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Coleco Telstar General Maintenance

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Coleco Telstar (3)
The Telstar's centre panel: the three-position game switch, ON/OFF, RESET and the BEGINNER/INTERMEDIATE/PRO switch. A 2026 review found the game switch on one 6040 stuck.

Routine care for the first Coleco Telstar (model 6040), Coleco's three-game Pong console of 1976 built on General Instrument's AY-3-8500.[1] The parts that need attention are the battery compartment, the slide switches, the paddle controls, the game cable and the adapter socket. No service manual or owner's guide for the 6040 has been found. Faults are dealt with on Coleco Telstar Troubleshooting Guide.

Before you start

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  • Remove the cells and unplug any adapter.
  • Note the positions of the game switch and the BEGINNER/INTERMEDIATE/PRO switch so that you can check them afterwards.[2]
  • Have an analogue television, or a box with an analogue tuner, for VHF channel 3.[3]

Case

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The Telstar has a cream plastic case with woodgrain panels, the paddle knobs on either side and the controls in a raised centre panel.[4] Coleco shipped Telstars partly assembled, with the knobs and decorative stickers for the owner to fit, so knobs and labels can differ from one console to another.[1]

No photograph of the 6040's underside or board has been published. Pong-Story says the Coleco Telstar Ranger uses the same case in black, and the photographed Ranger's base is held by six screws around its edge, with the cells under a door held by two more.[5][6] Expect a similar arrangement on the 6040, but check yours before prising anything; see Coleco Telstar Ranger General Maintenance#Opening the base for that console.

Battery compartment

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The Telstar takes six C cells.[3]

  1. Remove the cells and look at each contact and spring for white or green deposits.
  2. Clean light deposits with isopropyl alcohol and a fibreglass pen; for heavy corrosion follow Battery Explosion, Capacitor or Corrosion Damage.
  3. Check each spring still presses firmly. With six cells in series, one weak contact drops the whole supply.
  4. Store the Telstar without cells.

Adapter and socket

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Coleco's adapter for the Telstar range was the TELSTAR AC Adaptor Model 6041. Two photographed examples carry different ratings: 9 V DC 100 mA on one shown with a boxed 6040, and 9 V DC 200 mA (117 V 60 Hz, 5 W input) on another.[7][8] Neither label gives the plug polarity.

  • Check an old 6041's case and lead for cracks before plugging it into the mains, and measure its output off load.
  • Before using any other 9 V supply, find the socket's polarity, either from a known-good 6041 or by tracing the socket's contacts to the battery terminals with the case open.
  • Clean the socket with contact cleaner on a pipe cleaner if the game only runs when the plug is moved.

Switches and RESET

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The panel has a three-position game switch (TENNIS, HOCKEY, HANDBALL), an ON/OFF slide switch, a RESET button and a three-position BEGINNER/INTERMEDIATE/PRO switch.[2] On the 6040 reviewed by Lon.TV in 2026 the game switch was stuck and the difficulty switch did not shrink the paddles at PRO.[3] Pong-Story notes that the game switches on GI-chip consoles could fail after many selections.[9]

  1. With the power off, spray a little contact cleaner (DeoxIT D5 or similar) into each slide switch.
  2. Work it through all its positions many times. If it is stuck, do not force it; free it with cleaner first, or with the case open.
  3. Press RESET repeatedly.
  4. Check each closed contact with a meter. The AY-3-8500 needs 1 kΩ or less to ground for a selected game or setting.[10]

Paddle controls

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The two paddle knobs turn the controls that move the paddles up and down.[11][10] If a paddle jitters or jumps, pull the knob, work contact cleaner into the control and turn it end to end many times. The value Coleco used has not been published; measure the old part if one needs replacing.

Game cable, ferrite ring and switch box

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The Telstar reaches the television through its game cable and Coleco's antenna switch box, which has GAME and TV positions and spade terminals for the set's twin-lead aerial input.[3][7] Ralph Baer recalls that the first Telstars passed the FCC's radio-interference test only after a ferrite toroid was put on the coaxial cable with two tight turns just inside the cabinet.[12]

  • Inspect the cable where it leaves the case, and clean its plug and the switch box contacts.
  • If you open the case and find a ferrite ring on the cable, keep it and keep the turns through it when you replace or shorten the cable.
  • On a modern set, use a television or box with an analogue tuner on channel 3.

Storage

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  • No cells inside.
  • Switch box and cable stored with the console, coiled loosely.
  • Away from heat and damp.

