General Maintenance
1. Prepare a test o
scilloscope with the following settings:
a. Horizontal Scale 5.00 μs/div
b. Vertical Scale 2.00 V/div
2. If the diagnostic log contains an entry that reads Fail Audio DSP Self Test
fpga,do the following substeps:
a. Check the FPGA programmed indicator (DS0820 on the audio board). If
this LED is off, skip to next step; otherwise probe pin 34 of connector
J750 of the main board during the boot sequence. If the signal on the pin
toggles, r
eplace the main board; otherwise, probe pin 34 o f J200 on the
audio board. If the signal toggles on pin 34, replace the cable; otherwise,
replace the audio board.
b. Probe pin 33 of J750 on the main board during the boot sequence. If the
signal does not exhibit a low-to-high transition, replace the main board. If
the signal does transition, check pin 33 of J200 on the audio board. If the
signal does not toggle on pin 33, replace the cable.
c. Probe pins 31 and 32 of connector J750 during the boot sequence. If the
signal on either of these pins does not toggle, replace the main board. If
both signals do toggle, probe pins 31 and 32 o n the audio board. If the
signa
l does not toggle on either pin, suspect the cable.
d. Probe pin 30 of J200 on the audio board during the boot sequence. If the
sign
al does not exhibit a low-to-high transition, replace the audio board.
If the signal does transition, check p in 30 of connector J750 on the m ain
board. If the signal on pin 30 does not toggle, suspect the cable; if the
signal on pin 30 does toggle, suspect the audio board.
e. If all signals in a through d are correct replace the audio board.
4–18 WVR6020, WVR7020, and WVR7120 Waveform Rasterizers Service Manual
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