AMSTRAD CPC6128 User manual

M
CPC6128
MICROCOMPUTER
CTM644
COLOUR MONITOR
GT65 GREEN MONITOR
SERVICE MANUAL
PRICE: £8.00

CONTENTS Page
Safety Test 2
Keyboard Exploded View and Parts List 3
CPC61 28 Basic Hardware Analysis 4
Function Diagrams 5
Function Diagrams 6
Software Errors 7
Diagnostic Flow Chart 8,9,10,11
Alignment Checks 12,1 3,1 4,1
5
CPC6128 Main PCB 16,17,18
CPC61 28 CPU Circuit Diagram 19,20
Electrical Parts List 21
GT65 Exploded View and Cabinet Parts List 22
GT65 Circuit Diagram and Voltages 23
GT65 Main PCB and Alignment Instructions 24
GT65 Electrical Parts List 25
CTM644 Cabinet Drawing and Electrical Parts List 26
CTM644 Electrical Parts List and Alignment Instructions 27
CTM644 Electrical Parts List and Voltages 28
CTM644 Circuit Diagram 29,30
Main PCB 31,32
Interface Circuit Diagram 33,34
Disc Control Circuit Diagram 35,36
Cassette Control Circuit Diagram 36
Mechanism and Mechanical Replacements 37
Technical Specification Back page
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 aresistance 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.

KEYBOARD EXPLODED VIEW
KEYBOARD PARTS LIST
Sym Description Part No.
1Cabinet Top Assembly 170855
2Frame FDD 170856
3Knob Volume 170806
4Cabinet Bottom 170857
5Keyboard Assembly ESU-244 170858
6Compact Floppy Disc Drive
EME-155 190005
7Volume Rotary K1 21 L0Z0T-20KB 170807
8Jack RCA 3.5 HSJ 1061 -01 -440 170022
9User Port Socket HXC0730-01 -01 170023
10 Jack DIN TCS4450-01-101 170850
11 Jack DC HEC0470-01-630 170024
12 Jack DIN TCS4460-01-1011 170025
13 Cord DC 14550401 170822
14 RelayG4S-1112P-1-B-19 170123
15 Cord Connector 8W6Q004A 170862
16 Speaker C040K01 K2451 170124

/connect to
(240v ac mains CPC6128 —BASIC
HARDWARE ANALYSIS
CHECK KEYBOARD PCB
FOR SIGNS OF ABUSE:
-CRACKS
-LIQUID SPILLAGE
-DISTORTED MOUNTING
CHECK CONNECTOR LEAD
AND TERMINATION
IF UNIT STILL
FAULTLY SEEK
SPECIALIST
ADVICE
FAULTY AUDIO AMP OR SPEAKER
FAULTY VOLUME CONTROL
FAULTY AUDIO CONNECTOR
PLUG/SOCKET
FAULTY AY- 3- 8192 SOUND IC
FAULTY VIDEO CONNECTOR
FAULTY CABLE ASSY
FAULTY ULA
FAULTY PCB
CHECK FAULTY MONITOR
#CABLE TERMINATION
#INTERNAL CONNECTORS
#BRIGHTNESS CONTROL
FAULTY ULA
Z80A
6845
CRYSTAL
RAM
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.

FUNCTION DIAGRAMS
ICII4 VCC SQ SD ID 70 60 SD SD 50
mmm m pfi p?i un mmENABLE
ENAB
QES\Tf0E
&,OF
=C
tal 13 2>| \D
o°fa| ,0£
J
§0f
o"ca
Tjrmmmmmijwmw
OUTPUT IB ID 2D 20 30 3D 4D 40 GND
C0NR0L
ICIIS Vcc 2G IYI 2A4 IY2 2A3 IY3 2A2 IY4 2AI
wLlLlLlLlLllLllllJLllL£j
IQIAI 2Y4 IA2 2Y3 IA3 2Y2 IA4 2YI GND
ICI04.I05 STROBE ADATA INPUT'S OUTPUT
ICI09.II3 VCC 2G SELECT ^" 'lT"lf ^J-3
V
^2C3 2C2 2CI 2C0 21
^
A
Hi hi lu mHi ill LiJ m
STROBE B''OUTPUT
IG SELECT DATA INPUTS IY GND
VCC 4B 4A 4Y 3B 3A3Y
m m f«i mmm m
uill ill Hi mHi LzJ
IA IB IY 2A 2B 2Y GND
ICIOI INPUTS
VCC ABcD' Isz_
mus] m m mmmrti
j
ABCD
BCD-TO-DECIMAL
I23 4 5 5 7 8_1
X
I4J L4J 3j I4J L^J 1_|J L^J l«j
OUTPUTS GND
ICII2 Vcc 4B 4A 4Y 3B 3A 3Y
[mi mi/Fi [77i poi ri m
111 111 LU 111 111 LiJ IU
IA IB IY 2A 2B 2Y GND
ICI06 VCC 30 8D ID 10 60 6D SD 50 CLOCK
[^[7jn[7F|[77l|76l[75l [771 [7J1[7J1 1771
11 lil 11 LI ill LI LI II lAj n
LEAR IQ ID 2D 20 JO 3D 4D 40 GND
VCC 6A 6Y 5A 5Y 4A 4Y
4Ui3Uig_fiTlJioU9lJ8l
iinin3n4j-i5nif
TiiliJlkliJlkJIillzf
1A 1Y „2A 2Y 3A 3Y GND

