AMSTRAD DMP1 User manual

AMSTRAD COMPUTER SYSTEM
FIELD SERVICE
TRAINING AND SERVICE GUIDE
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CPC464 10 CONNECTIONS
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USER PORTS
PRINTER
5vV DOC
MONITOR
PADDLE
PORT
CONNECTOR
(9
PIN
DI
VIEWED FROM REAR
PIN
1
UP
PIN
6
FIRE
2
PIN
2
DOWN
PIN
7
FIRE
1
PIN
3
LEFT
PIN
8
COMMON
PIN
4
RIGHT
PIN
3
COM
2
PIN
5
SPARE
VIDEO
OUTPUT
CONNECTOR
'6
PIN
DIN)
VIEWED FROM REAR

REAR PANEL AND CONNECTIONS TO CPC-464
EXPANSION
PORT
50
WAY
0.1
EDGE
CONNECTOR
VIEWED FROM REAR
PRINTER
PORT
34
WAY
0.1
EDGE
CONNECTOR
VIEWED FROM REAR
35
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330
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REAR PANEL AND CONNECTIONS TO CPC-464
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SOUND
GENERATOR
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== SOUND
TO EXP
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STEREQ iE
SOUND + _____1_
CONNECTOR
{sterce pack)
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SYSTEM POWER UP SEQUENCE
For
correct
system
operation
it
is
imperative
that
the
peripherals
are
turned
ON
in
a
set
order,
i.e.
If
the
computer
is
powered
on
before
the
disk
drive,
any
accesses
to
the
disk
drive
will
cause
the
computer
to
crash,
because
the
interface
has
not
been
correctly
initialized.
An
indication
of
the
above
system
fault
is
by
the
appearance
of
Red
dots
in
the
top
LH
corner
of
the
screen,
on
a
monochrome
monitor
the
dots
will
be
slightly
brighter
than
the
background.
The
correct
power
up
sequence
is:-
1 DISK DRIVE
ae MONITOR or MP1
as COMPUTER
4. PRINTER

SYSTEM SPECIFICATIONS
COMPUTER
Z80A Microprocessor Running at 4 MHz
64K Bytes of RAM (43533 bytes available)
32K Bytes of ROM (contains Basic and Operating System)
6845 Cathode Ray Tube Controller (CRTC)
8255 Parallel I0 Port (controlling the keyboard, cassette motor
and sound generator chip)
AY-3-8912 3 Voice, 7 Octave Sound Generator IC (also contains an
8 bit I0 port which is used to scan the keyboard).
20RAD43 Gate Array (replaces 90% of the TTL logic in the
computer)
DATA CASSETTE
4.75cm per second tape speed (1 7/8 ips) standard audio speed
DATA STORED in 2Kbyte blocks.
3" Floppy Disk can be reversed to provide data storage on two
sides.
40 Tracks per Side
9 Sectors per Track
512 Bytes per Sector
180 Kbytes Total Formatted Storage Space Per Side
Disk Rotational Speed of 300 RPM

PRINTER
Print Method
Print Direction -
Character Matrix
Characters
Character Code
Dot Spacing
Character Pitch
Character Columns
Print Speed
Line Feed Spacing
Line Feed Speed
Graphics
Multiple Copies
Paper Width
SYSTEM SPECIFICATION
Impact Dot Matrix
Unidirectional (left to right)
S(width) x 7(height) + 1(space)
128
upper/lower
case
characters,
numerals
and
symbols
7 Bit ASCII
1/60" (H) x 1/63" (V)
10 Characters/Inch
80 Columns-Character Mode
480 Dot Columns-Graphics Mode
50 Characters/Second
6 Lines/Inch-Character Mode
9 Lines/Inch-Graphics Mode
10 Lines/Sec (at 6 lines/inch)
15 Lines/Sec (at 9 lines/inch)
Any
combination
of
7
dots
in
a
vertical
column
Two Including Original
(thickness 0.15mm or less)
4.5 to 10 Inches Acceptable
(pin to pin 4 to 9.5 inches)
10

