AMSTRAD CPC6128 User manual

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CONTENTS
Safety Test
Keyboard Exploded View and Parts List
CPC6128 Basic Hardware Analysis
Function Diagrams
Function Diagrams
Software Errors
Diagnostic Flow Chart
Alignment Checks
CPC6128 Main PCB
CPC6128 CPU Circuit Diagram
Electrical Parts List
GT65 Exploded View and Cabinet Parts List
GT65 Circuit Diagram and Voltages
GT65 Main PCB and Alignment Instructions
GT65 Electrical Parts List
CTM644 Cabinet Drawing and Electrical Parts List
CTM644 Electrical Parts List and Alignment Instructions
CTM644 Electrical Parts List and Voltages
CTM644 Circuit Diagram
Main PCB
Interface Circuit Diagram
Disc
Control Circuit Diagram
Cassette Control Circuit Diagram
Mechanism and Mechanical Replacements
Technical Specification
Page
2
3
4
5
6
7
8,9,10,11
12,13,14,15
16,17,18
19,20
21
22
23
24
25
26
27
28
29,30
31,32
33,34
35,36
36
37
Back page
2
SAFETY TEST
All Monitors are safety tested to the following specifications.
1). Flash Test
Test
at 3kV between the live and neutral of the mains lead joined together and
and
ALL accessible metal points on the exterior of the set.
2). Insulation Resistance Test
Test
between the live and neutral of the mains lead joined together and ALL
accessible metal points on the exterior of the set to show a resistance of at
least 4Mohm.
If after servicing there is any doubt about continued electrical safety the above
tests should be carried out.
AMSTRAD CONSUMER ELECTRONICS PLC
BRENTWOOD HOUSE, 169 KINGS ROAD, BRENTWOOD, ESSEX CM14 4EF.
Telephone: Brentwood [phone]. Telex: 995417 AMSELE G.

2
1
4
KEYBOARD EXPLODED VIEW
KEYBOARD PARTS LIST
Sym Description
1 Cabinet Top Assembly
2 Frame FDD
3
Knob Volume
4 Cabinet Bottom
5 Keyboard Assembly ESU-244
6 Compact Floppy Disc Drive
EME-155
7 Volume Rotary K121 LOlOT-20KB
8 Jack RCA 3.5 HSJ1061-01-440
9UserPort Socket HXC0730-0 1-0 10
10
Jack DIN TCS4450-01-101
11 Jack DC HEC0470-01-630
12 Jack DIN TCS4460-01-1011
13 Cord DC 14550401
14 Relay G4S-1112P-1-B-19
15 Cord Connector 8W6Q004A
16 SpeakerC040K01K2451
Part No.
170855
170856
170806
170857
170858
190005
170807
170022
170023
170850
170024
170025
170822
170123
170862
170124

CPC61 28 -BASIC
HARDWARE
ANALYSIS
RED NO
LED LIGHTS >----1_--<
?
MAINS
FUSE OK
?
NO
REPLACE
MAINS FUSE
YES
{
CHECK FAULTY MONITOR
•CABLE TERMINATION
ALL OK •INTERNAL CONNECTORS
•BRIGHTNESS CONTROL
NOTHING{FAULTY ULA
Z80A
6845
CRYSTAL
RAM
FAULTY VIDEO CONNECTOR
FAULTY CABLE ASSY
FAULTY
ULA
>------< FAULTY PCB
STILL
NO
ANY
PICTURE
AT ALL
?
{
FAULTY
LED
1---- BROKEN PCB TRACK
FAULTY
CONNECTER
YES
5V NO CHECK FOR
DC PRESENT >-------l FAULTY CABLE
ON
OR PLUG ASSY
CABLE
FROM MONITO
NO
RGB
VIDEO YES
CONNECTOR >---<
INSERTED
TEST SWITCH {
ON COMPUTER
1---_ FAULTY SWITCH
KEYBOARD
UNIT
CHECK INTERNAL
CONNECTORS,
SOLDERED
JOINTS
CHECK
KEYBOARD
CONNECTOR
FAULTY AUDIO AMP OR SPEAKER
FAULTY VOLUME CONTROL
FAULTY AUDIO CONNECTOR
PLUG/SOCKET
FAULTY
AY-3-8192 SOUND IC
YES
NO
IF UNIT STILL
FAULTLY SEEK
SPECIALIST
ADVICE
NO
YES
DOES
SOUND
OPERATE
?
DO
__ I- N_
O
<ALL KEYS
OPERATE
?
NO IMPROVEMENT
SEE DISC
FLOW CHARi
CHECK KEYBOARD PCB
FOR SIGNS OF ABUSE:
-CRACKS
-LIQUID SPILLAGE
-DISTORTED MOUNTING
CHECK CONNECTOR LEAD
AND TERMINATION
REPLACE}
DISC
Full diagnostic tests on the C.P.U. can be carried out using the Amstrad RP2 Test Pack.
Please contact Amstrad PLC for information on same.
4