FUNCTION FOR AMICROCOMPUTER AND IC'S
CPC6128 FUNCTION DIAGRAMS
Vss E
RES H
LPSTE E
MAC E
MAI E
MA2 E
MA3 E
MA4 K
MAS E
MA 6I
MA7 E
MAS 1
MAI E
MAIL E
MA II E
MA 12 EI
MA 13 Ez
DISPTMG l»
CUDISP EI
Vcc ]20
VSYNC
ADRESS
BUS
I/O
PORTB
w\~Aio
H-X!
ZZH?
M~Ae
1-/15
EH<
IHi
E'Al
M~Ao.
^~GND
M~RFSH ]SYSTEM
^mJCONTROL
M^REsTt^-cpu
_j ncoci CONTROL
x\~nusRa-~i—cpu
E-MTtjJ ^CONTROL
ZJi^BUSAK -
22\~WR)SYSTEM
KEYBOARD SW.
ANALOG
CHANNEL CEl
rEST 1E
Vcc
ANALOG
CHANNEL B
ANALOG
CHANNAL A
E
E
E
Vss EC
10A? E
10As E
10As E
10A4 E
10A3 E
10A2 E
lOAl EI
lOAo E
ICI02
CONNCTOR NO.
234
O
[7"
DEL
"T,
7~
7~~
CLR
7~
71
COPE
S7
P9
ESC
7~
i
®
ENTE
R
V
TAB
7"
7"
7~
T
Tl
T
TSHIF
T
T
CAPS
LOCK
7
\
7"
7
ENTE
R
V
V
SPACE
KEY
CTRL
T-0/9
RESET C
RD C
WR C
CS C
AC
DB C
DBi C
DB 2C
DB3C
DB4C
DB5C
DB6C
DB7C
DROC
DACKC
TCC
IDXC
INTC
CLKC
GNDC
i<^—
2
3
4
5
6
7
10 765A
11
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
3VCC
3RW/SEEK
3LCT/DIR
3FR/STP
JHDL
3RDY
3WP/TS
3FLT/TRc
DPS
DPS!
3WDA
DUS
3US!
•3 HD
3MFM
,3 WE
DVCO
3RD
]RDW
DWCK

Software Errors
If adrive fault is reported the fault may be asoftware problem. Before investigating the drive
please carry out the following checks to ensure it is not asoftware problem.
Detection and Correction of "Soft Errors"
Soft errors are usually caused by the following reasons.
1) Random external noise of several usee 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 error is
removed, the original disk must be defective. Discard it.
Seek Error
1) Step motor or step motor drive circuit is defective.
2) The torque of the carriage is not correct.
Restoration procedures from the seek error.
Make the re-calibration to the track OO. 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 2revolutions are made after the disk insertion.

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 to Amstrad
for replacement. Service Agents should
not attempt any repairs on the mechanism
or to its P.C.B. P.No. 30001.
3-A
Motor rotation
Read error
Write error
Interchange-
ability error
Disk Drive O.K.