THE KEYBOARD
The
Amstrad
keyboard
contains
some
special
keys
which
aid
program
entry
and
debugging.
Some
of
these
may
be
familiar
to
experienced
computer
users.
The
following
is
a
list
for
those
who
are
not
familiar
with
the
action
of
the
keys.
ENTER
There
are
two
ENTER
keys.
Either
of
these
keys
enter
the
information
that
you
have
typed
into
the
computer.
After
the
ENTER
key
is
pressed,
a
new
line
is
started
on
the
screen.
Each
instruction
that
you
type
in
to
the
computer
should
be
followed
by
pressing
the
ENTER
key.
DEL
This
key
is
used
to
delete
a
character
to
the
left
of
the
cursor
on
the
screen
(for
example
a
letter
or
a
number)
which
is
not
required.
Type
abcd
and
you
will
see
that
the
letter
d
is
positioned
to
the
left
of
the
cursor.
If
you
decide
that
you
do
not
want
the
letter
d,
press
DEL
once
and
you
will
see
the
d
removed.
If
you
press
DEL
and
continue
to
hold
it
down,
the
letters
abc
will
also
be
removed.
SHIFT
There
are
two
SHIFT
keys.
If
you
press
either
of
these
and
hold
it
down
whilst
typing
a
character,
a
capital
letter
or
upper
case
symbol
will
appear
on
the
screen.
Type
in
the
letter
a
then
hold
down
the
SHIFT
key
and
type
in
the
letter
a
again.
On
the
screen
you
will
see:
aA
Now
type
in
a
few
spaces
by
holding
down
the
space
bar.
Try
the
following
using
the
number
keys
which
are
on
the
top
line
of
the
keyboard,
above
the
letter
keys.
Type
in
the
number
2,
then
hold
down
the
SHIFT
key
and
type
in
the
number
2
again.
On
the
screen
you
will
see:
Qo"
You
can
now
see
what
happens
when
the
SHIFT
key
is
held
down
whilst
pressing
a
character
key.
Experiment
by
typing
any
of
the
character
keys,
either
on
their
own,
or
together
with
the
SHIFT
key.
11

THE KEYBOARD
CAPS LOCK
This has a similar operation to SHIFT except that you only have
to press it once. From then on each letter that you type in wil]
be in capitals, although the number keys will not be shifted.
Press CAPS LOCK once, then type in:
abcdef 123456
On the screen you will notice that although all the letters are
shifted to capitals, the numbers have not been shifted to
symbols. If you wish to type in a shifted symbol while CAPS LOCK
is in operation, simply hold down the SHIFT key before pressing a
character key, Press the following keys while holding down the
SHIFT key:
ABCDEF 123456
On the screen you will see:
ABCDEF!"#$%&
If you wish to return to small (lower case) characters again,
press CAPS LOCK key once again.
If you wish to type in capital letters and shifted upper case
symbols without having to constantly hold down the SHIFT key,
this can be carried out by holding down the CTRL key, then
pressing CAPS LOCK key once. Now type in:
abcdef1l23456
On the screen you will see:
ABCDEF!"#$%&
It is still possible to type in numbers while CTRL and CAPS LOCK
are in operation, by using the number keys to the right of the
main keyboard.
Holding down the CTRL key and pressing CAPS LOCK once will return
you to the mode that you were previously in - CAPS LOCK or lower
case. If you have returned to the CAPS LOCK mode, simply press
CAPS
LOCK
once
again
to
return
to
the
lower
case
mode.
CLR
This key is used to clear a character within the cursor.
Type
in
ABCDEFGH.
The
cursor
will
be
positioned
to
the
right
of
the
last
letter
typed
(H).
Now
press
the
cursor
left
key
——
four
times.
The
cursor
will
have
moved
four
places
to
the
left,
superimposed
over
the
top
of
the
letter
E.
12
rm

