AMSTRAD PC1512 User manual

I
PC1512
PERSONAL COMPUTER
PC-MM
MONOCHROME MONITOR
PC-CM
COLOUR MONITOR
SERVICE MANUAL

CONTENTS
Safety Note
Technical Specification
Servicing Note
FD-3 Flow Chart
FD-3 Flow Chart
FD-3 Servicing Information
FD-3 Exploded View
Cabinet Diagram Exploded View & Parts List
Electrical Parts List
Cabinet Diagram Exploded View
CPU P.C.B. Assembly Component Side
Exploded View CPU Unit
Hard Disc Installation Instructions
Alignment Instructions PC-CM
Alignment Instructions PC-MM/PC1512
Cabinet Diagram &Parts List PC-CM
Cabinet Diagram &Parts List PC-MM
Chassis Schematic Diagram
Keyboard Schematic Diagram &P.C.B. Layout
Keyboard Exploded View
Chassis Schematic Diagram PC-MM
Chassis Schematic Diagram
Chassis Schematic Diagram
Chassis Schematic Diagram PC-MM Monitor
Chassis Schematic Diagram
PC-CM Power Supply
PC-CM Main PCB Component Layout
PC-CM Main PCB Component Layout
CRT PC Board, Colour Monitor
Schematic Diagram FD-3 CPU
Page
2
2
3
3
4-6
7- 14
15
16& 17
18-20
21
22 &23
24
25
26
27
28
29
30-33
34&35
36
37
38
39
40
41
42
43
43
44
TECHNICAL SPECIFICATION
51 2K system unit with all circuitry on asingle motherboard.
8MHz 8086 processor.
Memory expandable on motherboard to 640K.
Integral colour graphics adaptor with special 16 colour hi-res
mode.
Three full-size compatible expansion slots with power available
in the standard unit to supply a hard disc and controller.
Choice of one or two 360K 51A" floppy discs or one floppy with a
1or 20 megabyte hard disc drive.
HARD DISC VERSIONS ARE SUPPLIED WITH AN EXTRA
FLOPPY DISC AND MANUAL WITH BACKUP, RESTORE AND
FORMAT UTILITIES.
Motherboard includes an RS232c serial and parallel interface
with standard connectors.
Loudspeaker with volume control.
Battery-backed real time clock and configuratioon RAM.
Socket for 8087 maths co-processor.
Connector for light pen.
Complete with Colour Monitor or Monochrome (Grey Level)
Monitor.
The standard built-in colour adaptor provides all the following
modes.
Medium resolution Alpha; 16 colours, 40x45 characters.
High resolution Alpha; 16 colours, 80x25 characters. .^
Medium resolution Graphics; 2colour, Three 4-colour pallettes,
320x200 pixels.
High resolution Graphics; 2colour, 640x200 pixels.
-FSpecial high-res Graphics; 16 colours, 640x200 pixels.
Full size QWERTY keyboard.
Illuminated Numlock and Capslock.
Keyboard joystock port.
Extra DEL-» and ENTER keys.
Two button Mouse with
Dedicated port on system unit.
Microsoft compatible MOUSE.COM plus special text operation.
DIMENSIONS (all in mm)
PC1 51 2SD System unit 372(w) x384(d) x135(h) 6.05Kg
PC1512DD System unit 372(w) x384(d) x135(h) 7.75Kg
Keyboard Unit inc feet 465(w) x160(d) x58(h) 1 .1 75Kg
PC-MM Monochrome Monitor 350(w) x300(d) x31 5(h) 7.43Kg
PC-CM Colour Monitor 372(w) x365(d) x330(h) 11.6Kg
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 pic
BRENTWOOD HOUSE, 169 KINGS ROAD, BRENTWOOD, ESSEX CM14 4EF.
TELEPHONE; 0277 230222. TELEX: 995417 AMSELE G.

