Atari 820
| Atari 820 | |
|---|---|
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|
| The Atari 820, from its operator's manual | |
| Manufacturer | Atari, Inc. |
| Type | 40-column dot matrix impact printer |
| Release date | 1980[1] |
| Interface | Atari SIO, two 13-pin I/O connectors[2] |
| Compatible | Atari 400, Atari 800 and later Atari 8-bit computers[2][1] |
| Power | 120 V AC, built-in power cord; 18 W[2][1] |
The Atari 820 is a 40-column dot matrix impact printer for the Atari 400 and 800. It prints a 5 × 7 dot matrix at 12 characters per inch on plain roll paper and plugs straight into the computer's serial I/O (SIO) bus, with no interface module.[2] The comp.sys.atari.8bit FAQ gives its speed as 40 characters per second, and its 2009 edition equates it with the LRC (Eaton) 7000 printer.[3][1]
Atari previewed the 820 with the 400 and 800 at the Winter Consumer Electronics Show in January 1979 and was still promising it, at US$599.95, at the Summer CES in June 1980. The current FAQ places the first shipments, with a question mark, in the summer of 1980.[1] The 2009 edition of the FAQ has it shipping in the winter of 1980 at US$449.95 and reduced to US$299.95 in May 1981.[3] The case was designed by Roy Nishi and Russell W. Farnell.[1]
Specifications
[edit | edit source]| Item | Value |
|---|---|
| Printable area | 3 1/3 in wide |
| Characters per line | 40, at 12 characters per inch |
| Line spacing | 6 lines per inch nominal |
| Character height | 0.123 in approximately |
| Font | 5 × 7 dot matrix |
| Print cycle | 800 ms per line |
| Head sweep speed | 10.75 in/s nominal |
| Dot-to-dot cycle time | 1.3 ms |
| Print direction | Left to right |
The printer takes standard 3 7/8 inch adding machine roll paper (Atari C014062). The ribbon is Atari C014854, which the FAQ lists as the same as Addressograph/Multigraph part 116-2395-366, also used in the Eaton LRC 7000.[1]
Hardware
[edit | edit source]The main board carries a 6507 processor (A102), a 6532 RAM-I/O-timer (A103) and the program ROM (A101), with a 1 MHz crystal. The 6532 supplies 128 bytes of RAM, a timer and 16 I/O lines, which read the paper advance button and the Print OK switch, drive the motor control logic and fire the print head drivers.[2] The FAQ gives the ROM size as 2 KB.[1]
The print head has seven solenoids in a vertical row. One motor runs a belt to an elliptically slotted cam that sweeps the head across the paper and back, and the same cam advances the paper one line per revolution through an eccentric, a pawl and the ratchet teeth on the platen. A Print OK microswitch tells the processor when the head enters the print area and when it is home again, and a pawl on the head ratchets the ribbon spools round.[2]
| Position | Device | Atari part number |
|---|---|---|
| A101 | ROM | C011299 |
| A102 | 6507 processor | C010745 |
| A103 | 6532 RAM-I/O-timer | C010750 |
| A104, A105, A107 | 3086 transistor arrays | C010174 |
| A106 | Solid-state relay | C014704 |
| A108 | 78M05 regulator on heatsink | C010819 (assembly CA015323) |
| Q104 to Q110 | TIP122 solenoid drivers | C014350 |
| X101 | 1.000000 MHz crystal | C014316 |
| J103, J104 | 13-pin right-angle SIO connectors | C012995 |
| F101, F102 | 2 A type 3AG fuses | 46-2032002 |
| S102 | Print OK switch | C016732-015 |
| Print head | C016732-001 | |
| AC motor assembly | C016732-034 |
Power supply
[edit | edit source]The 820 has its own mains power supply and runs from 120 V AC through a built-in cord. Atari released it in a 120 V version only.[1] Mains feeds the transformer primary and the AC drive motor. One secondary winding feeds a bridge rectifier for the unregulated +40 V that fires the print head solenoids. The other feeds a second bridge for an unregulated +12 V, which supplies the solid-state relay and the paper advance switch, and a 78M05 regulator takes +5 V for the logic from the +12 V.[2] The solenoid drivers sink about 3.6 A when they fire.[2] Two 2 A fuses in holders on the back protect the mains input and the print head supply.[2][4]
Operation
[edit | edit source]The front panel has the power switch, the power light and a paper advance button. Each press of the button sends the head across and back and feeds the paper one line.[2] Atari's operating notes are short:[4]
- Never run the printer without a ribbon and paper fitted, or the print head solenoids can be damaged.
- Use the PAPER ADV. button to bring the head to the left-hand home position before loading paper. Do not push the head by hand.
- Turn the manual paper knob only counterclockwise, away from you. Turning it the other way or forcing it can damage it.
- The printer stops for about three seconds at intervals during long print runs to keep the head from overheating. Frequent pauses mean it is working correctly, and overriding the timeout is likely to damage it.
Known faults
[edit | edit source]Atari's troubleshooting table traces most faults to the fuses or transformer (no power light), the 6532, the transistor arrays or the solid-state relay (no paper advance, or advancing without stopping), the drive belt tension (motor stalls, uneven line feed, varying character width) and the head-to-platen gap (ribbon snagging). Error 138 on the computer points to the 6532, the 6507 or the transistor arrays.[2] Details are in the Atari 820 Troubleshooting guide. Cleaning, lubrication and the head and belt adjustments are in the Atari 820 Maintenance Guide, and the electrolytic capacitors are listed in the Atari 820 Capacitor Replacement Guide.
The 820 has mains voltage inside the case at the power cord, fuse holders, switch, transformer and motor. Unplug it before taking the top housing off.[2]
Documentation
[edit | edit source]- Atari 820 Documentation: the field service manual and the operator's manual, with contents and notes.
- ATARI 820 Printer Field Service Manual (FD100048, 1981)
- 820 Printer Operators Manual (C014762, 1979)
Gallery
[edit | edit source]-
Main board silkscreen (FD100048 appendix B) -
Power supply section of the schematic (FD100048 appendix A)
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Related pages
[edit | edit source]- Atari 820 Maintenance Guide
- Atari 820 Troubleshooting
- Atari 820 Capacitor Replacement Guide
- Atari 820 Documentation
- Atari 810
- Atari 822
- Atari 825
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Michael D. Current (ed.), Atari 8-Bit Computers: Frequently Asked Questions, comp.sys.atari.8bit FAQ, last modified 2 August 2026: section 4.1 (the Atari 820, 822 and 825 printers) and section 11.1 (history, 1979 and 1980). mcurrent.name. Community reference.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 Atari, Inc., ATARI 820 Printer Field Service Manual (FD100048, July 1981): physical description p. 1-6; specifications, table 1-1, p. 1-8; installation, chapter 2; printer timeout p. 3-3; functional description pp. 4-1 to 4-15 (power supply p. 4-8, amplifier/driver p. 4-9); maintenance, chapter 5; parts list, appendix; schematic, appendix A. Hosted here as File:Atari 820 Printer Field Service Manual FD100048.pdf.
- ↑ 3.0 3.1 Michael D. Current (ed.), Atari 8-Bit Computers: Frequently Asked Questions, last modified 29 November 2009, section 11.1 (history, 1980 and 1981). faqs.org. Community reference.
- ↑ 4.0 4.1 Atari, Inc., 820 Printer Operators Manual (C014762, 1979): setting up, printer timeout, front and back views, installing the ribbon, loading the paper. Hosted here as File:Atari 820 Printer Operator's Manual C014762.pdf.