f
r
r
is indicatedon the TV screen; if there is no trouble, the
cartridgesets up atest for the two keyboards.
NOTE:The Test Cartridge requires substitution
ofthe power unit during test. Use the special
500mApower unit (see Parts List) instead of the
originalpower unit.
1.Press and hold "Clear" button on Studio II console. In-
sertTester Icartridge into slot while holding "Clear" button.
NOTE: Insertcartridge into console with label
sidetoward "Clear" button. Follow label directions
concerningremoval of conductive rubber strip
coveringthe plug.
2.Release "Clear" button. Apattern similar to that of Fig.
9aappears on screen immediately, and Tester Ibegins its
scanof the system (indicated by the black streak moving
throughthe white field in the lower half of the pattern). If the
patternfails to appear or apattern other than that shown
appears,afaulty chip is indicated. Replace PC board.
Inabout 1 1 seconds,the first scan is complete. The display
shiftsto the pattern shown in Fig. 9b with awhite streak
scanningablack field. This scan takes another 11seconds. At
theend of the second scan, the system changes the pattern on
thelower half to aseries of transient vertical white lines on
blackand then aseries of black lines on white. This sequence
takesabout 2seconds. At the end of this short sequence, the
patternagain shifts- to that illustrated in Fig. 9c. This indi-
catesall memories operational. Adigit or digits appearing in
the"checkerboard" pattern in the center of the screen, as
shownin Fig. 9e, indicates chip failure in the PC board and
theboard must be replaced.
Ifthe checkerboard appears as in Fig. 9c, touch the keys
-oneat a time -of Keyboard A, and then Keyboard B. As
eachkey switch closes, the digit on screen should change to a
checkerboardsquare. (If any digit remains on screen after key
actuation,the keyboard is defective and must be replaced
(seePage 11). When all key closures are complete (indicating
CATV
CO-AX CATV
MATCHER
STUDIOII
SELECTOR
SWITCH
BOX
ANTENNA
TERMINALS
TV
RECEIVER
Figure6. Selector Switch Box Connects Between CATV Cable
Matcherand Home Receiver
ANTENNA
TERMINALS £1 nc/i
TV-« »- STUDIO II
o
-T®~L
STICKYTAPE TO
CONSOLE
Figure8. Adjust Receiver for Sharp "Freeway" Display
(d) OperableKeyboards and Electronics
mmmm^m
(e) BadKey A7 and Digital Failure
Figure7. Selector Switch Box Figure 9. Tester 1Screen Patterns