Editing Atari 1027 (section)

== Hardware ==

Atari's ''1027 Printer Field Service Manual'' (FD100670 Rev. 01, October 1983) describes the mechanism and electronics.<ref name="fsm">Atari, Inc., ''1027 Printer Field Service Manual'', FD100670 Rev. 01, October 1983. Theory of operation (pp. 1-1 to 1-10); testing (pp. 2-1 to 2-6); disassembly and preventive maintenance (pp. 3-1 and 3-2); symptom checklist and diagnostic table (pp. 4-1 to 4-3); schematic, silkscreen and parts list (pp. 5-3 to 5-11). Hosted here as [[:File:Atari 1027 Printer Field Service Manual FD100670 Rev 01.pdf]].</ref>

=== Mechanism ===

A DC motor turns the type wheel shaft through an idle gear. When the wanted character faces the hammer, solenoid A (character select) stops the wheel. A wheel select stepper moves the wheel along its shaft by a wire and pulley, and a hammer stepper moves the hammer to match; a cam on the type wheel shaft then fires the hammer and, when a blank is selected, advances the paper through a rubber roller. Photosensors read each character position, the type wheel home position and the hammer home position. The ink roller snaps onto a post in front of the type wheel.<ref name="fsm" />

=== Electronics ===

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Main parts (FD100670 parts list, p. 5-11)'''
! Location !! Part !! Atari part number
|-
| A1 || 8049 microprocessor, custom, with 2 KB ROM and 128 bytes of RAM || FC100619
|-
| A2 || 14050 hex buffer || FC100629
|-
| A3 || 74LS09 || FC100632
|-
| A4 || 17806P regulator (6 V) || FC100611
|-
| A5 || 17805P regulator (5 V) || FC100612
|-
| A6 || LB1259 transistor array || FC100630
|-
| C1 || 15,000 µF 25 V capacitor || FC100627
|-
| D1 || Rectifier || FC100628
|-
| XTL1 || 6 MHz crystal || FC100631
|-
| IR2 || Ink roll || FC100626
|-
| ADP || AC adaptor || FC100623
|}

The adaptor is rated 9.5 V at 40 VA. The board rectifies it and regulates two rails: Vc, 5 V ±5 %, for the logic and sensors, and Vp, 6 V ±10 %, for the stepper motors, DC motor and solenoids.<ref name="fsm" /> The FAQ lists the adaptor as 9.5 V AC, 4.2 A, Atari CO61636.<ref name="faq" /> Atari's schematic shows a 5 A fuse inside the adaptor.<ref name="fsm" /> The LB1259 drives the two steppers with two-phase excitation and clock pulses of about 5 ms; solenoid B (hammer select) takes a pulse of about 10 ms and solenoid A (character select) one of about 8 ms. The power-on reset holds the 8049 for about 100 ms, and the crystal runs at 6 MHz ±0.3 %.<ref name="fsm" />