THE KEYBOARD
Notice how the letter E is still] visible within the cursor.
Press the CLR key once and you will see that the letter E has
been cleared and the letters FGH have each moved one space to the
left with the letter F now appearing within the cursor. Now
press the CLR key again and hold it down. You will see how the
letter F is cleared followed by the letter G and H.
ESC
This key is used to ESCape from a function that the computer is
in the process of carrying out. Pressing the ESC key once will
cause the computer to temporarily pause in its function, and wil]
continue again if any other key is pressed.
Pressing the ESC key twice will cause the computer to completely
ESCape from the function which it is carrying out. The computer
is then ready for you to type in some more instructions.
Now press the ESC key twice.
IMPORTANT
When
you
reach
the
right
hand
edge
of
the
display
by
entering
more
than
40
characters
on
the
screen,
the
next
character
will
automatically
appear
on
the
next
line
at
the
left
edge
of
tne
screen.
This
means
that you
should
NOT
press
ENTER
as those
of
you
accustomed
to
typewriters
might
press
a
carriage
return
towards
the right
edge
of
a
page.
The
computer
does this
automatically
for
you,
and
will
react
to
an
unwanted
ENTER
by
printing
an
error
message
-
usually
a
Syntax
error,
either
there
and
then,
or
when
the
program
is
run.
pine
The
above
key
symbols
represent
the
four
cursor
control
keys,
they
have
two
different
functions.
1.
By
depressing
any
one
of
the
keys
the
cursor
will
move
in
the
direction
indicated.
2.
By
holding
down
the
shift
key
whilst
pressing
one
of
the
cursor
keys
the
computer
will
enter
the
edit
mode
(two
cursors
on
the
screen).
In
this
mode
program
lines
may
be
edited
or
corrected.
COPY
This
key
is
used
in
conjunction
with
the
cursor
control
keys
(in
edit
mode),
by
depressing
the
COPY
key
program
lines
may
be
copied
and
edited,
this
facility
is
mainly
used
to
correct
mistakes
in
program
lines.
13

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THE KEYBOARD
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14

HE DATA CASSETTE
When
the
program
has
been
typed
in,
and
corrected,
it
will
have
to
be
stored,
otherwise
when
the
computer
is
turned
off
the
program
will
be
erased
from
memory.
The
CPC464's
inbuilt
cassette
deck
provides
a
cheap
storage
medium.
This
deck
uses
standard
audio
tapes
of
up
to
C90
in
length,
never
use
cheap
tapes
as
these
tend
to
lose
their
oxide
easily
resulting
in
corrupt
data
(it
only
takes
one
corrupt
bit
of
data
to
stop
a
program
from
loading).
The
programs
are
saved
in
blocks,
each
block
can
be up
to
2000
bytes
in
length,
the
computer
can
be
programmed
to
save
data
to
the
cassette
at
two
different
speeds,
the
tape
speed
stays
the
same
(4.75cm
per
second
or
1
7/8
IPS),
the
frequency
at
which
the
data
is
written
is
changed.
The
commands
are;
SPEED WRITE O
Data
is
saved
at
1000
bits
per
second,
this
represents
the
data
speed
selected
when
the
computer
is
turned
on.
SPEED WRITE 1
The
data
rate
is
doubled
up to
2000
bits
per
second,
as
some
of
the
safety
margins
are
sacrificed
when
using
this
option,
it is
important
that
high
quality
tapes
are
used,
also
differences
in
azimuth
between
machines
may
affect
the
loading
if
the
program
is
loaded
on
a
different
machine
to
the
one
it
was
saved
on.
The
computer
automatically
sets
itself
to
read
the
data
rate
at
which
the
tape
was
recorded.
Special
commands
are
used
to
control
the
cassette
deck.
The
most
common
ones
are
shown:
-
Press
CTRL
and
the
small]
BLUE
ENTER
keys
together
to
load
the
first
program
off
cassette.
LOAD
"Program
Title"
loads
a
named
program
into
memory
from
the
cassette.
SAVE
"Program
Title"
saves
a
program
from
memory
to
the
cassette
tape
(Program
Title
cannot
be
more
than
16
character
in
length).
CAT
This
command
catalogues
the
programs
on
the
cassette
tape,
an
ok
at
the
end
of
the
file
name
indicates
that
the
file
is
readable.
15

