Table of Contents
Advertisement
6)
Composite Video Signal Adjustment
(PAL
Version
Only)
A.
Horizontal Sync Pulse Width
ad jus tment
Connection: connect oscilloscope
to
JK5 (Composite
VIDEO
OUT)
Procedure:
adjust VR2
to
get
4.7 psec, sync pulse
width.
64
jjSte
UT
\s
B.
Burst Start Position adjustment
Connection: connect oscilloscope
to
JK5
(Composite VIDEO
OUT).
Procedure:
1.
Turn VR101
to
fully
counterclockwise.
2.
Turn VR101 clock-
wise
to
obtain
5.6usec. burst
start position.
3.
If
the
start
position
does not
become 5.6usec,
adjust
it
for
maximum.
4.
Check
to see the
burst appears every
1H
(64usec.)
M
64
p
Sec
u^
\tf
\i
BunT
Signal
C.
Composite Video Output Level
adjustment
Connection: connect Oscilloscope
to
JK5 (Composite
VIDEO
OUT)
terminated
by
7
5
ohms
Procedure:
adjust
VR1
to
get
output level of
l.OVp
-P.
6.3
Keyboard Problems
No Keyboard Entry /Wrong Character
•
Check Flex Cable and CN2
•
Check pin
23 (CS2*) of IC5
•
Check D8
-
Dll, C18,
19,
22,
23
and
IC14
6.4 Processing Problem
•
Check OSC Circuit
(
•
Check TP2 and TP3
(
(Waveform
7)
•
Check TP4
and TP5
(
(Waveforms
8
and
9)
11
of IC6 (WEO*, WE
•
Check Address decod
•
Check SO
-
S2
•
Check pin
40 of IC5
18
of IC5 (VSYNC*)
of IC5 (IRQ*)
•
Check
pin 40 of
IC1
of
IC1 (NMI*) and
p
(FIRQ*)
-
these pin
High
6.5
Cassette Problems
IC6)
ECLK
and QCLK)
RAS*, CAS*)
and pins
10
and
1*)
e
circuit
(IC9)
(HSYNC*), pin
and pins
37,
38
(HALT*), pin
2
in 4
of ICI
s
are normally
1)
Motor Control Problem
•
Run
the
following program
and
check
pin
39 of IC4
(Waveform
14)
•
Check pin
9
of IC8 (SALT)
10
POKE 65313,60
20
GOSUB
100
30
POKE 65313,52
40 GOSUB 100
50
GOTO
10
100
FOR
A=l
TO
10:
NEXT A
110
RETURN
2)
Write Problem
•
Run
the
following Program
and
Check
pin
17
of 1C7 and
Pin
1
of IC7.
(Waveform
13)
10
SOUND 200,255
20 GOTO
10
3)
Read Problem
•
Connect
pin
4
and pin
5
of JK4
•
Run
the
above
program
and check pin
11
of IC8
•
Check
pin
7
of IC8
«
Check
R14,
C25
-56-
Advertisement
Chapters
Table of Contents
