Commodore C16 User manual

SERVICE MANUAL
MODEL C16 COMPUTER
OCT. 1984 PN -314001 -03
Commodore Business Machines, Inc.
1200 Wilson Drive, West Chester, Pennsylvania 19380 U.S.A.
Commodore makes no expressed or implied war
ranties with regard to the information contained
herein. The information is made available solely on
an as is basis, and the entire risk as to quality and
accuracy is with the user. Commodore shall not be
liable for any consequential or incidental damages
in connection with the use of the information con
tained herein. The listing of any available replace
ment part herein does not constitute in any case
a recommendation, warranty or guaranty as to
quality or suitability of such replacement part.
Reproduction or use without expressed permission,
of editorial or pictorial content, in any matter is
prohibited.
This manual contains copyrighted and proprietary information. No part
of this publication may be reproduced, stored in a retrieval system, or
transmitted in any form or by any means, electronic, mechanical,
photocopying, recording or otherwise, without the prior written permis
sion of Commodore Electronics Limited.
Copyright © 1984 by Commodore Electronics Limited.
All rights reserved.

CONTENTS
Title Page
SPECIFICATIONS 1
PRODUCT PARTS LIST 3
CASEWORK IDENTIFICATION 3
PCB LAYOUT 4
PCB PARTS LIST 5
PCB SCHEMATIC DIAGRAMS 7
KEYBOARD MATRIX 8
I.C. PINOUTS FOR MOS DESIGN 9
RF MODULATOR LAYOUT 10
RF MODULATOR SCHEMATIC 10
iii/iv

C16 PRODUCT SPECIFICATION
MEMORY
16K RAM Standard
ROM
32K ROM Standard (includes operating system and BASIC interpreter).
MICROPROCESSOR
7501/8501 Microprocessor with a two speed clock (.89 or 1.76 MHz).
DISPLAY
40 Columns x 25 lines of text.
COLORS
121 Colors (15 colors; 8 luminance levels and Black).
CHARACTERS
Upper & lower case letters, numerals and symbols. Reverse and flashing characters. All PET graphic
characters.
DISPLAY MODES
Text characters. High resolution graphics. Split screen text/high resolution graphics. MultiColor graphics.
Split screen/multi-color graphics.
RESOLUTION
320 x 200 Pixels
SOUND
2 Tone generators or 1 Tone and 1 noise generator.
VOLUME
8 Volume levels
KEYBOARD
Full size/full stroke C64 style design.
KEYS
66 Keys total. 4 Cursor control keys. 4 Function keys (up to 8 user defined/programmable functions
possible). Color control keys. HELP key. Upper and lower case character set.
INPUTS/OUTPUTS
Serial port. ROM cartridge and parallel disk drive port. 2 Joystick ports. C1531 Cassette drive inter
face port. RF Output — channel 3 or 4. Video output — composite/chrominance/luminance, audio
input/output. Power supply input.

FEATURES
Built-in BASIC 3.5 — over 100 commands, statements and functions. Built-in Machine Language
Monitor — over 12 commands. Built-in graphics and sound commands. Screen window capability.
Extended screen editor.
PERIPHERALS
C1541 Disk drive, C1551 Fast Disk Drive, C1 531 Datasette, MPS 802 Dot matrix printer, MPS 803
Dot matrix printer, DPS 1101 Daisy wheel printer, C1520 Plotter/Printer, C1802/1803 Color monitor,
C1702 Color monitor.

