Atari 810
| Atari 810 | |
|---|---|
 |
|
| Atari 810 with the original MPI mechanism and pull-down door | |
| Manufacturer | Atari, Inc. |
| Type | 5.25-inch floppy disk drive |
| Release date | Previewed January 1979; shipping from late 1979[1] |
| Interface | Atari SIO, two 13-pin I/O connectors[2] |
| Compatible | Atari 400 and Atari 800 with at least 16 KB of RAM; later Atari 8-bit computers[2][1] |
| Successor | Atari 1050 |
| Power | External 9 V AC adaptor[2] |
| Storage | 720 sectors of 128 bytes, 92,160 bytes per side[1] |
| Media | Single-sided 5.25-inch soft-sectored diskettes, 40 tracks at 48 TPI[2] |
The Atari 810 is a single-sided 5.25-inch floppy disk drive for the Atari 8-bit computers. Atari previewed it with the Atari 400 and Atari 800 at the Winter Consumer Electronics Show in January 1979 and began shipping it, with the 810 Master Diskette, in November or December 1979.[1] It records in single density (FM) on 40 tracks and connects to the computer through the serial I/O (SIO) bus, directly or through an Atari 850 or Atari 820. It has two I/O connectors, so up to four drives can be daisy-chained.[2] The 810 went through several board and mechanism changes during its life, and the Atari 1050 replaced it in 1983.[1]
Atari's Atari 810 Disk Drive Field Service Manual, FS015854 Rev. 1 of July 1980, describes the original two-board drive with the MPI mechanism.[2]
History
[edit | edit source]The first 810s used a Micro Peripherals, Inc. (MPI) mechanism, a side board and a rear board, and revision B of the drive firmware.[1] Atari then changed the design in four steps:[1]
| Date | Change |
|---|---|
| 1 September 1981 | External Data Separator Board fitted in the floppy controller socket of the side board ("DS" sticker); stepper motor circuit moved to a regulated 12 V |
| November 1981 | Revision C ROM ("C" sticker), with a new sector layout for the format command |
| February 1982 | "810 Analog" (810M Analog): a Power Supply Board in place of the rear board, with a tachometer frequency-to-voltage converter for the spindle speed, and an Analog Board on top of the mechanism, joined by a 10-pin ribbon cable |
| November 1982 | Tandon mechanism in place of the MPI mechanism ("810T Analog"), with a lift-up front latch and no eject mechanism |
The data separator board improved the drive's ability to tell data pulses from clock pulses, and Atari offered it as an upgrade for earlier drives, whose side boards needed modification to accept it.[1] The three Analog parts were also sold together as the CB101128 "Grass Valley Analog Board Set" for older drives.[1][3] Drives with the Tandon mechanism came with a 1982 product update sheet explaining that the new front panel has no eject button; the user lifts the tab to insert or remove a diskette.[4]
Third-party upgrades for the drive included the Happy 810 Enhancement (a one-track RAM buffer and "Warp Speed" reading), Spartan Software's Chip, which reads and writes non-standard disk formats, and the Neanderthal Computer Things 810 Turbo, which added double density.[1]
Specifications
[edit | edit source]| Item | Value |
|---|---|
| Recording | Single density (FM), single sided[2] |
| Tracks | 40 at 48 TPI[2] |
| Sectors | 18 per track of 128 bytes; 720 per side, 92,160 bytes[1] |
| Free sectors after formatting with DOS | 709[2] |
| Average data transfer rate | 6,000 bit/s[2] |
| Maximum data access time | 236 ms[2] |
| Track-to-track access | 5 ms[1] |
| Head settling | 15 ms[1] |
| Rotational speed | 290 rpm ±1 % (Atari, 1980); 288 rpm ±1 % (FAQ)[2][1] |
| Power consumption | 20 W (original); 21 W (data separator); 30 W (Analog)[1] |
The two speed figures conflict. Atari's 1980 manual gives 290 rpm in its theory of operation, while the FAQ list and Page 6 magazine give 288 rpm.[2][1][5] Page 6 notes that the stroboscope rings on the 810 flywheel were made for 300 rpm and so cannot be used to set the speed.[5]
Hardware
[edit | edit source]The original drive has two boards on a common baseplate. The side board carries the digital section and the rear board carries the power supply, the read and write amplifiers and the motor control.[2][6] Sams calls them the side (CPU) board and the rear (analog) board.[6]
| Position | Board | Device | Atari part number |
|---|---|---|---|