TYPICAL SYSTEM FAULTS
Normal System - Yellow characters on blue background.
System Faults . No power, LED extinguished.
-LED illuminated but No video.
No characters on the screen except a border.
Rubbish on screen.
No vertical or horizontal sync.
CPC464 powers up okay, but will not load
cassette programs.
CPC464 powers up and loads program but they
‘crash' when run (may be solid or intermittent
fault).
Keyboard faulty.
In the following fault finding description, if the computer is at
fault it must be uplifted and sent to the workshop for repair.
The Amstrad computer system requires both on/off switches to be
turned on before it will operate, an indication as to whether
power has reached the computer is the illumination of the RED
LED.
The 5 volt DC power rail for the computer originates from the
monitor. The monitor HT rail has to be working correctly before
the computers 5v rail is established. This 5v rail contains an
over current protection circuit, so a short circuit in the
computer will turn off the 5 volts.
The 5 volts can be measured by removing the DC plug to the
computer and measuring from inner to outer.
The 5 volts is again switched by the computers own on/off
switch, once this is in the ON position and the 5 volts is
established, the Red power LED should illuminate.
If the LED DOES NOT ILLUMINATE then check the 5v DC going to the
computer, if there is 5v DC going into the computer measure the
resistance of the 5v DC computer rail at the internal connections
of the DC socket, on the 2 K Ohms diode range the circuits
resistance should be around 400 Ohms. A reading lower than 300
Ohms will indicate a short, an open circuit will indicate a
faulty on/off switch or cassette plug connection.
If there is no 5v DC present, the fault lies in the mains plug,
the monitor, or the 5v DC coiled lead. Check the existance of
the monitors HT rails for if these are not correct, the 5v DC
rails will not function. Normal fault finding principles apply
to the mono and colour monitors. °
16

TYPICAL SYSTEM FAULTS
If the LED DOES illuminate check for video on the monitor. The
normal display is yellow characters on a blue background. If the
display is correct, run the field diagnostic tape.
If no video is present, then'check the output voltages of the
video socket, the correct DC voltages are shown below.
Faults causing NO SYNC or lack of either vertical or horizontal
sync may be associated with the computer or monitors. Check the
sync amp transistor Q601 in the mono monitor. Memory faults with
the computer can cause some strange and varying sync faults.
Cassette will not load if the motor is turning, clean the
record/play head, load the field diagnostic tape. If it stops
between blocks or fails to load you may have a RAM fault.
The field diagnostic will automatically run when loaded. If it
does not run correctly or displays FAULT FOUND, the computer is
at fault. Allow the program to cycle through before declaring
the computer operational. The keyboard and data cassette can be
tested by running the programs on the other side of the cassette.
VIDEO DISPLAY AT POWER UP
YELLOW
CHARACTERS
ON
BLUE
BACKGROUND
os

TYPICAL SYSTEM FAULTS
CHECKING THE CPC-464 CIRCUIT RESISTANCE
i. ue ” ar a ot i ae
MEASURING
THE
CPC-464
MONITOR
SOCKET
OUTPUT
(BLUE)
18

AMSTRAD CPC464 VIDEO OUTPUT
NORMAL VIDEO OUTPUT AT POWER ON
All voltages are D.C. and measured with respect to chassis (GND).
19

THE DMP1 PRINTER
Connecting the printer to the computer.
io
Check that both the DMP1 printer and the CPC-464 computer are
switched off.
The connector at the rear of the DMP1 is a Centronics-style
socket, which you should find easily distinguishable from the
PCB edge connector used at the rear of the CPC-464.
The DMP1 is supplied complete with a cable that allows direct
connection to the PRINTER connector at the rear of the CPC-
464. The diagram below shows how this cable is to be fitted.
Firm pressure will be required to ensure that a good
connection is made.
After connecting the Centronics-style plug into the rear
socket of the DMP1, lock the plug into position by pressing
the metal clips either side of the socket into the cut-outs
at the side of the plug.
DMP1 Printer
QE=====/)
Connector
to
the
CPC464
Connector
to
the
DMP-1
(PCB
Edge
connector)
(Centronics-style
plug)
TO
tim
End
marked
1
|
Connector ;
Overhead view
Rear of the CPC464 computer

