HP 8753E - Checking A9 CPU Red LED Patterns; Switch Positions on the A9 CPU

A9 CPU Assembly
Normal Mode
Alter Mode
Rocker
Slide
sga c8e
Figure 6-2. Switch Positions on the A9 CPU
Checking A9 CPU Red LED Patterns
The A9 CPU has five red LEDs that can be viewed through a small opening in
the rear panel of the analyzer. (See Figure 6-3.) Four LEDs are easily viewable.
The fifth LED must be viewed by looking to the left at an angle.
1. Cycle the power while observing five red LEDs
Cycle the power on the analyzer and observe the five red LEDs. After an
initial pattern, the five red LEDs on the A9 CPU board should remain off.
n If the LEDs remained off, then proceed to the assembly that you suspect
has a problem.
n If the LEDs did not remain off, switch off the power and remove the
bottom cover for further troubleshooting.
Digital Control Troubloshooting 6-5