3-B
FLOW CHART (cont)
Replace motor Replace drive

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

FLOW CHART (CONT)
3-D
Open
Repair
head connector
Write error
NG
Short
Replace
control PCB
OK
OK
Amplifier
system
Head system
Replace drive
Media failure
Adjust
positioning
Adjust
index timing
11

The data contained in the following 4pages is for information only. Service Agents must not carry
out any repair or adjustment to the Drive mechanism and its associated PCB 30001 during
warranty. Faulty mechanism must be returned to AMSTRAD for exchange.
Alignment Checks
Please use this this information in conjunction with the diagnostic flow chart.
Equipment required: Double Beam Scope; EME -CF2 Test Disk (please refer to disk notes for usage).
The following checks can be carried out in routine servicing. If the wave patterns do not appear this
confirms afault with the mechanism. Before attempting any replacement check these waveforms
thoroughly.
Content of adjustment and checking
1
.
Redial adjustment by use of Track 19(Fig. 1).
2. Adjustment of the index burst by use of Track 39 (Fig. 2).
3. Azimuth check by use of Track 39 (Fig. 3-4).
CE DISK
EMECF2
O
o
o
List of Test Points
Test point Name of signal
TP 1Read signal of filter outlet
TP2 Read signal of filter outlet
TP3 Signal ground
TP5 TROO sensor output
TP9 Index signal
TP 11 Signal ground
2ms 2ms
*-« 1
n0.5
ms
2F IF
BLOCK 2
ii
BLOCK 3
i1
BLOCK 49
r1
IF
fc __500us "H_h-
^s 5°°HS
-0-
200ms (TOTAL 49 BLOCKS)
INDEX INDEX
Fig .1 Waveform of T19 (Servo pattern)
12

ALIGNMENT CHECKS
500|jsec
Fig. 5-1 Index burst waveform
Amplitude
ratio (%)
uu
80
40
20 ^
10 20 30 40
Amount of Off-center (p)
Fig. 5-2 Off-centre calibration curve
(Effective width of read head is 180u)
(b)
Kb)
Inner: b/a x100%
Outer: a/b x100%
50
Fig. 5-3 Azimuth burst
-48'
-72' +48'
-"B-B- +72' fl-
&
Fig. 5-4 shows azimuth burst in the cases of azimuth -12', 0' and +12.
f3

ALIGNMENT CHECKS (cont)
MEDIA 300fjs
500us
2F (125kHz
INDEX
Difference between Track 00 and 39
is within 18us (2')
Fig. 2Waveform of T39 (Index pattern -Radial alignment)
.8ms
-500|js
INDEX I.B
0.6 ms
0.1ms
100%
2F(l25kH2
12 34
Fig. 3Waveform of T39 (Azimuth, alignment)
+72'-48' +48'-72'
LJL BLOCK 1BLOCK 2BLOCK 3 JLBLOCK 47
i
Index Aximuth burst
burst 47 pair servo-patters for posi*ioning use
Fig. 4Waveform of T39
14

ALIGNMENT CHECKS (cont)
1) Check Positioning
1) Load CE Disk.
2) Set up track OO, Motor off.
3) Scope to TP5.
4) Adjust OO Sensor (8 on Fig. 6) so that scope shows correct difference as Fig. 2.
2) Adjustment of Index Timing
1) Load the CE Disk (refer to disk info)
2) Step the disk to the track 39.
3) Synchronise the oscilloscope by TP9 (INDEX). Set the time base to 0.1 msec/DIV.
4) Connect the probe to TP1.
Connect the ground probe to TP3 and TP1 1(ground) of PCB.
Set the input to AC and set the vertical axis to 20mV/DIV.
5) Measure timing between sweep start and an initial data pulse. It should be 500 usee ±500 usee.
When the timing is not within this range, proceed with the following adjustment. (Refer to Fig. 5-1 ).
6) Loosen the two screws fixed LED printed board. Adjust the position of LED printed board so that the
timing is 500 usee +100 usee.
7) Re-check the timing.
8) Seek to the track 00 and make sure that the timing is within 500 usee +200 usee. Tighten the
screws. (Fig. 5-1).
3) Check of Head Output
This check is effective only when making write and read check as described below. If the output level is
less than the prescribed output, clean the head before check.
Disk used for this check must be in good condition.
1) Load the CE Disk.
2) Select track 39.
3) Connect one of the probes of the oscilloscope to TP1 of the printed circuit board, another probe to
TP2, and the probe to ground to TP3, TP1 1(ground).
Invert one channel, and set it to Add Input, set input to AC, and set the vertical axis to 50mV/DIV and the
horizontal axis to 20msec/DIV.
4) Make sure tha average output level is the following value or more: 140 mV p-p (SN 25dB or more)
If the output is less than the above-described value, replace the head.
4) Adjustment of Positioning
1) Load CE disk.
2) Select Track 19.
3) Monitor the output in the same way as the head output inspection.
Calculate the off-track amount in reference to the calibration graph, showing the interrelation
between the burst amplitude ratio and off-track amount. (Refer to Fig. 5-2).
4) The average of amplitude ratio should be below 26 urn.
If it is not within this range, make the following adjustment,
i) Loosen the bolt of the rotation stopper which fixes the screw shaft (Fig. 6-3).
Rotate the screw shaft and adjust it in such away that the amplitude ratio may become below
15 uM. Tentatively set the bolt at that position.
ii) Make the to track step to the inner and outer circles and bring it to the original position. Make sure
that the adjustment is all right. Then, tighten the bolt.
5) Confirmation of Head Azimuth
1) Load the CE Disk
2) Select Track 39.
3) Synchronise the probe of the oscilloscope by TP9 of PCB and connect another probe to TP1 ,and
the probe ground to TP3, TP1 1(ground). Set the input to AC, the vertical axis to 1mV/DIV, and the
horizontal axis to 0.5 msec/DIV. Make sure that the two outside burst waveforms are smaller than
two inside burst waveforms as shown in Fig. 5-3.
Note: Signal preceding the azimuth burst is the index burst.
If the azimuth is still incorrect reeplace the head assembly.
15