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TOP CASE ASSY
PARTS LIST
C-16
Top Case
Keyboard, 66 Key
LED Plate
Nameplate
Lamp Holder Set
LED Assembly
C
C
C
C
C
C
251813-01
251798-01
326160-02
251794-01
903820-03
1001039-01
BOTTOM CASE ASSY
Bottom Case
Foot, Self-Adhesive
PCB Shield Plate, top
PCB Shield Plate, bottom
PCB Insulation Sheet
C
C
C
C
C
251790-01
950157-04
251795-01
251796-01
251797-01
ACCESSORIES
Users Manual
Power Supply
RF Cable
Switch Box
C 251799-01
C 251539
C 326189-02
C 904778-01
Indicates Commodore Stock Part

SOLDER
BEND
L -
BOTTOM
VIEW
DETAIL
E
O<
251081-01
SHOWN
1
1
1
251081-03
SHOWN
DETAIL
A
SEE
DETAIL
E
FOR
-01
TO-03
\
R2|
~\+
CI7
1
1
14
Is
C[
Ftlt
Fl
11
R20
/~\+
Uli
UI2
*Jc«3
ipnr TO
II
*•
1
■
UIO
CD l
u
TSQ5
C2fi
■
FBI
4
j1
►
UM
1
1
IS
US
«i
WP3
UT
18
US
i
18
U8
X.
Ml
v
ASSY
NO
250^43
PCB
NO
251789-0
|
REVA
QZI^o
COMMODORE
16©
1984^
20
UI3
SEE
DETAIL
A
C-16PCB
Assembly

PARTS LIST - C-16 PCB ASSEMBLY #250443-01
PLEASE NOTE: Commodore part numbers are provided for reference only and do not indicate the
availability of parts from Commodore. Industry standard parts (Resistors, Capacitors,
Connectors) should be secured locally. Approved cross-reference for TTL chips,
Transistors, etc., will be available in manual form through the Service Department
in November of 1984. Unique or non-standard parts will be stocked by Commodore
and are indicated on the parts list by a "C".
INTEGRATED CIRCUITS
U1
U2
U3
U4
U5,U6
U7,U8
U9
U10
U11
U12
U13
U14
U15
U16
IC 7360 VSLI, '
Sub: IC8360
fext Display (TED)
C 251535-01
C 251535-02
IC 7501 Custom Microprocessor
IC 23128 ROM
IC 23128 ROM
Sub: IC23128
IC D-RAM 16 x
IC 74LS257
IC 7406
IC 555
IC 74LS125
IC 74LS02
C 251536-01
TED Basic
C 318006-01
TED Kernal
C 318005-05
C 318005-04
4 251538-02
901521-57
901522-06
901523-01
901521-20
901521-21
IC 6529B Single Port Interface
IC 74LS139
IC 74LS175
<J ZblO4U-U3
901521-18
^y^y 1 ^J mm 1 1 ^J
901521-34
IC 7700-010 PLA C 251641 -02
TRANSISTORS
Q1
Q2
Q3
Q5
niAncc
LJIULJCO
D1-D10
D11
D12
2SC 1815
2SC 1815
2SC 1815
2SD 880
902693-01
902694-01
IN914B FORMING 251819-16
Sub:
15953(3) FORMING 251819-07
IN4001
900750-01
ZENER RD 6.8EB 900927-01
Sub: ZENER IN754A 900927-02
RESISTORS - All values
R1
R2
are in ohms-1/4 W
5%, Carbon Comp - Forming
Typ, unless noted otherwise.
10K
4.7K
R3
R4
470K
220K
RESISTORS (Continued)
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
RESISTOR
RP1
RP2
RP3
RP4
RP5
18K
1.5K
470K
1K
12K
Wound 20K
5W,10%
10K
3.3K
470K
470K
R20
R21
R23
R24
R25
R26
R27
R28
R29
R102
47K
100K
10K
1K
100K
240K
240K
1K
100K
330K
PACK
1K 6 PIN 0.19W 2% 902441 -22
3.3K 6 PIN 0.19W 2% 902441-29
68K 8 PIN 326149-06
68K 8 PIN 326149-06
3.3K6 PIN 0.19W2% 902441-29
CAPACITORS
C1
C2
C3
C4
C5
C6
C7
C8
C10
C11
C12
C13
C14
C15
C16
C17
C18
C19
C20
C21
C22
Elect VF 25V 900100-32
Elect 47 /*F 25V 900100-33
Elect 10/tF25V 900100-01
Elect 10/tF25V 900100-01
Ceramic 0.1 /*F 25V 251075-06
Ceramic 0.1 /if 25V 251075-06
Cermaic 0.22 ftF 25V 251075-07
Ceramic 0.22 nF 25V 251075-07
Ceramic 0.1 »F 25V 251075-06
Ceramic 0.1 /d= 25V 251075-06
Ceramic 22 pF 50V 251070-14
Ceramic 220 pF 50V 251071-26
Ceramic 150 pF 50V 251071-24
Ceramic 0.01 pF 25V 251075-01
Elect 10 ^F 25V 900100-01
Elect 1 pF 16V 900100-16
Elect 10/iF25V 900100-01
Elect 10/iF25V 900100-01
Ceramic 0.01 /*F 25V 251075-01
Ceramic 0.1 /tF 25V 251075-06
Ceramic 0.1 /tF 25V 251075-06
C — Commodore Stock Item

