AMSTRAD PC1640 User manual

IBM
PC1640
PERSONAL COMPUTER
PC-MD
MONOCHROME DISPLAY
PC-CD
COLOUR DISPLAY
PC-ECD
ENHANCED COLOUR DISPLAY
SERVICE MANUAL

CONTENTS
Technical Specification
Safety Tests
FD-3 Maintenance
Flow Charts
Hard Disc Installation Instructions
Switch Settings
Understanding bad sectors on ahard disc
Notes
Keyboard Exploded Diagram
Keyboard Control PCB Layout
Keyboard Schematic Diagram
PC1640 Electrical Parts List
PC1 640/SD/DD/HD20 Cabinet Drawing &Parts List
PC1640/SD/DD/HD20 CPU P.C. Board
PC1 640/SD/DD/HD20 CPU P.C. Board (Bottom View)
PC1640/SD/DD/HD20 Chassis Schematic Diagram
PC1 640/SD/DD/HD20 Chassis Schematic Diagram
PC1640/SD/DD/HD20 Chassis Schematic Diagram
PC1640/SD/DD/HD20 Chassis Schematic Diagram
PC1640/SD/DD/HD20 Chassis Schematic Diagram
PC1 640/SD/DD/HD20 Chassis Schematic Diagram
PC-MD Electrical Parts List
PC-MD Cabinet &Parts List
PC/MD Main/CRT/Volume P.C. Board
PC/MD Chassis Schematic Diagram -Power Supply
PC-MD Chassis Schematic Diagram
PC-MD Alignment Instructions
PC-CD Electrical Parts List
PC-CD Electrical Parts List
PC-CD Alignment Instructions
PC/CD Chassis Schematic Diagram •
PC/CD Chassis Schematic Diagram
PC/CD Main P.C. Board
PC/ECD Cabinet &Parts List
PC-ECD Electrical Parts List
PC-ECD Alignment Instructions
PC-ECD RGB P.C. Board
PC/ECD CRT P.C. Board
PC-ECD Relay P.C. Board
PC/ECD Main P.C. Board
PC/ECD Chassis Schematic Diagram
PC/ECD Chassis Schematic Diagram -
PC/ECD Chassis Schematic Diagram
Monitor
Power Supply
Monitor
-TTL Decoder
Power Supply
Monitor
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TECHNICAL SPECIFICATION
Internal Graphics Adaptor, fully compatible
640K system unit with all circuitry on asingle motherboard
8MHz 8086 processor
Three full-size compatible expansion slots (even with hard disc
option)
One or two 360K 5'A" floppy disks or one floppy with a20
Megabyte hard disk drive.
RS232 serial and parallel interface with standard connectors.
Loudspeaker with volume control.
Battery back-up real time clock and configuration RAM.
Socket for 8087 maths co-processor
Connector for light pen and/or joystick.
Full sized keyboard.
Numlock and Capslock.
Keyboard joystick port.
Two-button mouse with dedicated port on system unit.
Choice of one of three displays (paper-white mono, colour,
enhanced colour) with standard video connector.
ECD monitor has .31 mm pitch shadow mask.
CD monitor has .42mm pitch shadow mask.
Internal Graphics Adaptor provides:
Mono(MD):
80 column high resolution text with 9x14 dot characters.
EGA compatible Monochrome graphics 640 x350 lines.
Colour (CD):
(for use with CGA and 200-line EGA software)
40/80 column text with 8x8 dot characters in 16colours.
Medium resolution graphics 320 x200 lines in 4colours.
High resolution colour graphics 640 x200 lines in 2or 16col^
Enhanced Colour (ECD):
40/80 column text with 8x14 or 8x8dot characters in 16
colours.
High resolution colour graphics 640 x200 lines in 2or 16
colours.
Extra-high resolution graphics 640 x350 lines in 16 out of 64
colours.
oIum^
Dimensions (approx):
Monitors (Unboxed)
PC-MD
PC-CD
PC-ECD
System Unit
Gross Weights (approx):
Monitors
PC-MD
PC-CD
PC-ECD
System Unit
PC-SD
PC-DD
PC-HD
WIDTH
350mm
370mm
370mm
370mm
HEIGHT
315mm
320mm
320mm
135mm
(Boxed) 9.0Kg
13.5 Kg
13.5 Kg
DEPTH
300mm
360mm
360mm
384mm
(Unboxed)
8.0Kg
11.5Kg
11.5Kg
(Boxed) (Unboxed)
8.9Kg
10.5 Kg
11.0Kg
Keyboard (Boxed with
system unit)
5.0Kg
5. 8Kg
e^QKg
SAFETY TEST
All monitors are tested to the following specifications.
1.Flash Test: Test at 1.5kV RMS /3sec between the live and neutral poles of the mains lead and
all accessible metal points on the exterior of the set.
2. Insulation Resistance Test: Test at 1.5kV RMS /3sec between the live and neutral poles of the
mains lead and all accessible metal points on the exterior of the set to show aresistance greater
than 4Mohms.
3. Earth Continuity Test: The resistance of the mains lead shall not exceed 0.5ohms.
PLEASE NOTE: When any work is completed on this unit, correct safety tests must be carried out
to ensure continued electrical safety.
PLEASE NOTE: All parts shown with the part number prefix /'\ are Safety Items and must be
replaced with similar items having an identical safety specification.
All those items may be purchased direct from AMSTRAD pic.
AMSTRAD PLC
BRENTWOOD HOUSE, 169 KINGS ROAD, BRENTWOOD, ESSEX CM14 4EF.
TELEPHONE: [phone]. TELEGRAMS: AMSELEC BRENTWOOD. TELEX: 995417 AMSELE G.
In keeping with our policy of continually improving our service, and the technical quality of our products, we reserve the right to change component types,
manufacturers, sources of supply or technical specification at any time.

