Agilent Technologies 8752C, Руководство по обслуживанию, Страница: 318 / 510

Display T ests
These tests do not return a P ASS/F AIL condition. All six amber front panel
LEDs will turn o if the test passes . The display will be blank; press 4 PRESET 5 to
exit the test. If any of the six LEDs remain on, the test has failed.
59 Disp/cpu com. Checks to conrm that the CPU can communicate with
the A19 GSP board. The CPU writes all zeros , all ones , and then a
walking one pattern to the GSP and reads them back. If the test fails ,
the CPU repeats the walking 1 pattern until 4
PRESET
5 is pressed.
60 DRAM cell. T ests the DRAM on A19 by writing a test pattern to the
DRAM and then verifying that it can be read back.
61 Main VRAM. T ests the VRAM by writing all zeros to one location in
each bank and then writing all ones to one location in each bank.
Finally a walking one pattern is written to one location in each bank.
62 VRAM bank. T ests all the cells in each of the 4 VRAM banks .
63 VRAM/video . V eries that the GSP is able to successfully perform both
write and read shift register transfers . It also checks the video signals
LHSYNC, L VSYNC, and LBLANK to verify that they are active and
toggling.
64 RGB outputs . Conrms that the analog video signals are correct and it
veries their functionality .
65 Inten D A C. V eries that the intensity D A C can be set both low and
high.
10-16 Service K ey Menus and Error Messages