Agilent Technologies 8719ET Service Manual page 267

8719ET/20ET/22ET
8719ES/20ES/22ES
RF Network Analyzers
Display Tests
These tests do not return a PASS/FAIL condition. All six amber front panel LEDs will turn
off if the analyzer passes. The display will be blank; press
the six LEDs remain on, the analyzer has failed.
Disp/cpu com − Checks to confirm that the CPU can communicate with
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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
DRAM cell − Tests the DRAM on GSP (A19) by writing a test pattern to
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the DRAM and then verifying that it can be read back.
Main VRAM − Tests the VRAM by writing all zeros to one location in each
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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.
VRAM bank − Tests all the cells in each of the 4 VRAM banks.
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VRAM/video − Verifies that the GSP is able to successfully perform both
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write and read shift register transfers. It also checks the video signals
LHSYNC, LVSYNC, and LBLANK to verify that they are active and
toggling.
RGB outputs − Confirms that the analog video signals are correct and it
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verifies their functionality.
Inten DAC − Verifies that the intensity DAC can be set both low and high.
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Test Patterns
Test patterns are used in the factory for adjustments, diagnostics, and troubleshooting, but
most are not used for field service. Test patterns are executed by entering the test number
(62 through 76), then pressing
displayed and the softkey labels blanked. To increment to the next pattern, press softkey 1;
to go back to a previous pattern, press softkey 2. To exit the test pattern and return the
softkey labels, press softkey 8 (bottom softkey). The following is a description of the test
patterns.
Test Pat 1 − Displays an all white screen for verifying the light output of
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the A18 display and checks for color purity.
Test Pat 2-4 − Displays a red, green, and blue pattern for verifying the
63-65
color purity of the display and also the ability to independently control
each color.
Test Pat 5 − Displays an all black screen. This is used to check for stuck
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pixels.
Service Guide
EXECUTE TEST CONTINUE
Service Key Menus and Error Messages
Service Menus - Internal Diagnostics
to exit the test. If any of
Preset
is pressed.
Preset
. The test pattern will be
10- 13