Service manual

• Cassette recorder/Keyboard Block
PC1
D7
~
-\
PC5
PC4
PC3
-/
ill
Lt)
N
~
DO
Q)
u
------I
~
~
RD
c:
-
-
-
~
'" Q;
WR
.c
PA3
a.
-
.;:
)
Q)
D.
Q)
:c
CS
'"
PAO
E
-
E
~
A1
Cl
PB7
0
- .t
)
-
AO
RESET
PBO
[
l'
~
I
I
L
I
I
~
l
L
Motor
controller
~
I
I
Decoder
I
~
I
l,
I
I
I
.J"
L
-------,
WRITE
READ
I
I
I
I
SENSE
I Cassette
I
I
I
MOTOR I
______ -1
------,
9
~
o
H
)
A I
_______ J
Keyboard
Block diagram of Parts around Cassette recorder/Keyboard.
1. "LOAD" operation is
impossible.
2.
"SAVE" operation is
impossible.
3.
Motor doesn't rotate.
4.
Motor doesn't stop.
5. Key input is ineffective.
I s output signal present at pi~ of IC4?
Yes; IC5
No; IC4
Is output signal present at pin @ of IC5?
Yes; IC4
No; IC5
Is voltage at pin@ of IC2 at "Iow" level?
Yes; IC3, 01, 02
No; IC2, IC24, IC4, IC5
Is voltage at pin@of IC2 at "high" level?
Yes; IC3, 01, 02
No; IC2, IC24, IC4, IC5
Check for IC5 and IC6.
-7-
MZ-80K