Tektronix TDS2022C Service Manual page 91

TDS2000C and TDS1000C-EDU Series Oscilloscope Service Manual
Table 24: Expected signals at J202 (cont.)
Signal at J202 Description
10 FPDATA_34_P 1 Front Panel Scan Data line B No fixed pattern. Stable when
triggered from FPCLR_34_P. Pattern depends on rotation of
knobs being scanned.
11 FPCLR_34_P 2 Front Panel Clock line B 405 kHz. High with 50 ns pulses going
low. Each clock after FPCLR_34_P increments the scan location
by one.
12 FPCLK_34_P 2 Clear Front Panel Scan line B 6.44 kHz. Low pulsing high with
50 ns pulses. Determines beginning of a scan sequence for
second half of front panel.
1
Unused and open on 2-channel models.
2
Unused and tied low on 2-channel models.
11. If all of the signals are present, the Front-Panel board is probably defective.
Replace it.
12. If some or all of the signals are missing, continue with step 13.
13. Turn off the oscilloscope and disconnect the front-panel cable from the Main
board at connector J202.
14. Turn on the oscilloscope and check connector J202 for the same signals as in
step 9.
15. If some or all of the signals are missing, the Main board is probably defective.
Replace it.
Maintenance
79