CPC6128 MAIN PCB
m
Imcooioaj
R3?S
wmm
** vv H
i
;;gps
_LAPE
#//»:
;:|n '©?&; a'::# #«# #««ft ......
.,,. ~
.
?.
\V\W\\ Kftft?
)its #! #* erf :» «:m.# «#. #*; f|m#««tt t, <*1
ftft*
*
«aa.
:£;; -:-
Pfifii 1'' *
//diMM
,_ nRLK
trRED
R323 |£,
%%:
"2"
€1 280A
ftftftf A§HM:hh: ait 6"
•mpt
-*ns
I:
,'- :
:iSft
;'"''%;^
J__=
_" B*
"Tor
*R3QQ A''%'S
I* ft; if__
:;tf:./.';;;- :. S^'^//, pftft/Xft' -
".. •:•. ..'. 'I- .. ::; ...".' •.... ::" .. M, iMmsMm
#f #:
I? It If ft It II #
?;siiM'*s###* :*»f
Z5
r-„«,. »,
.
i-a-
+t-a-
+
*% .«!S «
jmk$i
'.. .:.......'.
:"i .: •' fk. :
.
'• "'""ft*': :.,.! .,.,.... IMj
'""/,'•'"
1>r
„{*-*- «-';
:."..-<'•''.
11C
;•.?
;-r
#'4;1,
-—
.
»- *
.. .«. .-«,,...- ««# !:> #©:« |> ;,. ,
-ft a/- "7Sjs.+. -swMjEh**:;*: .:.:*:*,,, JB'** ..J»='ft;"
_#
I
'" 1
WSk
R1U *"
R12^
J-SU&-
|«;s. Rllg
—t—--
R120
RH6
'I
c!***
NR1U1
'4$\m. m<piiim^k[%m%
f#iT!'1
,,!.:. •;::...
'*%:..#_:
Ill a•:>
:
•V,,.v'.:..',r:.5"v.'.,;...s. .,..v.:i
'i,. -r-i S|i: .=::...:: f: 'P
icfol:-
li OO
T
rv itfno ,,,-j.
i
:-"
JBL _36 26 .K
..:.. '...
*
_^JS0
.a
.'. |A
J
I^^J^:^^^^^^^!,^^!-^-^
^
-kl: R152 I
'=:. riisA: iS:.:ft*p**ai8K»p.:
<«; !«.f«t™«y^
«N«!^|i|t
R149,
R157
m*t
,«i L
I
I
t
'<: 2-J of
',/
*-11 '^# ii
a.'...' <
oyo^"-" ^#|Sis*f
aiiivplSsWp
LKS ^fc
«JTT—at ±^1L
&&&
-
_^B&k^SA±tar ^^^jjfg^^^^
*>
Ji
IC206 i:5
]S,,ik..
;:.:::;i./S:.*:*.i™*::K'>
FffT"
-. r»' jgLJ IIMI ll(n '"ri '' '
08 ;« „38 NR20I
k~i
i
1
1
ft
||i5.:5®SB
"^ •-' :-Ci«?" .. -* ".;
«!a «= ,,-i :::":.. .O ft: '; __ ..
;'. -'Sft-ftft .. !
':
:.*,:-' ;'-=;
jl *» -' -
*
^J?.. _1] i. '-3f-
gli s:..:.. ftfts:.f:::.::..; -: ?
.......ft! ftftft .-, ... ,-.;• ;,.;.;" ftpft" :"": ":-"" :. ,.:.
:""'"- ',.,..
^S^^mM,, ,ft«J '-__ .'.\_. J-' ,-- -' -,- ft •-*' j-
-_.- z- k*tl:r :|^i'*l^i f'. «^<>: f(«M(*s-:if' •.-,.' ^...R« *> "- '^
:'y'r::L::r ws,
:,-?'*»' a\ft< *,:,ft:fI):|
|P.......... .......f...r ;..:.,;.,.:,>.,.;, L.;..; .f|,i,ft,43 ':: .-«,. ....iW-ft'i:*^. .: i!- '::.:.". i» 'Sft... S.i
«08 Sl__ft "———*~ "IV*!V *I.
M:
»<ft 'ft
....„,„„ ,,»i:!.|:*::f!.ft*.|:*.| k-sJ:-i-i4m-'!^
:
\. : . ,:;'.'.::;
:
:
!
;
.
;
:. .
r
M
XX
Ae,, dSties 35
8Rt11
w
IM ¥
yft.
,!;€..
16 17

