Technical data

Troubleshooting 4
7000 Series Oscilloscopes Service Guide 79
6 If all cables are properly connected and none of the previous
tests confirm a failure on another assembly, replace the
system board.
To check the 7000A Series display
1 Disconnect the power cord.
2 Check to verify that the backlight inverter cable is connected.
3 Ensure the display LCD cable is connected.
4 Connect the power cord.
5 Use the DMM to check the Inverter Power voltage (see table
below). Refer to Figure 12 on page 75 and Figure 13 on
page 76to locate the test points.
6 If the voltage is incorrect, replace the system board.
7 If the voltage is correct, use an oscilloscope to check the LCD
clock (see table below).
Table 14 Display Signals on the System Board
8 If the clock signal is good, replace the LCD.
9 If the clock signal is absent, replace the system board.
Signal Normal/Typical Result
Inverter Power J2750 Pin 1, 2, or 3 12.4 V
Video Signal J2730 Pin 14 and 15 62.5 MHz clock
7000 service guide.book Page 79 Thursday, October 16, 2008 12:18 PM