilent Technologies 89410A Service Manual page 31

6
Step 6. Check signals required for power up.
a
Remove the top cover.
b Connect a logic probe to A90 TP4 and its ground clip to A90 TP12.
Set the power switch off ( O ) then on ( l ) and check that A90 TP4
c
is a TTL high 10 seconds after power up.
d
If TP4 remains low, the A40 CPU assembly is probably faulty.
Before replacing the assembly, go to
the power supply,'' and do Step 7 to check power supply voltages.
e Set the power switch to off
from A90 P10.
f
Set the power switch to on ( l ).
Troubleshooting the Analyzer
To perform initial verification
page 1-15 ''To troubleshoot
O ) and disconnect the ribbon cable
(
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