Atari 1027 User manual

Atari 1027 Printer 5-i
Field Service Manual

Atari 1027 Printer ii
Field Service Manual
ATARI
1027TM PRINTER
FIELD SERVICE MANUAL

Atari 1027 Printer iii
Field Service Manual
Atari believes that the information described in this manual
is accurate and reliable, and much care has been taken in its
preparation. However, no responsibility, financial or
otherwise, shall be accepted for any consequences arising out
of the use of this material. Information contained herein is
subject to change. Revisions may be issued to advise of such
changes and/or additions.
Correspondence regarding this document should be forwarded to
Director of Technical Support, Consumer Product Service,
Atari, Incorporated, 845 W. Maude Avenue, Sunnyvale, CA 94086.

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Field Service Manual
TABLE OF CONTENTS
Section Title Page
INTRODUCTION v
1
THEORY OF OPERATION 1-1
Overview 1-1
User Interface 1-3
Mechanical 1-4
Case 1-4
Type Selection 1-7
Type Wheel Movement 1-7
Hammer Movement 1-7
Hammer Strike 1-7
Paper Feed 1-7
Character Sensing 1-7
Type Wheel Home Position Sensing 1-7
Hammer Home Position Sensing 1-8
Ink Roll Mechanism 1-8
Manual Knob and Paper Lock/
Release Lever 1-8
Electronic 1-8
Power Supply Circuit 1-8
Microprocessor 8049 (MPU) 1-9
Interface Circuits 1-9
Wheel, Hammer Motor Drive Circuit 1-9
Hammer Select Solenoid Drive Circuit 1-9
Character Select Solenoid Drive Circuit 1-10
DC Motor Drive Circuit 1-10
Sensor Signal Circuit 1-10
Power-on Reset Circuit 1-10
Oscillator Circuit 1-10
2
TESTING 2-1
Equipment Required 2-1
Diagnostic Procedure 2-1
Setting up the 1027 for testing and
using CPS Diagnostic Diskette with
the file T1027.BAS 2-1
Test for Character Skew 2-5
3
DISASSEMBLY/ASSEMBLY 3-1
4
SYMPTOM CHECKLIST 4-1
5
DRAWINGS AND PARTS LIST 5-1
6
SERVICE BULLETINS 6-1

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Field Service Manual
LIST OF ILLUSTRATIONS
Figure Title Page
1-1 1027 Printer Block Diagram 1-2
1-2 1027 Printer Controls/Indicators 1-3
1-3 1027 Printer Back View 1-4
1-4 1027 Printer Final Assembly 1-5
1-5 1027 Printer Mechanical Assembly 1-6
1-6 Power Supply Circuit 1-9
2-1 All Function Test Printout 2-3
2-2 Standard Character Set 2-3
2-3 International Character Set 2-4
2-4 Standard Character Set With Underline 2-4
2-5 Direction Print Check 2-4
2-6 Character Skew Printout 2-6
5-1 1027 Printer Schematic 5-3
5-2 1027 Printer Silkscreen 5-5
5-3 1027 Printer Final Assembly 5-7
5-4 1027 Printer Mechanical Assembly 5-9
LIST OF TABLES
Table Title Page
4-1 Symptom Checklist 4-1
4-2 Diagnostic Table 4-3

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Field Service Manual
INTRODUCTION
The Atari 1027TM Printer Field Service Manual is a reference
guide for the service technician. The information presented in
this manual, when used in conjunction with Atari training,
enables you to repair and maintain the 1027 Printer.
This Field Service Manual is organized in six sections:
•THEORY OF OPERATION - Overview of how the 1027 Printer
works and what its basic assemblies look like.
•TESTING - Review of tests available for diagnosing 1027
Printer problems.
•DISASSEMBLY/ASSEMBLY - Procedures for disassembling and
assembling the 1027 Printer.
•SYMPTOM CHECKLIST - Failure information to aid in
diagnosing 1027 Printer problems.
•DRAWINGS AND PARTS LIST - Silkscreen, schematic, assembly
drawings and a breakdown of parts used to repair the 1027
Printer.
•SERVICE BULLETINS - Section to be used to hold Field
Change Orders, Upgrade Bulletins and Tech Tips.