Preventive maintenance checklist

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  1. Remove the cells and inspect the contacts.
  2. Clean the three slide switches and RESET.
  3. Clean the two paddle controls.
  4. Inspect the game cable and switch box.
  5. Check any adapter's output and lead before use.
  6. Test tennis, hockey and handball at BEGINNER, INTERMEDIATE and PRO, and confirm that the paddles shrink at PRO.
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References

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  1. ↑ 1.0 1.1 David Winter, Pong-Story, "Coleco Telstar systems" (retrieved 2026-10-18): Telstar, released in 1976, played three games with three difficulty levels and was the first system to use GI's AY-3-8500; over a million units sold; variants sold as the Telstar Deluxe in Canada and by Montgomery Ward as "Telstar Video World of Sports"; Coleco's systems were sold partially assembled, with the knobs and decorative stickers fitted by the user.
  2. ↑ 2.0 2.1 Photograph by Sintegrity, File:Coleco Telstar (3).jpg (CC BY-SA 4.0, from Wikimedia Commons): centre panel with TENNIS/HOCKEY/HANDBALL slide switch, ON/OFF slide switch, RESET push button and BEGINNER/INTERMEDIATE/PRO slide switch.
  3. ↑ 3.0 3.1 3.2 3.3 Lon.TV, "This Was the Best Selling Game Console of 1976", blog post, 4 February 2026 (retrieved 2026-10-19): a Telstar model 6040 bought for a historical-society display; launched at $50; AY-3-8500 with the game logic in the chip; sound from a built-in speaker; RF output for VHF channel 3 through a switch box; designed to run on six C cells, with a power connector for an optional supply; on his unit the game selector switch was stuck and the difficulty slider did not resize the paddles at the "pro" setting.
  4. ↑ Photograph by Jzh2074, File:Coleco Telstar (1976) 2.jpg (CC BY-SA 4.0, from Wikimedia Commons): cream case, woodgrain panels, speaker grille at the upper left.
  5. ↑ David Winter, Pong-Story, "Coleco Telstar Ranger" (retrieved 2026-10-18): the Ranger uses the same case as the Telstar, in black.
  6. ↑ Photograph by Dan McMahill, File:1977 Coleco Telstar Ranger Bottom.jpg (CC BY-SA 4.0, from Wikimedia Commons): base of a Telstar Ranger with six screws around its edge and a battery door held by two screws.
  7. ↑ 7.0 7.1 Photograph by Chris Yarzab, File:Telstar (51908701248).jpg (CC BY 2.0, from Wikimedia Commons), read at full size: a Telstar model 6040 with its box, the antenna switch box (GAME/TV, "Made in U.S.A.") and a TELSTAR AC Adaptor Model 6041 labelled "OUTPUT: 9V DC 100mA".
  8. ↑ Photograph by Evan-Amos, File:Coleco-Telstar-AC-Adaptor.jpg (public domain, from Wikimedia Commons): label "TELSTAR AC ADAPTOR MODEL 6041 ... INPUT: 117V 60Hz 5W OUTPUT: 9 V DC 200mA".
  9. ↑ David Winter, Pong-Story, "PONG in a Chip" (retrieved 2026-10-18): two versions of the AY-3-8500 exist, the early one with a dashed central line about twice as large and solid horizontal boundaries; the undocumented seventh game, Handicap, is played when none of the six games is selected; game selection switches "(rotary or linear) which could fail after many game selections".
  10. ↑ 10.0 10.1 General Instrument, GIMINI TV Game Circuits, January 1978, pp. 4-6, File:General Instrument GIMINI TV Game Circuits (January 1978).pdf: AY-3-8500 pin functions (VSS pin 2, sound pin 3, VCC pin 4, ball speed pin 7 open for low speed and grounded for high, bat size pin 13 open for large bats and grounded for small, sync pin 16, clock pin 17 at 2.012160 MHz ±1%, game inputs pins 18 to 23 grounded to select); standard conditions VCC +6 to +7 V, +12 V maximum; supply current 40 mA typical, 60 mA maximum at +7 V; control inputs need 1 kΩ or less to VSS; vertical bat movement; scores 0 to 15.
  11. ↑ Arcade-History, "Telstar [Model 6040"] (retrieved 2026-10-19): model 6040, 1976; three Pong games (tennis, hockey, handball); two knobs built into the console; RESET button; ON/OFF and Beginner/Intermediate/Pro switches; black and white; built-in beeper; on-screen score.
  12. ↑ David Winter, Pong-Story, "Coleco Telstar" (retrieved 2026-10-18): first model, 1976; Ralph Baer's account that Coleco's first Telstar failed the FCC radio-frequency interference tests until he slipped a ferrite toroid over the shielded coaxial cable coming out of the unit, with two tight loops through the ring just inside the cabinet, after which the unit passed; two versions of the console, one with linear speaker holes at the upper left that shows a solid centre line in tennis and one with small round holes that shows a dashed line, believed to reflect a first run and a revision of the AY-3-8500.


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