Agilent Technologies Ininiium 9000 Especificaciones descargar pdf (Pagina 98)

Chapter 5: Troubleshooting

To check the backlight inverter voltages

The backlight inverter board is accessed by opening the front chassis as described in the “Replacing

Assemblies” chapter. Below is a picture showing what the inverter board looks like (this picture is of

the back of the front chassis - the display is on the other side of this piece).

• There is an input connector at one side of the board.

• There are two output connectors on the other end of the board, that power the two backlights which

are inserted into the flat panel display.

The output voltage is approximately 300-450 V

rms

, 40 kHz (measured differentially between the two

wires) when the backlight is illuminated. The voltage is approximately 1 kV before the backlight tube

is illuminated. A red LED on the backlight inverter board illuminates when the output voltage is present.

When the backlight goes off (when the oscilloscope’s operating system switches to screen saver mode)

the voltage on pins 1 and 2 (with respect to ground) slowly decays to 0 V.

The outputs are controlled by the input. Notice that input pin 5 goes low to enable the output voltage.

These pins can be reached at J1 on the display board MP12.

Table 5-6

Backlight Inverter Board Input Voltages

Input Pin

7 65432 1

Backlight

OFF

0 V 0 V0 V0 V0 V0 V0 V

Backlight

5 V 0 V 2.5

0 V 0 V 12 V 12 V

This is the backlight inverter

board

1 2 ... 93 94 95 96 97 98 99 100 101 102 103 ... 165 166

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Agilent Technologies Ininiium 9000 Especificaciones Pagina 98