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Atari 1027 Printer 4-1
Field Service Manual
SECTION 1
THEORY OF OPERATION
OVERVIEW
The ATARI 1027TM Printer is a letter quality impact printer
that averages 10 characters per second. It is a hard copy
output peripheral intended for use under the control of the
ATARI 400TM, 800TM, 600XLTM, 800XLTM or 1200XLTM computers. It
connects directly to the SIO peripheral port of the computer
(no interface is required). The printer mechanism is a type
wheel assembly. All firmware is resident in the printer and
executed by an onboard microprocessor which controls the
functions of the printer.
Figure 1-1 on next page show a block diagram of the functional
flow of the 1027.

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Field Service Manual
Figure 1-1. 1027 Printer Block Diagram
BUFFER
BUFFER
BUFFER
BUFFER
MPU
8049
Transistor
Array
Wheel
Stepping Motor
Wheel
Stepping Motor
DATA IN
DATA OUT
COMMAND
5V/READY
Character Select
Solenoid
Hammer Select
Solenoid Driver
DC Motor
Character Select
Solenoid Driver
Hammer Select
Solenoid Driver
DC Motor Driver
Hammer Home Position
Sensor Circuit
Hammer Home
Position Sensor
Wheel Home Position
Sensor Circuit
Wheel Home
Position Sensor
Wheel Timing
Signal Circuit
Wheel Timing
Zero Timing
Signal Circuit
Zero Timing
Voltage
Regulator
AC
Adaptor
5V
6V

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USER INTERFACE
Figure 1-2 shows the location of the Controls/Indicators.
Figure 1-2. 1027 Printer Controls/Indicators
The Controls/Indicators and their functions are:
Access Door - Allows access to the plastic gears for
lubrication.
Paper Lock/Release Lever - When this lever is moved back
(direction of arrow) the paper chute opens to
allow insertion of paper. When this lever is
moved forward, there is pressure against the
platen and paper is fed.
POWER - The microprocessor is reset when the POWER button is
pressed.
Power-on Light - The LED indicates that power to the unit is
ON.
Manual Knob - Turn the manual knob to move and position the
paper in the printer.

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Field Service Manual
The back panel contains the Power Input Jack and two
Input/Output (I/O) connectors (See Figure 1-3).
Figure 1-3. 1027 Printer Back View
Mechanical
This section describes the mechanical characteristics of the
1027 Printer. For an overall understanding of the 1027
printer. operation, read both this section and the Electronic
Section which follows the mechanical. Use Figure 1-4 and
Figure 1-5 as reference for the following discussion.
Case
The outer case is composed of four pieces of plastic. The
pieces are: 1) the upper case; 2) the lower case; 3) the
bezel; and, 4) the cover.

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Field Service Manual
Figure 1-4. 1027 Printer Final Assembly

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Field Service Manual
Figure 1-5. 1027 Printer Mechanical Assembly

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Field Service Manual
**MECHANICAL REFERENCES MADE HERE ARE FOR ELECTRONIC VERIFICATION ONLY.**
Type Selection
The DC motor drives the main gear (on the spring clutch
assembly) via the idle gear to rotate the type wheel shaft and
the type wheel assembly. When the desired type comes into
position facing the hammer, Solenoid A is turned on and the
type wheel select lever stops the type wheel shaft.
Type Wheel Movement
The wheel select pulse motor assembly is linked to the type
wheel assembly by a wire via the wheel select pulley assembly
to move the wheel back and forth along the type wheel shaft.
Hammer Movement
The hammer pulse motor assembly is linked to the hammer
assembly by a wire via the hammer move pulley assembly to move
the hammer assembly back and forth along the hammer shaft.
Hammer Strike
The DC motor rotates the type wheel shaft via the idle gear
which rotates the cam attached to the type wheel shaft, hammer
lever (A) and hammer lever (B) to strike the hammer.
Paper Feed
The DC motor rotates the type wheel shaft via the idle gear,
which rotates the cam attached to the type wheel shaft, the
paper feed lever and the rubber roller linked to the lever to
feed paper.
Paper is fed only when the concave part of the timing cam and
the convex part of the paper feed lever face each other (blank
type is selected).
Character Sensing
The type and the reference postion of each type are detected
by the photosensor (sensor (A) unit)* through the sensor plate
assembly mounted on the same shaft as the type wheel.
Type Wheel Home Position Sensing
The home position of the type wheel is detected by the
photosensor (sensor (A) unit)* through the sensor plate
assembly mounted on the type wheel.
*Sensor (A) contains more than one photosensor.

