Atari Stunt Cycle
 | |
| Atari Stunt Cycle, model SC-450, with its handlebar grips and game buttons | |
| Specifications | |
|---|---|
| Manufacturer | Atari, Inc. |
| Type | Dedicated home video game console |
| Released | 1977[1][2] |
| CPU | None; General Instrument AY-3-8760 game chip[3][1] |
| Memory | None |
| Storage | — |
| Display | RF output to a television on channel 3[4] |
| Sound | Speaker in the console, with a volume switch[4] |
| Power | AC power supply C010472, 9 V DC at 500 mA[4] |
| OS / Firmware | — |
| Codename | Stunt Debbie[5] |
| Model no. | SC-450[4] |
The Atari Stunt Cycle (model SC-450) is a dedicated home video game console that Atari released in 1977, based on its 1976 arcade game of the same name. The player rides a motorcycle across three levels of track and jumps a growing row of buses, steering speed with a twist-grip throttle on the right-hand handlebar. The console plays four games: Stunt Cycle, Drag Race, Motocross and Enduro.[1][4] Sears sold a version with 16 Pong games added as Motocross (model 99729).[2]
History
[edit | edit source]Atari's arcade Stunt Cycle of 1976 has a cabinet shaped like a motorcycle's handlebars, with the right grip twisted to accelerate.[1] The home console followed in 1977 under the codename "Stunt Debbie".[5][1] Atari's own version plays only the four motorcycle games. The Sears Tele-Games version, which Wikipedia calls the Motocross Sports Center IV, adds detachable Pong controllers and the 16 Pong games of Ultra Pong Doubles.[1][2] Pong-Story notes that Atari's version has no Pong chip in it.[2]
Games and controls
[edit | edit source]The controls along the front of the console are, from left to right, the Power, Difficulty and Volume switches and the four game buttons; the right-hand grip is the throttle. Pressing a game button puts that game's track on the screen.[4]
| Game | Play | PRO difficulty |
|---|---|---|
| Stunt Cycle | Ride the first two tracks, then jump the buses on the third. Start with 8 buses; each clean jump adds one. The game ends after the eighth crash. | Throttle very sensitive; game ends after the fourth crash |
| Drag Race | Race the clock across all three tracks, changing into second and third gear by twisting the throttle quickly towards you and forward again. | Throttle very sensitive; over-throttling flips the cycle |
| Motocross | Race the clock over one barrier per track, lifting the front wheel with a burst of throttle. | Two barriers per track |
| Enduro | Jump the barriers on the first two tracks and the buses on the third, starting with 8 buses. The game ends after the eighth crash. | Two barriers per track; game ends after the fourth crash |
On screen the left number counts crashes and the right number shows how many buses are in the row.[4] The box advertises jumps of up to 32 buses.[6]
The white areas of the playfield brighten once the throttle is turned and dim again within two minutes if the console is left switched on after a game. Atari's manual describes this as normal; the console is designed not to burn the playfield into the screen, and Atari still advises turning down the television's contrast and switching the game off when not in use.[4]
Hardware
[edit | edit source].jpg)
The games come from General Instrument's AY-3-8760 motorcycle game chip, which Pong-Story records in both Atari's Stunt Cycle and Sears's Motocross; GI also made a PAL version, the AY-3-8765.[3][1] arcade-history.com describes the console as using a custom microcontroller, which disagrees with the GI chip named by Pong-Story and Wikipedia.[7]
Ctrl-Alt-Rees, restoring an SC-450 in 2023, found that it uses the same RF modulator as the Atari Video Pinball, developed alongside it, and that its board was coated in old flux. He found one electrolytic capacitor on the board, a crystal oscillator, a trimmer and a 5 V regulator.[6]
Power
[edit | edit source]The console runs only from its AC power supply, Atari part C010472, which plugs into a jack on the back and gives 9 V DC at 500 mA. Atari's manual warns that any other supply can damage the circuits.[4] The Atari 8-bit FAQ lists C010472 as a 9 V DC, 500 mA, centre-positive unit that also suits the Atari 2600.[8] Atari's battery Pong consoles take the same style of plug but need about 6 V, so label the adaptors when several consoles share a bench.[6]