PART LIST - C16 PCB ASSEMBLY #250443-01 (Continued)
CAPACITORS (Continued)
C23
C24
C25
C26
C28
C30
C31
C32
C33
C34
C200
CT1
Ceramic 470 pF 50V 251071-30
Ceramic 470 pF 50V 251071-30
Ceramic 470 pF 50V 250171-30
Ceramic 0.1 pF 25V 251075-06
Ceramic 0.1 pF 25V 251075-06
Ceramic 0.1 ^F 25V 251075-06
Elect 10 jiF 25V 900100-01
Ceramic 0.1 /iF 25V 251075-06
Ceramic 0.1 /iF 25V 251075-06
Ceramic 0.1 /iF 25V 251075-06
Ceramic .22 pF 25V 251075-07
Capacitor, Trimmer 251029-02
MISCELLANEOUS
Y1
L1
L3
SW1
SW2
VR1
F1
F1
Crystal 14.31818 MHZ -
CL - 32 pF 251081-03
Sub:
Crystal 14.31818 MHZ 251081-01
Coil Inductor 1.2 uH 325570-01
Line Filter 251701-01
Switch, Rocker (PC Mount)
C 251587-01
Switch, Push Button C 251260-01
Voltage Regulator 7805 901527-02
Fuse, Normal BLOW 250V 1.5A
903556-18
Fuse, Clip 906102-01
MISCELLANEOUS (Continued)
M1
FB1-5,
FB12-19
FB22,
FB24-35
FB37-56,
FB58
EM 1-5
Cartridge Guide C 310171-01
Connector Panel 251791-01
RF Modulator C 251844-01
Ferrite Bead 325563-01
EMI Filter 251842-01
CONNECTORS
CN1
CN2
CN3
CN4
CN5
CN6
CN7
CN8
CN9
Connector, 50 PIN Female Edge,
Expan. Gold Plated 251630-02
Header Pin, 20 PIN, Keyboard
903364-01
Connector, 7 PIN MINI DIN,
Cassette C 251616-01
Connector, 8 PIN MINI DIN,
Joy 0 Joy 1 C 251259-01
Connector, 8 PIN MINI DIN,
Joy 0 Joy 1 C 251259-01
Connector, 8 PIN DIN,
Audio/Video C 325573-01
Connector, 6 PIN DIN,
Serial Bus C 903361-01
Connector Jack, DC Power,
Power C 251263-01
Header Assembly, 3 PIN, LED
903332-03
C — Commodore Stock Item

