IBM 5150 Hardware Maintenance Manual page 70

~
Press (Enter) and wait for two beeps.
The signal on pin 8 (horizontal sync) shO"~,lld be between
0.4 and 1.1 Vdc, and on pin 9 should be between 3.0 and
4.2 V dc. Refer to the diagram below. Set your meter on
the 12 volt DC scale and measure the voltage present at
pin 8 and pin 9.
0
•
1
2
3
4
5
0
WERE YOU ABLE TO READ BETWEEN 0.4 AND
1.1
Vdc
ON PIN 8 AND BETWEEN 3.0 AND 4.2 Vdc ON PIN 9?
NO
Replace IBM Monochrome Display and Parallel
Printer Adapter. See Section 3,
"Removal/Replacement. "
YES
400-17