| A101 | Side | 6507 processor | C010745 |
| A102 | Side | Custom ROM (firmware) | C011299 |
| A103 | Side | 6810 RAM | C014328 |
| A104 | Side | 6532 RAM-I/O-timer | C010750 |
| A105 | Side | FD1771 floppy disk controller | C014329 |
| A106 | Side | Transistor array | C010174 |
| A107, A110, A111 | Rear | Transistor arrays (LM3086 in the Sams sample) | C010174 |
| A108 | Rear (on the baseplate) | Voltage regulator (7805 in the Sams sample) | C014348 |
| A109 | Rear | LM311 | C014332 |
The clock circuit produces a crystal-controlled 1 MHz signal for the floppy controller section and 500 kHz for the 6507.[2] The 6532 buffers the SIO lines, the stepper motor phases and the drive motor control, and reads the drive code switches.[2]
Power supply
[edit | edit source]The drive takes 9 V AC from an external step-down transformer through the PWR jack. The front power switch feeds a full-wave bridge rectifier, and the supply produces an unregulated 9-10 V DC for the drive motor, a regulated +5 V, a regulated +12 V from a voltage doubler, and a zener-regulated -5 V from a second doubler. The power LED is lit from the -5 V section.[2] The Sams schematic shows a 7805 (A108) for the +5 V rail, a TIP32A pass transistor (Q113) with MPSA06 error amplifiers (Q114, Q115) for +12 V, and a 1N5231 zener (CR107) in series with the power LED for -5 V.[6] A108 and Q113 bolt to the common baseplate, which acts as their heatsink; Q113 sits on an insulating plate with heat transfer compound.[2]
The early drives shipped with Atari's 9 V AC adaptor rated 15.3 VA (C014319, sold as CA014748). Drives with the data separator shipped with 31 VA adaptors, and the FAQ lists the 31 VA C017945 as suitable for the 810.[1]
Mechanism
[edit | edit source]The drive motor is a DC motor with an internal tachometer, and it turns the spindle through a pulley, a belt and a flywheel. A clutching cone centres and clamps the diskette when the door is latched. The stepper is a four-phase motor of 3.6 degrees per step, connected to the head carriage by a steel band.[2] The write protect sensor on the MPI mechanism is an LED and phototransistor; the Tandon mechanism uses a microswitch.[2][1]
| Item | MPI (pre-Analog and 810M Analog) | Tandon (810T Analog) |
|---|---|---|
| Front bezel | Door release button; diskette eject mechanism | Front latch; no eject mechanism |
| Upper arm | Pressure spring assembly | No pressure spring; adjusted by two nuts on the carriage |
| Stepper adjustment | Loosen setscrew, move the stepper band pulley | Cam screw at the rear of the mechanism |
| Track 00 stop | Set for 0.010 inch clearance | Set by watching the waveform amplitude |
| Write protect | Phototransistor | Microswitch |
Drive number
[edit | edit source]Two small switches behind a round window on the back select drive 1 to 4. With the black and white switches both to the left the drive is drive 1; black right and white left is drive 2; both right is drive 3; black left and white right is drive 4.[1] Set the switches with the power off, and keep one drive in the chain set to drive 1.[7][4]
Known faults
[edit | edit source]- The spindle speed drifts. On drives with the original rear board it is set with R142, a 500 kΩ trimmer on that board. Page 6 describes later drives with an extra board above the mechanism, where the speed control is R104.[2][5]
- Best Electronics, which sells 810 parts, reports that early drives without the data separator have read and write problems and that the single rear power board has speed problems, and fixes both with the data separator and the Analog board set.[3]
- A drive that is dead, or lights its LEDs without any mechanical movement, usually has a faulty rear power board, according to Best Electronics. Boot errors or a failure to format point to the mechanism, sometimes together with the side board.[3]
- The white pivot pins of the Tandon lift door break.[3]
- The drive belt comes off the flywheel or pulley, or stretches, and the diskette does not turn or turns at the wrong speed.[2]
- The plastic case is brittle and cracks easily in transit, and some cases have yellowed.[8]
Diagnosis is covered in the Atari 810 Drive Troubleshooting guide, cleaning and adjustments in the Atari 810 Maintenance Guide, and the electrolytic capacitors in the Atari 810 Capacitor Replacement Guide.