PIN
ASSIGNMENT
PIN
ASSIGNMENT
PIN
CONFIGURATION
A2-
A1-
A0-
VDD-
CSO-
CS1-
R/W-
IRQ-
MUX-
RAS-
CAS-
<t><D -
COLOR-
CLK IN-
K0-
K1-
K2-
K3-
K4-
K5-
K6-
K7-
SYNC-
VSS-
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
48
47
46
45
44
43
42
41
40
39
7360 f$
36
35
34
33
32
31
30
29
28
27
26
25
-A3
-A4
-A5
-A6
-A7
-A8
-A9
-A10
-A11
-A12
-A13
-A14
-A15
-AEC
-BA
-SND
-D7
-D6
-D5
-D4
-D3
-D2
-D1
-DO
U1-251535-01
VLSI, TEXT DISPLAY
(TED)
RDY-
IRQ-
AEC-
VCC-
AO-
A1-
A2-
A3-
A4-
A5-
A6-
A7-
A8-
A9-
A10-
A11
A12
A13-
GND-
1
2
3
4
5
6
7
8
9
]° 7501
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
-RES
-R/W
-DO
-D1
-D2
-D3
-D4
-D5
-D6
-D7
-PO
-P1
-P2
-P3
-P4
-P5
-P6
-GATE
-A15
-A14
U2-251536-01
CUSTOM MICROPROCESSOR
PIN
ASSIGNMENT
ENABLE-
DO-
D1-
WE-
RAS-
A6-
A5-
A4-
VDD-
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
U5-U6 16X4 D-RAM
NC-
A12-
A7-
A6-
A5-
A4-
A3-
A2-
A1-
AO-
D1-
D2-
D3-
GND-
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
23128 22
21
20
19
18
17
16
15
-vcc
-cs3
-A13
-A8
-A9
-AJ.1
-CS,
-A10
-CS2
-D8
-D7
-D6
-D5
D4
U3-318006-01
ROM TED - BASIC
PIN
CONFIGURATION
NC-
A12-
A7-
A6-
A5-
A4-
A3-
A2-
A1-
AO-
D1-
D2-
D3-
GND-
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
23128 22
21
20
19
18
17
16
15
-VCC
-cs3
-A13
-A8
-A9
-A11
-CS,
-A10
-CS2
-D8
-D7
-D6
-D5
-D4
U4-318005-04
ROM TED - KERNAL
PART NO.
251538-02
-02
-02
-02
SUGGESTED
SOURCE
OF SUPPLY
TEXAS INSTRUMENT
FUJITSU
MITSUBISHI
HITACHI
VENDOR
PART NO.
TMS4416-15
MB81416-15
M5M4416P-15
HM48416AP-15
ACCESS TIME
FROM RAS
TRAC (ns)
150
150
150
150
RANDOM READ/
WRITE CYCLE
TIME TRACT (ns)
260
260
260
260

Color
<O
C-16
Schematic
#251788
(1
of
3)

(13)
T
(15) (14
CLEAR
HOME
(
9
INST
DEL
RETURN
CTRL
RUN
STOP
SHIFT
N
SPACE
B
H
U
M
.K
ESC
f1
f2
J3
C16
KEYBOARD MATRIX
.6
H
-i)
HELP
SHIFT LOCK
SW

O/f
LED
COA/A/£Cro/f
-Aft
0
00000
2
\
a
l§
15
C-16
Schematic
#251788
(2
of
3)

PIN
CONFIGURATION
cs
L
L
H
R/W
L
H
X
DO-D7
DATA BUS
TO PORT
PORT TO
DATA BUS
ISOLATION
L = LOW LEVEL
H = HIGH LEVEL
X = IRREVELANT
R/W-
P0-
P1-
P2-
P3-
P4-
P5-
P6-
P7-
VSS-
1
2
3
4
5
6
7
8
9
10
20
19
18
17
6529 16
15
14
13
12
11
-VDD
-CS
-DB0
-DB1
-DB2
-DB3
-DB4
-DB5
-DB6
-DB7
U13-251640-03
SINGLE-PORT INTERFACE
MOS
6529B
3 MHZ
PIN
CONFIGURATION
FE-
17-
16-
15-
14-
13-
12-
11-
10-
F7-
F6-
F5-
F4-
GND-
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
-vcc
-18
-19
-110
-111
-112
-113
-114
-M_5
-CE
-F0
-F1
-F2
-F3
U16-251641-02
PLA