ICI/4
I 2
OUTPUT IQ
CONROL
FUNCTION DIAGRAMS
ICIOI
ICI06
5

CPC6128 FUNCTION DIAGRAMS
FUNCTION FOR A I1ICROCOI1PUTER AND IC's
ICI08 ICI07
IC 1/1
ADRESS
BUS
-A2
I-AI
o -Ao
-GND
8-RFSH)SYSTEI1
7-11] CONTROL
6 - RESET~to~TROL
-DUSRO CPU
- BUS
4 - WA IT CONTROL
3-BUSAK
2-lJRjSYSTEI1
I -IW CONTROL
L- ........J
ADRESS
BUS
Vo
PORTA
WRITE
CONTROL
3 -RESET
INPUTS
o
I1AI
I1A2
I1A3
Vee
---..... __ ----r-
KEYBOARD SW,
CONNCTOR NO.
234 568
10
~PD
765A
VCC
RWISEEK
lCT/DIR
FR/STP
HDl
ROY
WP/TS
FlT/TRC
PSo
PS1
WDA
USo
US1
HD
MFM
WE
VCO
RD
ROW
l..... ---.,....::.:r
WCK
RESET
R5
ViR
CS
AO
DBO
DB1
DB2
DB3
DB4
DB5
DB6
DB]
ORO
DACK
TC
lOX
INT
ClK
GND
q
5
4
7
6
3
II
12
II
DEL
!1/
II
"
ESC
Q TAB
A
APc, Z
12
LOCK
11$
If 1+
II
If
IJ
If 1/
IJ
43EWSDCX
11&
1/,;,
IJ
1/ II If
I
65R T GFBV
lie
II I
II II If
II II
1/
I
8 7 UYHJN
SPACE
KEY
1/
1/)
If
II
If
II If
11<
I
-
If;
9aILKM•
Ifi- 11=
1/ I
If
1/+
IJ;(
II?
I
>
t-IP ;.- @.
1/
II
If If
1/
II 1/ I
CLR [
ENTE
]4
ISH~~
"
CTRL
-R
f
If
'f
1/
II If
I
.-
COPE 78512
If;
II
If
II
1/
If 1/
I
t
--.
+963
ENTE
.
-R
ICI02
ANALOG
CHANNEL C
TEST I 2
Vee
ANALOG
CHANNEL B
ANALOG
CHANNAL A
Vss
lOA?
lOA.
IOAs
IOA4
IOA3
IOA2
lOA I
lOAD
6

Software Errors
If a drive fault is reported the fault may be a software problem. Before investigating the drive
please carry out the following checks to ensure it is not a software problem.
Detection and Correction of "Soft Errors"
Soft errors are usually caused by the following reasons.
1) Random external noise of several usec or less.
2) Minute off-tracking and shifting of write timing that are not detected during the write operation
which can cause the soft error during the read.
To
remedy such soft errors, take the following procedures at the controller side.
1) Repetitive reading on the track by 10 times or more until the data is restored.
2)
When the data is not restored by step 1, access the head to the adjacent track in the same
direction as move previously, and thereafter return the head to the original track.
3)
Repeat the step 1.
4) If the data is not restored by the above steps, the error cannot be remedied
Write Error
When an error is caused during the write operation, the error is usually detected during the next
rotation through the read operation called "Write check".
To correct the error, repeat the write operation again and carry out the Write check.
If the result is still incorrect even after the write operation is repeated more than 10 times, either
the disc or the drive are working incorrectly. To find out the trouble source, carry out the read
operations with another track. Should the error still be found, change the disk and repeat the above
procedures. Should error still be found, the drive should be considered defective. If the 8rror is
removed,
the original disk must be defective. Discard it.
Seek Error
1) Step motor or step motor drive circu it is defective.
2) The torque of the carriage is not correct.
Restoration procedures from the seek error.
Make the re-calibration to the track 00. Then, carry out the re-seek to the original track.
Notes:
1) Always ensure the head is clean.
2) Index/Sector Factor (Ready Defect)
As
the unit has Optional Read Output
It is normally not ready until 2 revolutions are made after the disk insertion.
7

3-A
Diagnostic
Flow Chart
This chart must be used in conjunction with
the Alignment Procedures.
This chart is for information only and
does not guarantee an exact diagnosis.
For warranty purposes any faulty drive
mechanism must be returned toAmstrad
for replacement. Service Agents should
not attempt anyrepairs on the mechanism
or to its p.e.B. P.No. 30001.
N
Motor rotation
NRead
error
N
Write error
N
Interchange-
ability error
8
Disk Drive O.K.

3-8
Motor rotation
y
FLOW CHART (cont)
N
N
N
Check wiring
Adjust to 200±1 ms
N
y
Replace motor
Replace drive
9

3-C
Read error
Test with disk
EME -CF2
y
N
N
FLOW CHART (cont)
y
Replace drive
10
Replace disk
(inspect by
drive)
Replace drive
N
N
Replace drive
N
Replace
head assembly
Replace drive
Replace
TROO sensor