HP 8560E Service Manual page 623

Display/Power Supply Section
Troubleshooting the LCD Display
Dim Display
1. If the display is dim, suspect the backlights, which are inserted into
the LCD assembly from the backlight assembly. Always replace both
backlights at the same time. For the backlight replacement
procedure, see page 158
Troubleshooting using the VGA port
1. Connect a VGA monitor to the rear VGA port of the instrument (the
VGA port is always active and requires no user interaction).
2. Observe the display.
If the display on the VGA monitor is working correctly, the problem
is probably caused by the LCD, or by a cable problem. Proceed to
step 1 in "Troubleshooting using part substitution".
If the display on the VGA monitor shows the same symptom(s) you
have seen on the instrument's LCD, the problem is probably caused
by the A2 controller board, the display driver, or by a cable problem.
Proceed to step 2 in "Troubleshooting using part substitution". If you
proceed past step 3, skip step 4.
Troubleshooting using part substitution
1. Disconnect the power cord, turn the instrument off, and open the left
side. Ensure that W60, W61, W62, W63, and W64 are tight.
Reconnect the power cord and check the instrument to see whether
the problem is corrected. If not, proceed to step 2.
2. Disconnect the power cord and turn the instrument off. Replace
W60, the ribbon cable that connects the A2 board to the display
driver board. Reconnect the power cord and check the display to see
whether the problem is corrected. If not, proceed to step 3.
3. Disconnect the power cord and turn the instrument off. Replace
W61, the 10 MHz reference cable that connects the A2 board to the
display driver board. Reconnect the power cord and check to see
whether the problem is corrected. If not, proceed to step 4.
4. Disconnect the power cord and turn the instrument off. Remove and
replace (see procedure 2A on
board. Reconnect the power cord and check the instrument to see
whether the problem is corrected. If not, proceed to step 5.
5. Remove and replace (see procedure 5 on
board. Check to see whether the problem is corrected. If not, proceed
to step 6.
6. Disconnect the power cord and turn the instrument off. Remove and
replace (see procedure 2A on
power cord and check to see whether the problem is corrected.
622
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page 152) the A17 display driver
page
page 152) the A18 LCD. Reconnect the
172) the A2 controller
Chapter 12