Troubleshooting The Display; Table 6-6: Troubleshooting The Display - Tektronix TDS2022C Technical Reference

Maintenance
Troubleshooting the
Display
6–30
To troubleshoot a nonfunctional display, follow these steps:
1. Remove the rear case. (See page 6-10, Rear Case.)
2. Turn on the oscilloscope and verify that the display lights up. If it does
not, either the display or power supply is defective. If this procedure is not
conclusive, continue with Troubleshooting the Power Supply. (See page 6-29,
Troubleshooting the Power Supply.)
NOTE. Without a functional display module, the simplest way to verify that the
oscilloscope is on and functioning is to check for a signal at the output. The Probe
Comp output generates approximately a 5 V, 1 kHz square wave.
3. Use the test oscilloscope and the TPP0201 probe to probe the display cable
connector at J201 on the Main board. The following table describes the
signals you should expect to see.
See the exploded diagrams in Replaceable Parts for the location and
orientation of the connector on the Main board.

Table 6-6: Troubleshooting the display

Signal at J201 Description, Color
Pin 1 (marked with ◄) No fixed pattern. Depends on display data.
Pin 2 No fixed pattern. Depends on display data.
Pin 3 No fixed pattern. Depends on display data.
Pin 4 No fixed pattern. Depends on display data.
Pin 5 No fixed pattern. Depends on display data.
Pin 6 No fixed pattern. Depends on display data.
Pin 7 No fixed pattern. Depends on display data.
Pin 8
No fixed pattern. Depends on display data.
Pin 9 26.5 V
Pin 10 Ground
Pin 11 +3.3 V
Pin 12 HI when display active
Pin 13 Data rate clock. 1.36 MHz Square wave
Pin 14 Line rate clock 11.4 kHz, 500 ns high pulse from low baseline
Pin 15 Frame rate clock 43 Hz, 350 ns high pulse from low baseline
Pin 16 Floating
Pin 17 Ground
Pin 18 Ground
1 Value varies with temperature, contrast setting, and display type.
5. If all the signals are present, the display module is probably defective.
Replace it.
1
DC
DC
TDS2000C Series Oscilloscope Service Manual