NOTE
THE FLOWCHARTS ARE FOR INFORMATION ONLY AND FOR WARRANTY PURPOSES ANY FAULTY
DRIVE MECHANISM MUST BE RETURNED TO AMSTRAD FOR REPLACEMENT. SERVICE AGENTS
SHOULD NOT ATTEMPT TO REPAIR THE MECHANISM.
SERVICE AGENTS SHOULD NOTE THAT THE HARD DISC UNITS ARE THE MOST SOPHISTICATED
MECHANISMS AND SHOULD NEVER BE OPENED IN ANORMAL ENVIRONMENT. IF ANY ATTEMPTS
ARE MADE TO OPEN THE HARD DISC UNITTHE GUARANTEE IS THEN INVALIDATED AND AMSTRAD
TAKES NO RESPONSIBILITY TO EXCHANGE THE DRIVE.
YOU SHOULD NOTE FURTHER THAT THERE ARE TWO TYPES OF HARD DISC UNITS IN USE
i.e. XEBEC AND TANDON. WHEN ORDERING THE REPLACEMENT UNITS MAKE SURE THAT THE
PART NO. IS EITHER 171663/X FOR XEBEC DRIVE OR 171663/T FOR TANDON DRIVE. THIS
INFORMATION APPLIES ONLY TO THE 20MB DRIVES.
AMSTRAD RESERVES THE RIGHT TO AMMEND THE CIRCUIT OR CHANGE THE COMPONENTS
WITHOUT PRIOR WARNING.
USE RP4 DIAGNOSTICS EXPANSION CARD OR DIAGNOSTIC DISC FOR FAULT FINDINGS.
FD-3 SERVICE INFORMATION
1. Introduction
This section is for the maintenance of DFC222A.
1-1 General
The floppy disk drive is ahigh precision equipment and requires the following jigs, tools, measuring
instruments, and adjustments when repairing or changing parts.
2. Special Jigs, Tools and Measuring Instruments
2-1 List of Special Jigs and Tools
CE diskette
Blank diskette
Test pin connector
Alignment adjusting jig
Otrack adjusting jig
2-2 List of Measuring Instruments
Oscilloscope
Brikon
Frequency counter
2-3 CE Diskette (Alignment Diskette)
This diskette is used for the following adjustments and inspection.
(1) R/W head radial position
(2) R/W head azimuth
(3) Index position

Trouble
3£
See error command
of FDC.
See this maintenance
maunal to other
mechanical troubles.
NO
YES ->-
Nn
YES ->- Change LED
V
Is write protect
signal received?
Medium may be
damaged. •-YES —
NO
Does it write if
medium is changed?
Y
NO
Cannot
write
YES-
\/
Is write
protect seal stuck
on medium?
NO
Y
YES
Write protect sensor has
failed. Check write
protect circuit and its
periphery.
J
Is head cord damaged
or disconnected?
V
NO
Remove seal
YES
Exchange head
Is write gate
correctly opened?
YES
_L_
Is setting
appropriate?
YES
NO
NO
Check circuit
check system
Drive NG
(stepping motor)
Check circuit

±
Is termination
resistor correctly
attached?
NO Mount
correctly
YES
1_
Is environment
condition appropriate? NO Set up environmental condition appropriately
YES
Are errors
caused after changing
to another medium?
NO Medium may
be faulty
YES
Is avery
large noise source
present?
YES Remove noise
source
NO
Is tlkere
&
Is there
sufficient head
head pressure
NO
NO Change head
YES
Are errors
caused on inner
circumference of
tracks?
NO
YES
Is spindle
speed OK? NO
YES
Is index
signal correctly sent? NO Adjustment
YES
\l/
Is azimuth
azimuth NO Tilting of guide shafts
due to shock, or heads
are defective
YES
Is seek
operation
normal?
NO >Check step motor and
driving mechanism
YES
Is time margin
of inner circumference
tracks sufficient?
YES
A
NO
YES
^_
^L
Change the printed
circuit board. Change
the head if problem
is not solved.
Is power NO Check power
ripple noise
correctly fed?
Check data separator
on system side
YES
v
Check circuit
(Read errors are caused)

FD-3 FLOWCHART
Are connectors
correctly plugged? NO .. Plug correctly
r> Medium may
be faulty
YES
NO ^
Is short bar
setting correctly?
Set normally
>
YES
YES
YES
sk_
Does it read
if changed to
another medium?
NO
Is alignment
OK?
YES
Is spindle
speed OK?
YES
1_
Is index signal
sent correctly?
YES
XL.
Is TRKOO OK?
YES
Is motor start
time appropriate?
YES
Is medium
rotating?
NO-
J1L.
Does cariage
operate properly? NO. Check step motor
and circuit head
driving mechanism
operating step
motor.
YES
Does read
waveform show
after adjustment?
YES Adjustment,
NO
NOi
V
NO
V
NO
Read circuit may
have problems.
Change MC3470AP.
Change printed
circuit board.
V
NO
V
Over-
speeding?
YES
Check motor
control printed
circuit board. Is
servo cord
disconnected
from motor?
V
Is index sent?
YES
Index sensor
is faulty
Adjust
NO
V
-NO
Change motor
alignment
3l
Read circuit has
aproblem.
Exchange
MC3470AP.
Change printer
circuit board.
XL.
Operating
normally?
Possibility of
or head cord
trouble.
Adjust
X-
Adjust
V
Can it be
adjusted?
V
NO
NO
XL
Is power fed? NO Check power
YES
A
Does DC motor
operate?
(Apply 12V)
NO^ Change DC motor *
YES
J/ NO^
Are cords
and wires correctly
connected?
Correct
incorrect wiring.
YES
-YES
IOK Is motor ON
signal sent? NO. Check signal on
system side
YES
*_
Possibility of circuit
part faults. Adjust
centering motor-control
printed circuit board.
W
-YES- OK
Drive has problem
(Medium slip or
other reason).