Documentation
[edit | edit source]- Atari 810 Documentation: the field service manual, the Sams Computerfacts, the owner's guide and the operator's manual, with contents and notes.
- Atari 810 Disk Drive Field Service Manual (FS015854 Rev. 1, July 1980)
- Sams Computerfacts CD9, Atari Model 810 (1986)
- The Atari 810 Disk Drive Owner's Guide (C060056 Rev. 1)
- Disk Drive Operators Manual (C014760, 1979)
Atari's later manual, FD100003 (Rev. 02 of July 1982 and Rev. 03 of May 1983), covers the Analog boards and the Tandon mechanism.[1][3]
Gallery
[edit | edit source]-
Rear panel: I/O connectors, power jack and drive code switch window -
Rear board CA014161 Rev. B silkscreen (FS015854 appendix) -
Speed adjustment guide and the location of R142 (FS015854 p. 7-10)
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Related pages
[edit | edit source]- Atari 810 Maintenance Guide
- Atari 810 Drive Troubleshooting
- Atari 810 Capacitor Replacement Guide
- Atari 810 Documentation
- Atari 1050
- Floppy Drive Repair
References
[edit | edit source]- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 Michael D. Current (ed.), Atari 8-Bit Computers: Frequently Asked Questions, comp.sys.atari.8bit FAQ, last modified 2 August 2026: section 3.2.1 (the Atari 810 disk drive, its revisions and upgrades), section 6.2 (power requirements) and section 11.1 (history, 1979 to 1983). 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 2.12 2.13 2.14 2.15 2.16 2.17 2.18 2.19 2.20 2.21 Atari, Inc., Atari 810 Disk Drive Field Service Manual (FS015854, Rev. 1, July 1980): specifications p. 1-3; theory of operation pp. 2-3 to 2-25 (drive motor p. 2-18, drive select p. 2-19, power supply p. 2-20, formatting pp. 2-23 to 2-25); troubleshooting guide pp. 5-3 to 5-7; disassembly pp. 6-3 to 6-25; adjustments pp. 7-3 to 7-14; parts lists pp. 8-3 to 8-10; rear board silkscreen, appendix E; error codes p. 9-9. Hosted here as File:Atari 810 Disk Drive Field Service Manual FS015854 Rev 1.pdf.
- ↑ 3.0 3.1 3.2 3.3 3.4 Best Electronics, "8-Bit Drives" catalogue page: Atari 810 Tech Tip and parts listings (CB101128 Analog board set, CA014834 side board, FD100003 field service manual). best-electronics-ca.com. Atari parts vendor's service notes.
- ↑ 4.0 4.1 Atari, Inc., The Atari 810 Disk Drive Owner's Guide (C060056 Rev. 1, 1981), with caution sheet C015554 Rev. A and product update sheet C061104 Rev. A (1982). Hosted here as File:Atari 810 Disk Drive Owner's Guide C060056.pdf.
- ↑ 5.0 5.1 5.2 Garry Francis, "Adjust It!", Page 6 no. 25 (January/February 1987), p. 54. page6.org. Magazine article.
- ↑ 6.0 6.1 6.2 Howard W. Sams & Co., Computerfacts CD9, Atari Model 810 (June 1986): schematic with voltages and waveforms pp. 2-3; parts list pp. 9-11; troubleshooting p. 12; disassembly p. 13. Hosted here as File:Sams Computerfacts CD9 Atari 810 Disk Drive.pdf.
- ↑ Atari, Inc., Disk Drive Operators Manual (C014760, 1979): setting up, front and back panel, technical specifications, troubleshooting. Hosted here as File:Atari 810 Disk Drive Operator's Manual C014760.pdf.
- ↑ Jason H. Moore, "Clean an 810/1050 Disk Drive Head (15-30 min)", Atari Projects, 4 August 2018. atariprojects.org. Community write-up.