1.
ALL
RESISTANCE
VALUES
IN
OHMS,
1/4W
±5%.
NOTES:
UNLESS
OTHERWISE
SPECIFIED
-
C-16
Schematic
#251788
(3
of
3)

COLOR IN O
LUM /N
ta o
AUD/O /N O
O COLOR. OUT
OUT
COMPONENT PARTS VALUE: R = Q, C
Q3, Q4: 2SC460 OR EQUIVALENT.
Q1, Q2: 2SC1684 OR EQUIVALENT.
D3, D4: 1SS198 OR EQUIVALENT.
D2 : 1SS110 OR EQUIVALENT.
D1 : 1SS119 OR EQUIVALENT.
F, L = H
RCA. PHONO JAC
TOP VIEW
NO.
1
2
3
4
5
6
7
8
9
10
TERMINALS
N.C.
AUDIO SIG. INPUT
+ B ( + 5V)
SYNC + LUM. SIG. INPUT
COLOR SIG. INPUT
COLOR SIG. OUTPUT
COMPO. SIG. OUTPUT
SYNC + LUM. SIG. OUTPUT
RF OUTPUT
CHANNEL SELECT SW.
REAR VIEW
RF Modulator Layout and Schematic #251844
10

i
i
Issue 7, 1984 :
Model: C16, PLUS
LINE DEFINITIONS
AO to A15
AEC
ATN
BA
BRESET
Cl HIGH, Cl LOW
C2 HIGH, C2 LOW
CAS
CLK IN
COLOR
COMP
CE
CS
CSO
CS1
CST MTR
CST RD
CST SENSE
CST WRT
CTS
DBO to DB7
DCD
DRAM
DRAM ADD
DSR
DTR
EXT AUDIO
GATE IN
IRQ
KO to K7
KERN
LUM
MUX
PO to P7
RAS
RESET
RxC
RxD
R/W
RTS
SND
TED
TxD
?0
/2
computer 4 m ^. conrinnociope
^ TECHTOWCS
© 1980 COMMODORE BUSINESS MACHINES INC.
Address Bit 0 to 15
Address Enable Control
Attention
Bus Available
Buffered System Reset
External Cartridge Chip Select
11
Dynamic RAM Column Address Strobe
Master Clock (Single Phase, 14.31818 MHz)
Chroma Output
Composite Chroma and Luma
Chip Enable
Chip Select
Low ROM Chip Select
High ROM Chip Select
Cassette Motor Control
Cassette Read
Cassette Sensor
Cassette Write
Clear To Send
Data Bit 0 to 7
Data Carrier Detect
Dynamic RAM
Dynamic RAM Address
Data Set Ready
Data Terminal Ready
External Audio Input
R/W GATE
Interupt Request
Keyboard Latch 0 to 7
Kernal ROM Control Line
Composite Sync and Luminence
Address Multiplex Control
Port Bit 0 to 7
Dynamic RAM Row Address Strobe
System Reset
Receive Clock
Receive Data
Read/Write Line
Request To Send
Sound Line
Text Display
Transmit Data
System Clock (Varies between 1 and 2 MHz)
Artificialf 2, Address Valid Rising Edgef
Data Valid Falling Edge

