General Maintenance
6. If the backligh
t is not on, check the backlight power cable from the backlight
inverter (on the rear of the display assembly) to the main board J18. Also
check connector J18 itself for any solder issues.
7. If the backlight is still bad, replace the front panel assembly – although there
is still a small chance the problem is in the main board.
Audio Power-Up
Diagnostic Failure
It is someti
mes difficult to isolate the root cause of audio problems. Most audio
problems are due to faults on the audio board, but the audio board communicates
with the main board, so in some cases the problem may be there as well.
Audio Power-Up Diagnostic Detailed Information. The Power-up Diagnostic does
the following:
Reads all of the AES decoder internal registers and verifies that what is read
is correct
Reads all of the D/A internal registers and veri fies that what w as read is correct
Performs an active-bit test on the A/D output clocks
Checks the serial EEPROM to see which of the analog inputs have been
calibrated
Tests the Audio DSP/FPGA interface
The main CPU detects if the DSP heartbeat fails. This condition will be
shown in the diagnostic log
For a udio boards, not all errors are reported by the power up diagnostics.
Therefore, if you are d etecting a loss in a udio functionality, check the diagnostic
log for any reported audio errors. If any errors are found, perform the following
procedure to narrow the problem to either the audio board, the main board, or
the connection between them.
1. Prepare a test oscilloscope with the following settings:
Control Setting
Vertical Scale 2.00 V/div
Horizontal Scale 5.00 µs/div
WFM6120, WFM7020, and WFM7120 Waveform Monitors Service Manual 4–17
To Next Page
Loading...
Need help?
General