3. Diagnosis Procedure
3-1 General
Errors caused by an incorrect operating procedure, erroneous programming, damaged diskette,
and sott errors caused by dirty air, random electric noise, and other external factors are often
considered to be drive failures or incorrect adjustments. Check that errors are repetitively
produced with the first diskette and that similar errors are also produced with other diskettes,
unless obvious assembly trouble and damage are found in visual inspection.
3-2 Soft Error Detection and Correction
Soft errors are generally caused by the following.
(1) Dirty air between the R/W head and disk. Normally, this dirt is cleaned by the liner in the diskette.
(2) Random electrical noise less than several microseconds.
(3) Delicate track misalignment and writing timing misalignment that are not detected during
writing may cause soft errors during reading.
(4) Improper ground of the drive or host system power supply.
(5) Improper motor speed.
The following actions are required on the control side to recover the foregoing soft errors.
(1) Reread the track ten times or until data recovers.
(2) Access the head to an adjacent track in the same direction as the track if the error is not
recovered by Step 1. Then return the head to the previous track.
(3) Repeat Step 1.
(4) Errors that cannot be recovered after taking these steps cannot be recovered.
3-3 Write Error
Operate READ-AFTER-WRITE if an error occurs during the write operation.
If the error cannot be recovered after operating READ-AFTER-WRITE more than four times,
operate READ-AFTER-WRITE on another track to determine whether the diskette or drive is
responsible for the error. Change the diskette and repeat these steps if the same error remains. If
the error still remains, the drive has some fault and if the error is erased, the diskette is defective
and should be discarded.
3-4 Read Error
Most errors are soft errors. Data can be recovered by following the error recovery steps (3-2).
3-5 Seek Error
(1) Trouble with the stepping motor or stepping motor drive circuit.
(2) Carriage trouble.
Seek error is recovered by system soft. There are two recovering ways.
(1) Recalibrate
(2) Detect ID field
3-6 Compatibility Error
In some cases, data written by one drive cannot be read by another drive. This is dur mainly to the
following reasons:
The check points are listed below.
(1) Improper head alignment —5-2
(2) The head output is low —5-6
(3) Motor speed irregularity —5-1
(4) Check if the recommended sector format is set up.
3-7 List of Test Points (see figure 3-7)
Test Point Signal Name
TP1 AMP OUT +
TP2 AMP OUT-
TP3 GND
TP4 STEP
TP5 READ DATA
TP6 INDEX
TP7 WRITE PROTECT
TP8 TRACK
TP9 GND
3
Fig. 3-7 Test Point Layout