CPC6128 CPU CIRCUIT DIAGRAM
cot
ieni
zao
DATA BUS
EXPANSION BUS
NOTE:
1C 40007-X AND 1C 4OQ10
ARE ALTERNATIVES -INSTALL
ONE OR. THE OTHER BUT NOT. BOTH.
4.7K
RD. WR IORQ T
Q2X33X3U CHS-CMOS -»USE) niiiiiiiiijiiiiiiiiiiiniiiiiiiiiiiiiiiiiiiiiiiri
123 4 S67a9to 11 12 13 14 IS IB 17 IS 19 20 21 22 23 24 25 28 27 28 29 331 3233 34 35 3537 3B39 441 4243 44 45 4S 47 48 49 SO
SOUND A1S A13 All A9 A7 AS A3 A1 D7 D5 03 D1 t+5V) MlIORQ_ *R INT BU5RQ READY RESET ROMDIS RAMOIS LPEN GND _
GND A14 A12 A10 AS AG A4 A2 AO D6 D4 D2 DO MREQ RFSH RO HALT *W1 BUSAK BUS RQMEN RAMRO CURSOR EXP fl
RESET
PCS
MC0009A
CHASSIS SCHEMATIC DIAGRAM
NOTE: THIS SCHEMATIC DIAGRAM IS THE LATEST AT THE TIME
OF PRINTING AND SUBJECT TO CHANGE WITHOUT NOTICE. M208-01
1-3583
19 20

