Sam 3 Raster Problem Isola Tion - Control Data Corporation CDC CC63X Hardware Maintenance Manual

SAM 3-1
SAM 3 RASTER 'PROBLEM ISOLATION
Preprequisite: To use this SAM you must be able to:
A. LOCATE the following components
• crt/yoke
• ,crt socket
• anode lead
• yoke inline connector
• monitor board and plug from control assembly
• BRIGHTNESS/CONTRAST control assembly
• J3 on power 'supply board
• J5 on main logic board
r
• monitor box shield assembly \" "
• G2 pot on monitor board (remove access lid, procedure 3)
Assumptions: No raster observed after turning G2 pot and
BRIGHTNESS control fully clockwise. (G2 must be readjusted per
procedure 16 at completion of testing.) Remove option boards
installed in I/F 1 through I/F 3. If raster can be obtained
after I/F 1 through I/F 3 boards are removed, reinstall one at a
time to determine which'onecausesthe problem. All four power
supply LED's are lit. If no 24 V LED go to step 001 of this SAM,
if no +5, +12 or -12 V
LED,~s
lit go to SAM 2, step 003.
6A-6
NOTE
The corrective actions in this SAM
assume that cables are good. Before
replacing an item; check all
associated cables for damage or
shorts. Before starting this SAM,
verify the 'following connections are
properly seated: (check only after
terminal has been disconnected from
the outlet for 60 seconds).
• anode lead from crt to monitor
board
• yoke inline connector
• socket at end of crt
• monitor cable from BRIGHTNESS/
CONTRAST control to monitor board
connector
• DC power cable from J3 power
supply board to P5 main logic
board
• jumper for alpha/graphics is
installed correctly on main logic
board
62940034 D