4. Parts Exchange
4-1 Printed Circuit Board Exchange (See Figure 4-1)
4-1-1 Printed Circuit Board Removal
a) Expand the two shield board pins and cord holder pin.
b) Unfasten the three fix screws and remove the shield board.
c) Disconnect the connectors (head, stepping motor, spindle motor, track sensor, index sensor, and
write protect sensor).
d) Unfasten the three printed circuit board fix screws.
e) Moves '.he head to inner about 10mm.
f) Lift the rear edge of the printed circuit board and pull it back.
4-1-2 Printed Circuit Board Mounting and Adjustment
a) Tilt the printed circuit board as if to lower the front edge, insert the front LED into the LED
insertion hole on the front plate, then lower the rear edge.
b) Fix the printed circuit board with three screws.
c) Secure the shield board with three fix screws.
d) Reconnect the disconnected connectors (head, stepping motor, spindle motor, track sensor,
index sensor, and write protect sensor).
e) Bend the two shield board pins and fix the head cable.
f) Check the spindle speed (5-1), radial track (5-2), track sensor (5-3), azimuth (5-4), index burst
time (5-5), level (5-6), resolution (5-7), symmetry (5-8) and write protect sensor (5-9) after mounting.
Note: Insert the head cord under the shield board and fix at the same routing as before exchange.
Fig. 4-1 Printed Circuit Board Removal
4-2 Lever Exchange (See Figure 4-2)
4-2-1 Lever Removal
a) Set the lever horizontally.
b) Unfasten the fix screw of the lever.
c) Pull the lever forward.
4-2-2 Lever Mounting
a) Place the wide part of the lever cam on the hub side and check that the lever shaft hole can be
seen from above. (Hub open state).
b) Set the lever horizontally and insert from the front.
c) Secure the lever with ascrew.
4-3 Front Plate Exchange (See Figure 4-3).
4-3-1 Front Plate Removal
a) Remove the lever as described in 4-2-1.
b) Unfasten the two front plate fix screws.
c) Pull the front plate forward. ^
4-3-2 Front Plate Mounting
a) Insert the front plate from the front.
b) Secure the front plate with two screws.
Mount the lever as described in 4-2-2.
4-4 Eject Assembly Exchange (See Figure 4-4)
4-4-1 Eject Assembly Removal.
a) Make the lever vertical (clamp state).
b) Remove the printed circuit board as described in 4-1-1.
c) Insert protection paper (high quality white paper approximately 10x30 mm) between the heads
to protect them.
d) Unfasten the two Eject Assembly fix screws.
e) Lift the top head (approximately 2-3mm), and remove the Eject Assembly.
4-4-2 Eject Assembly Mounting and Adjustment.
a) Lift the top head and insert the Eject Assembly under the Head Arm.
b) Adjust the position of eject assembly that the ejector lock when the diskette is inserted and the
diskette is ejected when the lever is operated and secure the eject assembly with two screws.
c) Remove the protection paper.
d) Mount the printed circuit board as described in 4-1-2.
8

Ilj^
4-5 Lever Frame Assembly Exchange (See Figure 4-5)
4-5-1 Lever Frame Assembly Removal
a) Remove the printed circuit board as described in 4-1-1.
b) Remove the lever as described in 4-2-1.
c) Remove the front plate as described in 4-3-1
.
d) Remove the eject assembly as described in 4-4-1.
e) Unfasten the four lever frame assembly fix screws.
f) Lift the lever frame assembly slightly making sure that the top head is not raised, and remove the
slidinh to the left.
4-5-2 Lever Frame Assembly Jvlounting and Adjustment.
a) Lift the top head slightly and slide the pad mounting part of the lever frame assembly under the
top head.
b) Secure the lever frame assembly with four screws.
c) Mount the eject assembly as described in 4-4-2.
d) Mount the front plate as described in 4-3-2.
e) Mount the lever as described in 4-2-2.
f) Unfasten the two screws of hub shaft holder and centre by moving the hub up and down several
times and secure the two screws.
g) Mount the printed circuit board ad described in 4-1-2.
h) After mounting, adjust the index burst time. (Refer to 5-5).
4-6 Stepping Motor Assembly Exchange (See Figure 4-6)
4-6-1 Stepping Motor Assembly Removal
a) Remove the printed circuit board as described in 4-1-1.
b) Unfasten the head assembly metal belt fix screw.
c) Unfasten the stepping motor belt fix screw and remove the keep plate.
d) Unfasten the two stepping motor assembly fix screws.
e) Lift the stepping motor assembly upward, then slide it to the left to remove from the metal belt.
f) Disconnect the stepping motor assembly cord from the hook.
4-6-2 Stepping Motor Assembly Mounting Adjustment
a) Keep the metal belt in the loop form, insert the stepping motor assembly, mount the metal belt
and keep plate with screws.
b) Align the oval hole of the stepping motor mounting plate with the guide pin and mount the
stepping motor assembly with two screws.
Temporary tightening of screws are required.
c) Pull the tip of the metal belt and mount the metal belt on the tip of the head assembly with ascrew.
d) Move the head assembly back and forth and check that the metal belt is not twisted. If twisted,
slightly loosen the metal belt fix screws on the stepping motor assembly and head assembly, and
move the head assembly back and forth several times.
Fasten the screws tightly.
e) Place the stepping motor assembly cord on the hook.
f) Mount the printed circuit board as described in 4-1-2.
g) Adjust the radial track after mounting. (Refer to 5-2).
Caution: Do not reuse the metal belt removed from the head assembly.
4-7 Head Assembly Exchange (See Figure 4-7)
4-7-1 Head Assembly Removal
a) Remove the printed circuit board as described in 4-1-1.
b) Remove the lever as described in 4-2-1
.
c) Remove the front plate as described in 4-3-1.
d) Remove the eject assembly as described in 4-4-1.
e) Remove the lever framne assembly as described in 4-5-1
.
f) Remove the stepping motor assembly as described in 4-6-1.
g) Unfasten the PCB post fix screws and remove the PCB post.
h) Unfasten the two screws fastening the guide shaft keepers Aand Band remove keepers Aand B.
i) Lift the guide shaft rear edge and remove the guide shafts in abackward direction, individually. Be
careful not to damage guide shafts or mix the right and left shafts.
j) Carefully remove the head assembly.
4-7-2 Head Assembly Mounting and Adjustment
a) Fit the two guide shafts in the head assembly without mixing the right and left, and mount in the
housing while holding the guide shaft.
b) Secure guide shaft keepers Aand Busing four screws.