ittist
yv
NOTE
The flow charts 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 unit the 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. Alps and Tandon. When ordering the
replacement units make sure that the Part No. is either 175037 for the Alps drive or 60001 for the 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.
FD3 MAINTENANCE
1. Introduction
This maintenance manual is for the maintanance FD3
1-1 General
The floppy disk Drive is ahigh precision equipment and requires the following Special Jigs, Tools, measuring
instruments and Adjustment when repairing or changing parts.
2. Special Jigs, Tools and Measuring Instruments
2-1 List of Special Jigs and Tools
CE diskette Dysan 224/2A
Blank diskette
Cleaning diskette
2-2 List of Measuring Instruments
Oscilloscope
Brian
Frequency Counter
2-3 CE Diskette (Alignment Diskette)
This Diskette is used for the following adjustments and checks.
R/W head radial position
R/W head azimuth
Index burst timing
3. Diagnosis Procedure
3-1 General
Hard errors are often caused by an incorrect procedure erroneous programing or damaged diskette, and soft
errors are often caused by dirty air or random electric noise. And other external factors are often considered to
be drive failure or incorrect adjustment. Check that errors are repeatedly produced with the first diskette and
that similar errors are also produced with other diskettes, unless obvious assembly trouble or 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 out by the liner in the diskette.
2) Random electrical noise less than several microseconds.
3) Delicate track misalignment and writing timing misalignment, these are not detected during writing, and may
cause soft errors during reading.
4) Incorrect ground of the drive or host system power supply.
5) Incorrect spindle 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 recovered.
2) Access the head to an adjacent track if the error is not recovered by step (1) then return the head to the
previous track.
3) Repeat step (1).
4) Recalibrate the head then access the previous track and repeat step (1).
5) An error 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 the drive is responsible for the error. If the
same error occurs on another track, change the diskette and repeat these steps. If the error still occurs, the
drive has some fault. If the error does not occur, the diskette is defective.
3-4 Read Error
Most errors are soft errors. Data can be recovered by following the recovery steps 3-2.
3-5 Seek Error
If seek error occurs, recalibrate the head then access target track once more.
If seek error occurs again, the drive has some faults.
Most seek errors are caused by stepping motor trouble or stepping motor drive circuit trouble.
3-6 Compatibility Error
In some cases, data written by one drive cannot be read by another drive.
This is due to the following reasons:
The check points are listed below.
1) Incorrect 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 Fig. 3-7)
Test Point Signal Name rTP 9-—-4-
r111r1
1
TP1 READ AMP OUT
+
TP2 READ AMP OUT
-
TP3 GND
TP4 STEP
TP5 READ DATA
TP6 INDEX
TP7 WRITE PROTECT
TP8 TRACK 00
TP9 GND
I
Fig. 3-7 Test Point Layout
4. Parts Exchange
4-1 Printed Circuit Board Exchange (See Fig. 4-1)
4-1-1 Printed Circuit Board Removal
a)
b)
c)
d)
e)
Remove the drive belt, stretched between the spindle pulley and the DC motor pulley by rotating the spindle
pulley as the direction shown in Fig. 4-1. Be careful not to touch the inner surface of the drive belt and the side of
the spindle pulley and DC motor pulley.
Disconnect the connectors. (LED, P.C.B., Track 00 sensor, DC Motor P.C.B., Stepping Motor, Head F.P.C.).
Unfasten four printed circuit board fixing screws.
Remove the printed circuit board.
Remove the insulating sheet.
Fig. 4-1 Printed Circuit Board Exchange
*
4-1-2 Printed Circuit Board Mounting and Adjustment
a) Install the insulating sheet.
b) Fix the printed circuit board with four screws.
c) Reconnect the disconnected connectors, (LED, P.C.B., Track 00 sensor, DC motor P.C.B., Stepping motor,
Head F.P.C.).
d) Place the drive belt over the DC motor pulley completely and only partially on the spindle pulley.
e) By rotating the spindle pulley, the rest of the belt will fit completely over.

