HP 4395A - Page 223

TROUBLESHOOT THE A51 GSP and A52 LCD
Use this procedure when the LCD(Liquid Crystal Display) is unacceptable, or not being bright.
1. Run the Internal Test 3: A51 GSP.
The A51 GSP can be checked using the internal test 3: A51 GSP, if the test fails, the 4
Ch 1
5 and
4
Ch 2
5 LEDs blink several time and a few beeps sound at the end of the test. Then the analyzer
returns the control settings to the power-on default setting values.
a.
Press 4
PRESET
5 , 4
SYSTEM
5 ,
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
SERVICE MENU ,
NNNNNNNNNNNNNNNNN
TESTS , 4
3
5 , 4
x1
5 ,
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
EXECUTE TEST to run the
internal test 3. When this test starts, 4
Ch 1
5 LED and 4
Ch 2
5 LED are turned o.
b. Check the 4
Ch 1
5 and 4
Ch 2
5 LEDs and the beeps at the end of the test.
If no beep sound and the LEDs don't blink, the A51 GSP is probably working. Continue
with the next Check the Two LEDs on A51 GSP.
If a beep sounds and the LEDs blink one time, the A51 GSP chip is faulty. Replace the
A51 GSP.
If two beep sound and the LED blinks two time, the A51 GSP's DRAM is faulty. Replace
the A51 GSP.
If three beep sound and the LED blinks three time
, the A51 GSP's VRAM is faulty.
Replace the A51 GSP.
2. Check the A52 LCD(Liquid Crystal Display)
The A52 LCD can be tested using the internal test 70 to 74.
a.
Press 4
PRESET
5 , 4
SYSTEM
5 ,
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
SERVICE MENU ,
NNNNNNNNNNNNNNNNN
TESTS , 4
7
5 , 4
0
5 , 4
x1
5 ,
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
EXECUTE TEST
NNNNNNNNNNNNNNNNNNNNNNNNNN
CONTINUE to
run the internal test 70, and run the other tests with the same manner
.
b. If any defects on the LCD, replace the LCD.
c. If no correct patterns are displayed, check the A54 Inverter
.
Digital Control Troubleshooting 8-11