IBM System 9000 Troubleshooting And Servicing page 28

2 . 7 CRT D I SPLAY PROBLEMS
CRT disp lay probl ems are revealed through distorted , faulty, or miss ing
video . These problems may be caused by faults in the CRT display un it ,
in the interconnecting cab l e , in the planar board, in the power supply,
or in the printer/plotter control board.
environment may be respon s ib l e for some display problems a l s o .
This chart l ists pos s ib le CRT display problems , ident ifies one o r more
CRUs capab l e o f causing the problem, and informs you of what correct ive
action you need to take.
CRU , references to optional checks are given to further narrow the fault
to one CRU .
Prob l em
No video , screen dark
No video , with raster
E l ectromagnetic f ields in the
Where the problem is isolated to more than one
CRU - - Correct ive Act ion
Power supp l y ,
printer/plotter
display unit,
-- Set brightness control c lockwis e .
I f raster appears , go to "No video
with raster . "
l ight ON power supp ly .
p l ace power supply .
test 1 6 .
trol ler Test -- Test
passes , replace CRT disp l ay unit .
test fails, perform the feature board
loading check .
" Feature Board Loading Check . "
p l ace feature board i f mal function­
ing . If not , check printer/plotter
cont ro l board wiring and CRT display
cab l ing .
not , replace p l anar board .
ter 4, "Cab l e Checks . "
CRT disp l ay
cont ro l board, cabl ing - - Perform test
1 6 .
See Section 3 . 9 , "CRT Contro l l er
Test - - Test 1 6 . "
check printer/plotter control board
wiring and CRT display cabl ing.
Chapter 4 , "Cable Checks . "
if defective .
CRT display unit .
feature
control board,
p l anar board, cabling
check + 12 V
If not ,
If OFF , re­
If ON, perform
See Sect ion 3 . 9 , "CRT Con­
1 6 . "
If test
See Section 3 . 11 . 2
Replace i f defective .
See Chap­
unit , printer/plotter
I f test
Rep lace
If test passes , replace
Fault Detection 2 - 1 3
board,
CRT
If
,
Re­
I f
fails ,
See