4-2 DC Motor P.C.B. Removal (See Fig. 4-2)
4-2-1 DC Motor P.C.B. Removal
a) Disconnect the connectors (Printed Circuit Board, DC Motor)
b) Unfasten two DC motor P.C.B. fixing screws.
c) Lift the right edge of the DC motor P.C.B. and pull it up.
Be careful not to touch the spindle pulley with DC motor P.C.B.
4-2-2 DC Motor P.C.B. Mounting and Adjustment.
a) Install the DC motor P.C.B.
b) Fix the DC motor P.C.B. with two screws.
c) Reconnect the disconnected connectors. (Printed Circuit Board, DC Motor).
Fig. 4-2 DC Motor P.C.B. Removal
4-3 Lever Exchange (See Fig. 4-3)
4-3-1 Lever Removal
a) Set the lever horizontally.
b) Unfasten the fixed screw of the lever.
c) Pull the lever forward.
4-3-2 Lever Mounting
a) Place the wide part of the clamp 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.
Fig. 4-3 Lever Exchange

4-4 Bezel Exchange (See Fig. 4-4)
4-4-1 Bezel Removal
a) Remove the lever as described in 4-3-1.
b) Unfasten two bezel fixing screws.
c) Pull the bezel forward.
4-4-2 Bezel Mounting
a) Insert the bezel from the front.
b) Secure the bezel with two screws.
c) Mount the lever as described in 4-3-2.
Fig. 4-4 Bezel Exchange
4-5 LED Assembly Exchange (See Fig. 4-5)
4-5-1 LED Assembly Removal
a) Disconnect the connectors. (Index sensor, W/P sensor and Printed Circuit Board).
b) Unfasten the LED Assembly fixing screw.
c) Pull it back.
4-5-2 LED Assembly Mounting and Adjustment
a) Install the LED Assembly by inserting the LED into the LED insertion hole on the bezel.
b) Fix the LED Assembly with a screw.
c) Reconnect the disconnected conectors. (Index sensor, W/P sensor and Printed Circuit Board).
Fig. 4-5 LED Assy Exchange

4-6 Ejector Assembly Exchange (See Fig 4-6)
4-6-1 Ejector Assembly Removal
a) Set the lever vertical (Clamp state).
b) Unfasten three cover fixing screws.
c) Remove the cover.
d) Insert protection paper (High quality white paper approximately 10x30 mm between the top head and bottom
head to protect them.
e) Unfasten two ejector assembly fixing screws.
f) Lift the top head carefully, (approximately 2-3mm) then remove the ejector assembly.
4-6-2 Ejector Assembly Mounting and Adjustment.
a) Lift the top head and insert the ejector assembly under the head arm.
b) Place the ejector assembly as two half punched bosses fit into the holes of the lever frame then secure the
ejector assembly with two screws.
c) Remove the protect sheet between the top head and bottom head.
d) Fix the cover with one short screw and two long screws.
(Short screw for inner hole).
m
AMI
Fig. 4-6 Ejector Assembly Exchange
4-7 Lever Frame Assembly Exchange (See Fig. 4-7)
4-7-1 Lever Frame Assembly Removal
a) Remove the lever as described in 4-3-1
.
b) Remove the bezel as described in 4-4-1.
c) Remove the LED assembly as described in 4-5-1
.
d) Remove the ejector assembly as described in 4-6-1
.
e) Unfasten four lever frame fixing screws.
f) Lift the lever frame assembly slightly making sure that the top head is not raised, and remove the lever frame
assembly by sliding it to the left.
4-7-2 Lever Frame Assembly Mounting and Adjustment
a) Lift the top head slightly and slide the pad mounting arm of the lever frame assembly under the top head.
b) Secure the lever frame assembly with four screws.
c) Mount the ejector assembly as described in 4-6-2.
d) Mount the LED assembly as described in 4-5-2.
e) Mount the bezel as described in 4-4-2.
f) Mount the lever as described in 4-3-2.
g) Turn the lever slowly until it stops. By this operating, the hub assembly is placed in the best position for
clamping automatically.
h) Adjust the index burst time. (Refer to 5-5).