Issue 5, 1984 : Computer 2
Model: C16
W A
TECHTOPICS
© 1960 COMMODORE BUSINESS MACHINES INC.
Troubleshooting Aides
NOTE: Visual inspection is critical in this unit!
The upright position of many of the components used on the
board can create problems. It is possible for them to be
shorted to the shield or to each other. Make sure they are
evenly spaced and do not contact the shield.
1) NO VIDEO - Absolutely no video on screen
A) Check for 5 volts
i
B)
C)
D)
O.K.
Check
O.K.
Check
for
for
If
osc
If
LUM
the modulator
and at
O.K.
Check
O.K.
Check
Signal
AEC
AEC
CAS
CS1
CS1
CSO
CSO
pin 1
for
for
I
If
not:
1)
2)
3)
4)
5)
6)
Check
Check
( 5 V.
Check
Check
Check
+ 9 V.
Check
fuse
for twisted or
bent
short to ground )
LI
5 V. regulator
if top shield
(Blown fuse)
if top shield
caps
shorts to
is
shorting 5 V. to ground
illation at pin 14 of Ul
not:
1)
2)
signal
, at
Check
pin 14
Check
for good connection
of Ul
for good connection
Rl thru R7~
at pin
pin 8 of
of CN6
not:
reset
control
.C.
Ul
U2
Ul
Ul
U14
Ul
U14
Pin
35
4
11
6
15
5
1
1)
2)
3)
Check
23 of Ulf at
the modulator,
for LUM signal
to ground
Check
Check
signals:
pin 4
at
at
of
at EM3
shorted
for open traces
modulator
Signal I
R/W
0
MUX
IRQ
RDY
BA
RAS
.C.
Ul
Ul
Ul
Ul
U2
Ul
Ul
Pin
7
12
9
8
2
34
10

C16 Troubleshooting Page 2
2) BAD VIDEO - Scrolling lines on screen - Random
blocks on screen - Blurred display
A) Check Ul for proper operation
O.K. If not: 1) Check socket for good solder
* 2) Check for bad Ul
B) Check U2 for proper operation
O.K. If not: 1) Check socket
♦ 2) Check for bad U2
C) Check RAM data lines for correct amplitude
O.K. If not: 1) Check for hot surface of RAM
i 2) Jump out RAM to verify
D) Check multiplexers U7, U8 - signals at RP3
and RP4 should be similar in frequency and
amplitude
O.K. If not: 1) Suspect U7 or U8
E) Check ROM for chip select signal at pin 22 of
U3 and U4
O.K. If not: 1) Check for signal generation
+ at U14
F) Check that all ROM addresses are present and
correct amplitude
O.K. If not: 1) Trace problem address A0-A15
G) Check U16f U3, U4 by replacement with known
good
3) NO POWER
A) Verify voltage +5 and +9 volts
1) Check for shorts to ground
2) Check switch
3) Check power supply
4) BAD BASIC - Random characters on screen - Random
colors - Power-up message is missing
A) Check Basic ROM U3
B) Check A thru G above (Bad Video)

C16 Troubleshooting Page 3
5) NO COLOR or BAD COLOR
A) Check Ul pin 14 for 14.31818 MHz with
frequency counter
O.K. If not: 1) Check solder joints of CT1
and adjust for correct frequency
+ 2) Check crystal, Ql and Q2
3) Check clock circuit for
opens or shorts
B) Check Ul pin 13 for Color Out signal.
O.K. If not: 1) Swap Ul w/known good
C) Check modulator Ml pin 5 for Color In signal
and pin 6 for Color Out signal
O.K. If not: 1) Check Ml operation
D) Check EM4 and CN6 pin 6 to see if color signal
is present.
1) Check for shorts
6) NO SOUND or BAD SOUND
A) Check Ul pin 33 for SND signal
O.K. If not: 1) Check socket for. open circuit
4 2) Swap Ul w/known good
B) Check audio circuit for short to ground or loss of
signal.
O.K. If not: 1) Check Q3 - Be sure emitter and base
i are not shorted to 5 V.
C) Check modulator Ml pin 2 for SND signal
1) Adjust I.F. can (top right of
modulator) for clean, loud volume
2) Ml pin 2 to ground should read
approximately 480 ohms
3) Check Ml for component failure
7) SERIAL FAILURES
A) Check FB14-19 for shorts to shield or each other
(has caused serial port problems)
B) Check FB1-5 for shorts to shield or each other
C) Check U9, U2 and CN7