ELECTRICAL PARTS LIST
Circ. Ref. Description Part No. Circ. Ref. Description Part No.
Carbon Film Resistors IC's
47ohm R146-153, 161, 162 10020 IC101 HD74LS145 170101
56ohm R155, 306 10022 IC102 AY-3-8912 40001
82ohm R141 10030 IC103 TMM-23256P-1953 40025
150ohm R136 10036 IC104, 105, 109, HD74LS153 170103
180ohm R134 10037 113
220ohm R137 10040 IC106 HD74LS273 170104
270ohm R126, 128, 130 10042 IC107 M5L8255AP-5 170105
560ohm R317 10050 IC108 HD6845SP 170106
680ohm R125, 127, 129, 135, 157, 158, 10052 IC110, 210 HD74LS132 170107
301 IC111 Z8400APS 40080
1kohm R113, 121-123, 132, 140, 211, 10061 IC112, 207 HD74LS32 40013
212, 216, 313, 315,321 IC114 HD74LS373 170108
1k5ohm R124 10065 IC115 HD74LS244 170109
2k2ohm R102, 109, 110, 112, 214 10069 IC116 HSG3130/3170 40010
3k3ohm R131 10073 IC117 TC74HCU04P 40008/A
4k7ohm R144, 310, 323 10077 IC118 PAL 16L8AC 40031
10kohm R1 14-1 17, 120, 133, 142, 217, 10085 IC119-134 MSM3764-20RS 170110
309, 312 IC201 UPD765AC-2 40018
18kohm R308, 311 10091 IC202 FDC9216BT 170812
22kohm R118, 119,304,305 10093 IC203 SN74HC240N 170863
47kohm R302, 303, 307, 319, 320 10101 IC204 TMM-23128P-1851 40015
470kohm R314 IC205 DN74LS08 40011
1Mohm R111 10147 IC206, 208 DN74LS38 40019
3M3ohm R101 170867 IC209 DN74LS136 40016
10Mohm R143, 145 170868 IC211 DN74LS27 40012
4ohm7 1AW Fuse R322 170866 IC212 DN74LS74 40014
100ohmy2WR316 1400183 IC213
IC301 TC74HC161P LA4140 170864
170111
Ceramic Capac itors
15pF
220pF C137, 138
C139-141.310 170869
400107
IC302 LA6358S 170814
Transistors
270pF C313 170126 Q101 2SC2120Y 170113
470pF C306 24004 Q102, 301,302 2SC1815Y 170114
0.1 uF C101-135, 201-213 24020 W303 2SC950Y 170448
Electrolytic Cafjacitors Miscellaneous
1uF/50V C309, 311,314, 317, 318 20062 J101 Jack DIN 170025
22uF/10V C308 20025 J102 Socket DSub 9170023
47uF/10V C136, 303, 306 1400244 J103 Jack RCA3.5 170022
100uF/10V C301.304 20028 J104, 105 Socket IC 20 Pin DIL 170021
100uF/16V C315 20028 J106
J301 Socket IC 10 Pin DIL Jack D.C. 170865
170024
Polycarbonate Capacitors (All working voltage 5OV D.C.) J302 Jack DIN 170850
0.001 uF C312 170217 VR301 Vol. Rot. 20k 170807
0.01 uF C305 170128 CD302 D.C. Cord 170882
0.047uF
0.068uF
0.1 uF
C318
C302
C319, 320
1409178
170129
170851
CD201
FDD201 Cord Connector
Compact Floppy Disc
Drive EME-155
R. Network Exb P86222J
170862
190005
Diodes NR101 170860
D101.303, 304 1S2472-HS 170115 NR201 R. Network Exb P87681J 170861
D201 DS442XFA5 170816 RY301 Relay G4S-1 112P-1-B-19 170123
D301 10E1 170865 SP301 Speaker CO40KO1 K2451 170124
D302 SLP-155B(R) 170866 X101 Crystal HC-18RW 16MHz 170859
No part numbers are given for any parts on PCB30001 ,should there be any electrical
fault with that PCB Service Agents should return the whole Disc Drive Mechanism
complete with the PCB for replacement.
21

GT65 CABINET EXPLODED VIEW
CAUTION! PARTS MARKED
*MUST NOT BE REMOVED
UNDER NORMAL CIRCUMSTANCES
GT65 CABINET PARTS LIST
Sym Description Part No.
1Front Cabinet 170831
2Cable Clamp 170502
3Bracket Cabinet (L) 170504
4Bracket Cabinet (Ft) 170503
5Bracket P.C.B. (L) 170505
6Bracket P.C.B. (R) 170506
7CRT. Green 170507
8Metal Washer CRT. 170508
9Fixing Screw CRT. 170509
10 Deflection Yoke 170510
11 CRT Socket 170511
12 Power Tx. S/1 70832
13 Rear Cabinet 170513
14 Control Knobs 170514
15 Button Power 170515
16 On/Off Switch 170516
17 V. Hold Pot. 170833
18 Contrast Pot. 170518
19 Brightness Pot. 170519
20 D.C. Cord 170316
21 DIN Cord 170317
22 D.C. Jack 170834
23 uMetal Shield 170512/SH
22

GT65 CIRCUIT DIAGRAM GT65 VOLTAGE DATA
IC701 -UPC1031H2
1-5.99V DC
11.98V DC
10.86V DC
10.45V DC
0.61V DC
2.93V DC
5.26V DC
OV DC
9-6.0V DC
10- 11.99V DC
IC501 -L78MG
1-20.1V DC
2-OV DC
3-5.5V DC
4-5.0V DC
IC502 -L78MG
1-20.7V DC
2-OV DC
3- 12.5V DC
4-4.9V DC
ooo
uQQ
>>>
CD CD LO
CO O05
CM
O
CO
UaU
a>a
>CD >
LO CM CM
LO
O
CM
UaO
"nQ
o> o oo>
10, to o
CJiri Or- Ocm
23