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Field Service Manual
Hammer Home Position Sensing
The home position of the hammer assembly is detected by the
photosensor as the shutter plate mounted on the hammer
assembly moves into and out of the sensor.
Ink Roll Mechanism
The ink roll manually snaps onto the plastic post in front of
and parallel to the type wheel.
Manual Knob and Paper Lock/Release Lever
When the manual knob is pushed in and turned clockwise it
rotates the rubber roller (which is gear-linked to the manual
knob) to feed paper forward. Counter-clockwise rotation feeds
the paper in the reverse direction.
When the paper lock/release lever is moved back (direction of
arrow), the paper chute opens to allow insertion of paper.
When this lever is moved forward, the friction roller presses
against the platen and paper is fed.
ELECTRONIC
The 1027 Printer electronics consists of 10 elements which are
discussed in the following paragraphs:
•the Power Supply Circuit
•the Microprocessor 8049 (MPU)
•the Interface Circuits
•the Wheel, Hammer Motor Drive Circuit
•the Hammer Select Solenoid Drive Circuit
•the Character Select Solenoid Drive Circuit
•the DC Motor Drive Circuit
•the Sensor Signal Circuit
•the Power ON Reset Circuit
•the Oscillator Circuit
Power Supply Circuit
The main power supply is an external AC Adaptor rated at 9.5V
@ 40VA. Regulated outputs are obtained through a 3-terminal
regulator in the main unit.
The power supply system consists of:
Vc 5V ± 5% for the logic circuit and for the sensor circuit.
Vp 6V ± 10% for driving the pulse motors, DC motor and
solenoids

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Field Service Manual
Figure 1-6. Power Supply Circuit
Microprocessor 8049 (MPU)
The MPU is an N-MOS custom microprocessor with a built-in 2K
ROM, a 128-byte RAM and a clock circuit. Most of the IC pits
are used as I/O ports.
Interface Circuits
The unit uses a serial interface. The serial port consists of
a serial DATA OUT (transmission) line, a serial DATA IN
(receiver) line and other miscellaneous control lines.
Wheel, Hammer Motor Drive Circuit
The transistor array LB1259 has active high inputs in the
equivalent circuit. The wheel select pulse motor and the
hammer pulse motor are stepper motors driven by 2-phase
excitation. Clock pulses to the motor are approximately 5
msec.
Hammer Select Solenoid Drive Circuit
Solenoid B, the hammer select solenoid, is controlled by a
single pulse input of approximately 10 msec from P21 (pin 22)
of the MPU.

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Field Service Manual
Character Select Solenoid Drive Circuit
Solenoid A, the character select solenoid, is controlled by a
single pulse input of approximately 8 msec. from P20 (pin 21)
of the MPU.
The character select signal goes High at the rising edge of
wheel timing and goes Low after approximately 3 msec of the
next rising edge of wheel timing.
DC Motor Drive Circuit
While the signal is Low at P22 (pin 23) of the MPU, the DC
motor keeps rotating. Sensor Signal Circuit
The sensor of this circuit consists of a photo diode and a
photo transistor. The circuit composed of the buffer and two
resistors (IOK, 22K) is a Schmitt trigger circuit.
Power ON Reset Circuit
When the printer power switch is turned on, the MPU is reset
by the power ON reset circuit. At power ON, the capacitor is
charged to give a Low steal to the MPU RST (pin 4) terminal
for a moment. After approximately 100msec. the RST terminal
goes High.
Oscillator Circuit
The MPU uses an external quartz oscillator which determines
the operation frequency.
The oscillation frequency is 6 MHz ± 0.3%.