Fig. 4-7 Lever Frame Assy Exchange #
Head Assembly Removal
Remove the lever as described in 4-3-1
.
Remove the bezel as described in 4-4-1.
Remove the LED assembly as described 4-5-1.
Remove the ejector assembly as described in 4-6-1.
Remove the lever frame assembly as described in 4-7-1
.
Disconnect the connectors (Head F.P.C.)
Unfasten the screws fixing the guide shaft keeper Aand B, then remove keeper Aand B.
Hold the bottom head and lift the head assembly slightly then carefully remove by sliding to the right.
Remove the guide shaft from the head assembly in backward direction.
Head Assembly Mounting and Adjustment
Insert the guide shaft into head assembly and mount on the chassis so that the follower pin of the head
assembly fits into the screw of the screw shaft of the stepping motor assembly by sliding to the left.
Secure guide shaft keeper Aand Bwith two screws.
Reconnect the disconnected connectors (head F.P.C).
Mount the lever Frame assembly as described in 4-7-2.
Mount the ejector assembly as described in 4-6-2.
Mount the LED assembly as described in 4-5-2.
Mount the bezel as described in 4-4-2.
Mount the lever as described in 4-3-2.
Adjust the radial track alignment (5-2), index burst time (5-5), trackOO sensor timing (5-3), head azimuth (5-4),
resolution (5-7) and symmetry (5-8) after head mounting.
8
Fig. 4-8 Head Assy Exchange

4-9 Stepping Motor Assembly Exchange (See Fig. 4-9)
4-9-1 Stepping Motor Assembly Removal
a) Remove the lever as described in 4-3-1.
b) Remove the bezel as described in 4-4-1.
c) Remove the LED assembly as described in 4-5-1.
d) Remove the ejector assembly as described in 4-6-1.
e) Remove the lever frame assembly as described in 4-7-1.
f) Remove the head assembly as described in 4-8-1.
g) Disconnect the connector (stepping motor).
h) Unfasten two stepping motor fixing screws.
i) Remove the stepping motor assembly. Be careful not to touch the screw shaft of the stepping motor.
4-9-2 Stepping Motor Assembly Mounting and Adjustment
a) Install the stepping motor assembly in the chassis, and fix with two screws.
b) Reconnect the disconnected connector (stepping motor).
c) Mount the head assembly as described in 4-8-2.
d) Mount the lever frame assembly as described in 4-7-2.
e) Mount the ejector assembly as described in 4-6-2.
f) Mount the LED assembly as described in 4-5-2.
g) Mount the bezel as described in 4-4-2.
h) Mount the lever as described in 4-3-2.
i) Adjust the radial track alignment (5-2), index burst time (5-5), trackOO sensor timing (5-3), head azimuth (5-4),
resolution (5-7) and symmetry (5-8) after mounting.
*
«tk
Fig £-9 Stepping Motor Assy Exchange
4-1 DC Motor Assembly Exchange (See Fig. 4-1 0)
4-10-1 DC Motor Assembly Removal
a) Remove the drive belt as described in 4-1-1 a)
b) Disconnect the connector (DC Motor)
c) Unfasten two DC motor assembly fixing screws.
d) Remove the DC motor assembly.
4-10-2 DC Motor Assembly Mounting and Adjustment
a) Secure the DC Motor assembly with two screws.
b) Reconnect the disconnected connector (DC Motor).
c) Replace the drive belt as described in 4-1-2 d), e).
d) Adjust the spindle speed (5-1) after mounting.

Fig. 4-10 DC Motor Assy Exchange
4-1
1
TrackOO Sensor Assembly Exchange (See Fig. 4-1 1)
a) Unfasten three cover fixing screws.
b) Remove the cover.
c) Disconnect the connector (trackOO sensor).
d) Unfasten trackOO sensor assembly fixing screws
e) Remove the trackOO sensor assembly
4-1 1-2 TrackOO Sensor Assembly Mounting and Adjustment
a) Mount the trackOO sensor assembly with ascrew.
b) Reconnect the disconnected connector (trackOO sensor).
c) Fix the cover with one short screw and two long screws, (short screw for inner hole)
d) Adjust the trackOO sensor after mounting (refer to 5-3).
^
Fig. 4-11 TrackOO Sensor Assy Exchange
10