IBM 5150 Hardware Maintenance Manual page 69

~
Press
(Enter). This will select an all black screen and
place a signal on pins 6 and 7 of the 9 pin connector of
between 0 and 0.5 V dc. Set your meter on the 12 volt DC scale
and measure the voltage present between pins 2 and 7 and
0
pins 2 and 6.
o
1
...-----+2
3
4
5
o
WERE YOU ABLE TO READ BETWEEN 0 AND 0.5 Vdc
AT PINS 6 AND 7?
NO
Replace IBM Monochrome Display and Parallel
Printer Adapter. See Section 3,
"Removal/Replacement." ".........,
YES
400-16