Radio Shack TRS-80 26-3650 - Page 34

CONTENTS
I. POCKET
COMPUTER
(26-3650)
&
MEMORY
MODULE
(26-3653)
1.
SPECIFICATIONS
-,
2.
BLOCK DIAGRAM
3
3. CPU (Central Processing
Unit)
3—1
Features
4
3-2
CPU Block Diagram
4
3—3
CPU Signal Descriptions
5
4. RAM
(Random Access Memory)
5. SERVICING
5—1
Disassembly
7
5—2
Troubleshooting
3
A Display
g
B Key
Entry
g
C RAMI
g
D RAM2
9
E
Discrimination
Between
CPU and
RAMI
10
5—3
Test
Program
11
6. PROGRAM COMMAND
LIST
13
7. ERROR
MESSAGE
LIST
15
II. CASSETTE
INTERFACE
(26-3651)
1.
SPECIFICATIONS
16
2. BLOCK
DIAGRAM
16
3. LSI
(HD431
10)
17
4.
CIRCUMFERENCE CIRCUITS
4—1
Clock Pulse
Generator
18
4-2
Remote Control Circuit
18
4—3
Shaping
Circuit and
Filter
18
5.
SERVICING
5—1
Disassembly
20
5—2
Troubleshooting
21
III. CIRCUIT DIAGRAM
1.
26-3650
22
2.
26-3651
23
IV.
PRINTED CIRCUIT BOARD
1.
26-3650
24
2.
26-3651
24
3.
26-3653 25
VI.
PARTS
LIST
1.
26-3650
26
2.
26-3651
29