Agilent Technologies 66000A, Service Manual, Page: 13 / 53

Verification 13
Table 2-1. Problem Symptoms
Symptoms Probable Cause Troubleshooting Procedure
1
Keyboard and modules remain turned off
(fans not ON) Input Line Voltage, check fuse F8 Bias Troubleshooting
Module fans turn ON, front displays
remain blank (Turned OFF) No bias voltages, check fuses F1 &
F2 Bias Troubleshooting
Modules remain OFF, keyboard displays
blinking cursor
¦
Primary Microprocessor (U44)
defective, check fuse F1 ROM & Microprocessor
Troubleshooting
Keyboard displays
Self-test Failed, ROM Checksum Test
ROM (U51) defective ROM & Microprocessor
Troubleshooting
Keyboard displays
Self-test Failed, Internal RAM Test
Primary Microprocessor (U44)
defective ROM & Microprocessor
Troubleshooting
Keyboard displays
Self-test Failed, External RAM Test
RAM (U52) defective ROM & Microprocessor
Troubleshooting
Keyboard displays
Self-test Failed, GPIB Test
GPIB Controller (U17) defective Overall Troubleshooting
Keyboard displays
Self-test Failed, Serial Comm Test
DUART (U91) defective Overall Troubleshooting
Keyboard displays
NO MODULES INSTALLED
Backplane power-up or
communication defective Overall Troubleshooting
2
Keyboard displays
MODULE NOT FUNCTIONING
Module defective or backplane
communication defective Overall Troubleshooting
1
Refer to Chapter 4 of this manual for detailed troubleshooting procedures.
2
Assumes that at least one module has been installed and is connected to the mainframe backplane.