c) Secure the PCB post using screws.
d) Mount the stepping motor assembly as described in 4-6-2.
e) Mount the lever frame assembly as described in 4-5-2.
f) Mount the eject assembly as described in 4-4-2.
g) Mount the front plate as described in 4-3-2.
h) Mount the lever as described in 4-2-2.
i) Place the printed circuit board as described in 4-1-2.
j)Adjustthe radial track(5-2) and index burst time (5-5), and checktheO track sensor(5-3),
azimuth (5-4), level (5-6), resolution (5-7) and symmetry (5-8) after mounting.
4-8 Spindle Motor Assembly Exchange (See Figure 4-8)
4-8-1 Spindle Motor Assembly Removal
a) Remove the printed circuit board as described in 4-1-1.
b) Remove the lever as described in 4-2-1.
c) Remove the front plate as described in 4-3-1.
d) Remove the eject assembly as described in 4-4-1.
e) Remove the lever frame assembly as described in 4-5-1
.
f) Unfasten the four spindle motor fixing screws (three screws on top and one screw on
the bottom).
g) Remove the spindle motor in adownward direction. Be careful not to damage the top surfaces of
the spindle.
4-8-2 Spindle Motor Assembly Mounting Adjustment
a) Secure the spindle motor with four screws. Align the W/P LED approximately the
centre of the housing hole.
b) Mount the lever frame assembly as described in 4-5-2. ^
c) Mount the eject assembly as described in 4-4-2.
d) Mount the front plate as described in 4-3-2.
e) Mount the lever as described in 4-2-2.
f) Place the printed circuit board as described in 4-1-2.
g) Adjust the spindle speed (5-1 ), radial track (5-2), track sensor (5-3) and index burst time (5-5)
and check the azimuth (5-4), level (5-6), resolution (5-7), symmetry (5-8) and write protect sensor (5-
9) after mounting.
4-9 Track Sensor Assembly Exchange (See Figure 4-9)
4-9-1 Track Sensor Assembly Removal
a) Remove the printed circuit board as described in 4-1-1.
b) Unfasten the track sensor assembly fix screw.
c) Remove the track sensor assembly.
4-9-2 Track Sensor Assembly Mounting and Adjustment.
a) Mount the track sensor assembly with screws.
Temporary tightening of screws is required.
b) Place the printed circuit board as described in 4-1-2.
c) Adjust the track sensor after mounting. (Refer to 5-3).
4-10 Metal Belt Exchange (See Figure 4-10) ^
4101 Metal Removal
a) Remove the printed circuit board as described in 4-1-1.
b) Remove the lever as described in 4-2-1.
c) Remove the front plate as described in 4-3-1.
d) Remove the eject assembly as described in 4-4-1.
e) Remove the lever frame assembly as described in 4-5-1.
f) Remove the stepping motor assembly as described in 4-6-1.
g) Remove the head assembly as described in 4-7-1.
h) Unfasten the metal belt fix screws and remove the metal belt from the head assembly.
4102 Metal Belt Mounting and Adjustment
a) Mount the metal belt on the head assembly using screws. (Be careful of the metal belt direction).
b) Mount the head assembly as described in 4-7-2.
c) Mount the stepping motor assembly as described in 4-6-2.
d) Mount the lever frame assembly as described in 4-5-2
e) Mount the eject assembly as described in 4-4-2.
f) Mount the front plate as described in 4-3-2.
g) Mount the lever as described in 4-2-2.
h) Mount the printed circuit board as described in 4-1-2.
i) Adjust the radial track (refer to 5-2), index burst time (5-5), and track sensor (5-3) after mounting.
10