DIP SWITCH SELECTION
You will find the DIP switches on the rear panel of the DMP1,
next to the Centronics-style connector socket.
You will receive the DMP] set by the factory for UK language
characters -(see table below). This will enable you to use
programs which incorporate the £ sign, such as home budgeting and
accounting programs.
You should note however, that when listing programs incorporating
the # sign, it will be printed as §&.
If at any time you wish to print # signs, simply set DIP switch
No.3 off (down). It should then be noted, that under this
condition, £ signs will be printed as #.
Setting DIP switch No.4 on (up), will result in double line
spacing by the printer, as opposed to the normal single line
spacing.
DIP switches 1, 2 and 3 are used to select eight different
language characters as follows.
Code (HEX)
| 24 5B/5C 15D 7B|7C|7D|7E sw | SW2| SW3
Country
U.S.A, $ ile OFF Jore| LOFE.
UK.
$
|
|OFF
OFF
ON
GERMANY # | $ A|Oj}U ON |OFF
sieoen | «[x[@|[o |x] oe [® on on
FRANCE | ae Ae a 4 ON OFF OFF
DENMARK | # | $ | @ [AE] ® A|* 7 ON |OFF| ON
tia
ths
{
_|
ITALY #/1$/1@l° i \le Pee aloleli ON | ON |OFF
|/— settle =
SPAIN | Pt [8 @/i {Niello} cle ~ ON | ON
21

PRINTER TROUBLESHOOTING GUIDE
Use
the
table
below
to
diagnose
any
problems
that
may
occur.
PROBLEM
CAUSE
AND
REMEDY
The DMP1 does not print Vs
The DMP1 does not print.
The POWER LED is on.
The DMP] is operating correct-
ly but the paper is not feed-
properly.
The print is faint or smeared.
22
Power
is
not
getting
to
the
DMP1
Check
the
Mains
Lead
is
connected
and
the
ON/OFF
switch
is
ON.
The
Fuse
in
the
Mains
Plug
may
be
blown
-
Replace it with a 3 Amp Fuse.
The connection to the computer
is not correct -
Check to make sure that the
cable between the printer and
the computer is correctly
connected.
The ribbon cassette is not
properly installed -
Correctly install the ribbon
according to the instructions in
the book.
The paper is jammed in the
printer -
Remove the paper and reload it
correctly.
The print head position is not
correct -
Set the head adjustment lever to
match the type of paper being
used.
The ribbon cassette is not
properly installed -
Correctly install the ribbon
according to, the instructions in
the book.

PRINTER TROUBLESHOOTING GUIDE
The ink ribbon is worn -
Replace the ribbon.
The
POWER
LED
is
flashing
on
_
An
error
condition
has
occurred
and
off.
due
to
the
detection
of
abnormal
timing
in
a
sensor
-
Switch
power
off,
wait
approx.
10
seconds,
then
switch
on
again.
If
the
fault
persists,
send
the
complete
system
to
the
workshops.
SETTING THE HEAD POSITION
The
print
head
position
is
adjusted
using
the
Head
Adjustment
lever
on
the
left
hand
inside
wall
of
the
printer.
It
should
be
set
according
to
the
thickness
of
paper
being
used.
The
diagram
below
shows
the
8
different
setting
positions
of
the
lever
which
are
indicated
by
the
position
of
the
lever
foot
in
the
click
holes.
Red mark
Head
adjustment
lever
Lever
foot
The
settings
graduate
from
position
|
for
very
thin
paper,
to
position
8
for
thicker
paper.
Position
3,
indicated
by
a
red
arrow
above
the
Head
Adjustment
slot,
is
suitable
for
general
purpose
computer
paper,
including
Amsoft:
Printer
Paper.
During
insertion
or
removal
of
the
paper
or
ribbon
cassette,
the
Head
Adjustment
lever
should
be
set
fully
towards
the
front
of
the
printer
(past
position
8).
The
tinted-perspex
printer
cover
can
now
be
lowered
backwards
to
its
closed
position,
ready
for
operation.
Keeping
the
cover
closed
will
help
reduce
noise,
and
keep
the
printer
mechanism
dust
free.
to
23