Troubleshooting
[edit | edit source]| Symptom | Cause and remedy |
|---|---|
| No playfield, or a whitish-grey screen | Switch box set to TV (set it to GAME); game cable not plugged into the switch box; twin-lead not attached to the TV; power switch off; TV off or on the wrong channel. Switch back to normal TV briefly to check the set itself. |
| No regular TV programmes | Switch box set to GAME (set it to TV); twin-lead not attached to the TV; antenna wire not on the 300 Ω screws of the switch box. |
| Clear playfield, but bars or lines move across it | A strong station on channel 3 or on cable: remove the antenna wire or cable from the switch box while playing. |
| Playfield fuzzy, like a weak station | Poor connections at the TV's antenna terminals or the switch box. |
| Playfield unsharp, unsteady or without colour | Fine-tune the TV and set its colour and tint. |
| Worked before, now unsharp or unstable | The TV's fine tuning has been moved: re-tune. |
| Display distorted or scrambled | Adjust the TV's horizontal and vertical hold, then the fine tuning. |
| Display not centred | The TV's horizontal hold gives a little centring; some sets have a horizontal centring control at the back. |
Ctrl-Alt-Rees's SC-450 had a rolling picture that he took for a timing fault. Adjusting the trimmer, replacing the single electrolytic capacitor and replacing the 5 V regulator did not cure it, and he suspected the crystal oscillator.[6]
Composite video
[edit | edit source]Ctrl-Alt-Rees converted his SC-450 to composite video by removing the RF modulator and wiring the video signal into one channel of a THS7314 video amplifier board, with a 75 Ω resistor on the output. He wired the audio in parallel with the internal speaker. The Video Pinball takes the same modification.[6]
Replacement parts
[edit | edit source]| Part | Number |
|---|---|
| TV/game switch box | CA010325 |
| AC power supply | C010472 |
| Rubber foot | 88-1004 |
| Owner's manual | C010931 |
Documentation
[edit | edit source]- Atari Stunt Cycle Documentation: the owner's manual.
- Stunt Cycle owner's manual (C010931, 1977)
Related pages
[edit | edit source]References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Wikipedia, "Stunt Cycle", revision 1349387671: the 1976 arcade game, its cabinet, and the two 1977 home versions with their chips. en.wikipedia.org.
- ↑ 2.0 2.1 2.2 2.3 David Winter, Pong-Story, "Atari home PONG systems": Stunt Cycle and Motocross, model numbers, years, and the absence of a Pong chip in Atari's version. pong-story.com.
- ↑ 3.0 3.1 David Winter, Pong-Story, "General Instrument" chips: the AY-3-8760 "Cycle" chip used by Atari and Sears, and the AY-3-8765 PAL version. pong-story.com.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 Atari, Inc., Stunt Cycle owner's manual, model SC-450, C010931, 1977: unpacking (p. 2); switch box (pp. 3-4); AC power supply and console controls (p. 5); starting play, the Stunt Cycle game and the note on playfield brightness (p. 6); Drag Race and Motocross (p. 7); Enduro and care (p. 8); phosphor note and troubleshooting checklist (pp. 9-10); replacement parts (p. 10). Hosted as File:Atari Stunt Cycle Owner's Manual C010931.pdf.
- ↑ 5.0 5.1 Curt Vendel, Atari Museum, "The Atari Stunt Cycle Dedicated Home Console": codename and model number. atarimuseum.ctrl-alt-rees.com.
- ↑ 6.0 6.1 6.2 6.3 6.4 Ctrl-Alt-Rees, "A Curious Atari Video Game Machine Restoration", 28 December 2023: the Stunt Cycle box, its RF modulator, board, composite mod and rolling-picture fault, and the 6 V and 9 V adaptors. ctrl-alt-rees.com. Restoration report.
- ↑ arcade-history.com, "Stunt Cycle [Model C450]": games and the description of the console. arcade-history.com. Community database.
- ↑ Michael D. Current (ed.), Atari 8-Bit Computers: Frequently Asked Questions, last modified 2 August 2026, section 6.2: power supply C010472, 9 V DC 500 mA, centre positive, and the equipment it serves. mcurrent.name.