Tektronix WFM6100 Opt. MB, Руководство по обслуживанию

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General Maintenance
WFM6100, WFM7000, and WFM7100 With Option FP Service Manual
4- 19
Frequencies are shown in the Top Section — read carefully! These tests do not
show a pass/fail result, even if zero. Measurements are relative to the 25 MHz
VGA clock. Refer to Table 4--8 to see the limits for the frequencies.
The Middle section shows pass/fail tests. These are mainly bus tests between
FPGAs, Memory, CPU, etc. Some tests cover busses from an option board to the
Main board. In this case it is difficult to tell which end is at fault. Generally there
will be multiple failures, so the most likely cause is evident. If not, the best path
may be to replace the option card first. If that does not fix the problem then
replace the Main board.
The bottom section of the diagnostics results screen shows bus activity for the
SDI input bus and the display bus from the processor to the FPGA. The SDI bus
activity indicators may not move for some test signals; use 10 bit bars or sweep.
Also, SD inputs only have 10 active bits on the Deserializer bus, while HD has
20 bits. The unit will stay in SD or HD mode, as it was before the ADV
diagnostic mode was initiated.
The last section of the Advanced Diagnostic Screen are the color ramps at the top
and bottom of the screen. These can be used to check the bits provided to the
LCD. If any bits are missing then you will see banding in the ramps. It is normal
to see some bands about
1
/
8
inch (2 mm) wide, especially near the lower
intensity regions of the ramp. This is because the LCD is only 6 bits, so there are
64 steps in the ramp. However, any larger steps or any non--monotonic regions
indicate a problem. Check the cable to the LCD, perform the LCD diagnostic
procedure, or replace the display assembly. It is also possible for the Main board
to cause problems in this area.
Table 4- 8: Advanced diagnostic measurements
Measurement Min Max
VGA Clock 64.4375 MHz 64.4575 MHz
QDR Clock 25.1650 MHz 25.1850 MHz
SD Eye 35.9844 MHz 36.0564 MHz
HD Eye 59.3106 MHz 59.4924 MHz
Audio PLL 1 12.2780 MHz 12.2980 MHz
Audio PLL 2 12.2780 MHz 12.2980 MHz
HSYNC PW 20.4 s 20.8 s
VSYNC PW 18974.9 s 19174.9 s
Lissajous 61.3900 MHz 61.4900 MHz
The advanced diagnostics tests the lissajous data path between the Audio and
Main boards. A failure in this data path can be due to problem on either board.
Isolating Advanced
Diagnostic Lissajous
Errors