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Field Service Manual
SECTION 2
TESTING
Equipment Required
•An Atari Computer and accessories
•A BASIC language cartridge
•An Atari Disk Drive
•CPS Diagnostic Diskette with the file T1027.BAS (P/N
FD100577, Rev. 02)
•A 15 MHz oscilloscope
•A Digital Voltmeter
•A precision screwdriver kit
•A Soldering Iron
Diagnostic Procedure
The testing procedures available for the 1027 are:
•CPS Diagnostic Diskette with the file T1027.BAS.
•A test for character skew which consists of a BASIC
Program which you will type in.
CAUTIONS: USE ONLY GOOD QUALITY 81/2 X 11 STANDARD UNLINED
PAPER. DO NOT USE ROLL PAPER.
DO NOT USE LABELS OR ANY ADHESIVE - BACKED MATERIAL. NEVER
PRINT WITHOUT PAPER IN THE PRINTER.
The following pages explain how to set up the 1027 for testing
and contain procedures and sample printouts for each test.
Setting up the 1027 for testing and using CPS Diagnostic
Diskette with the file T1027.BAS.
1. Connect the computer to the TV set as shown in the
computer owner's manual.
2. Plug the 1027 into the power adaptor.
3. Plug an I/O cable into the computer and the 1027.
4. Connect the disk drive to the computer as shown in the
owner's manual.
5. Power up the 1027 Printer. Wait for the printer to
complete its initialization. During initialization the
Type Wheel Assembly moves to the left end of the
carriage, the Type Wheel Assembly rotates, then moves a
short distance to the right and stops.
6. Power up the disk drive. Wait for the disk drive to
complete its initialization.
7. Insert the CPS Diagnostic Diskette with the file
T1027.BAS into the disk drive and close the door.

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Field Service Manual
8. Insert the BASIC cartridge into the computer (if
applicable).
NOTE: This program requires the use of BASIC to execute. Later
model computers may have BASIC already installed.
9.Turn on the computer and TV set. Wait for the computer to
complete its initialization. TV display should exhibit
"READY" in white letters on a blue background.
10.Enter the command RUN "D1:Tl027.BAS" and terminate with
the RETURN key.
11.The program will now load and execute. 12. The following
menu appears:
TEST FACILITY
FOR THE
1027 PRINTER
REV. 2
1) ALL FUNCTION TEST
2) STANDARD CHAR SET
3) INTERNATIONAL CHAR SET
4) UNDERLINE CHECK
5) DIRECTION PRINT CHECK
6) CARRIAGE RETURN LOOP
7) HORIZONTAL STEP MOTOR LOOP
8) SELECTIVE CHAR PRINT LOOP
Q) STOP TEST AND RETURN TO MENU
PLEASE SELECT AN OPTION
Select 1) for the printout illustrated in Figure 2-1. This
test runs continuously until Q is pressed to stop the test and
return to the menu.

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1027 PRINTER FUNCTION TEST, PASS # 1
STANDARD CHAR SET
!”#$%&’()*+-0123456789:;,=.?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_'abcdefghijklmno
pqrstuvwxyz
INTERNATIONAL CHAR SET
áùÑÉçôí₤ïüäÖúÜâûîéèñêåàÅ↑↓←→ ! ”#$%&’()*+-0123456789:;,=.?@ABCDEFGHIJKLMNOPQR
STUVWXYZ[\]^_'abcdefghijklmnopqrstuvwxyzÄ
STANDARD CHAR SET WITH UNDER-LINE
!”#$%&’()*+-0123456789:;,=.?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_'abcdefghijklmno
pqrstuvwxyz
DIRECTION PRINT CHECK
00000000011111111112222222222333333333344444444445555555555666666666677777777778
12345678901234567890123456789012345678901234567890123456789012345678901234567890
END OF TEST
Figure 2-1. All Function Test Printout
Select 2) to print the standard character set. This option
prints the standard character set except for CONTROL N and
CONTROL O. This test runs continuously until Q is pressed to
stop the test and return to the menu. Figure 2-2 illustrates
the standard character set.
STANDARD CHAR SET
!”#$%&’()*+-0123456789:;,=.?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_'abcdefghijklmno
pqrstuvwxyz
Figure 2-2. Standard Character Set
Select 3) to print the International character set. This
option prints the International character set except for
CONTROL N and CONTROL O. This test runs continuously until Q
is pressed to stop the test and return to the menu. Figure 2-3
illustrates the International character set.
INTERNATIONAL CHAR SET
áùÑÉçôí₤ïüäÖúÜâûîéèñêåàÅ↑↓←→ ! ”#$%&’()*+-0123456789:;,=.?@ABCDEFGHIJKLMNOPQR
STUVWXYZ[\]^_'abcdefghijklmnopqrstuvwxyzÄ
Figure 2-3. International Character Set