Coleco Telstar Classic Troubleshooting Guide
Fault-finding for the Coleco Telstar Classic (model 6045), the 1976 wooden-cased Telstar that runs only from a mains adapter.[1][2] Coleco printed a trouble-shooting chart in the Classic's guide, reproduced below; it has no battery entries because the Classic has no cells.[3] No schematic or board photograph of the Classic has been published, so the bench checks use General Instrument's data for the AY-3-8500. Cleaning and the adapter are covered in Coleco Telstar Classic General Maintenance.
What should happen at power-on
[edit | edit source]With the adapter plugged in, the switch box at GAME and an analogue television tuned to channel 3:[4]
- Switching ON and pressing RESET starts a game with the scores at the top of the screen.[5]
- The game selector chooses tennis, hockey or handball.[4]
- BEGINNER gives the slowest ball and largest paddle, INTERMEDIATE a smaller paddle and PRO the fastest ball.[5]
- After 15 points the ball passes through the paddles without scoring until RESET.[5]
Expected measurements
[edit | edit source]| Point | Expected | Source |
|---|---|---|
| Mains supply to the original adapter | 115 V 60 Hz only | [2] |
| Adapter output | Not published; measure a known-good adapter | [2] |
| AY-3-8500 pin 4 to pin 2 | +6 to +7 V; 12 V absolute maximum | [6] |
| AY-3-8500 supply current | 40 mA typical, 60 mA maximum at +7 V | [6] |
| AY-3-8500 pin 17 | 2.012160 MHz ±1% | [6] |
| Closed switch to ground | 1 kΩ or less | [6] |
Coleco's trouble-shooting chart
[edit | edit source]Coleco tells the owner to check that the television and switch box connections are secure before anything else.[3]
| Symptom | Coleco's remedy | Bench follow-up |
|---|---|---|
| No game; faint TV image or herringbone pattern | Set the switch box to GAME and plug the cable in properly; attach the antenna lead properly; plug the AC adapter into the wall; switch ON; tune to channel 3; adjust fine tune[3] | Measure the adapter output at the plug, then pin 4 and pin 17 of the AY-3-8500[6] |
| Picture rolls or flutters; bottom line off screen; buzzing from the TV | Adjust vertical hold; turn the TV volume down[3] | If no setting locks the picture, look at the sync and video mixing; the chip's sync output is pin 16[6] |
| Stripes; lots of dots | Adjust horizontal hold; reduce colour intensity on a colour set; adjust fine tune and contrast[3] | As above |
| Vertical or horizontal line moving across the screen | Press RESET; adjust contrast[3] | None if RESET clears it |
| Ball erratic; score not 0-0 | Switch off and let the game cool; do not place it on top of the TV; press RESET rapidly[3][5] | A sagging supply is the likely cause: measure the adapter under load and pin 4 of the chip |
Further faults
[edit | edit source]| Symptom | Likely cause | Action |
|---|---|---|
| Dead, adapter plugged in | Adapter failed; broken lead; dirty receptacle | Measure the adapter off load. Clean the receptacle at the right of the name strip.[7] |
| A setting does nothing, or only works when the switch is wiggled | Dirty or worn slide switch | Clean it and measure it closed: 1 kΩ or less to ground.[6][8] |
| Wrong game, or a soccer-style game with a third paddle | Game selector between positions | With no game input grounded the chip plays its hidden game, Handicap. Clean the selector.[8] |
| Paddle jumps or will not reach the edge | Dirty paddle control | Clean it or measure it. |
| No sound | Speaker or wiring | The chip's sound output is pin 3; the speaker is under the grille at the left.[6][7] |
Things that are not faults
[edit | edit source]- Play stops at 15 points until RESET.[5]
- The score may need several presses of RESET to return to 0-0.[5]
- There is no battery compartment.[2]
- The paddles move only up and down.[6]
What is realistically repairable
[edit | edit source]| Part | Repairable? | Notes |
|---|---|---|
| Adapter | Replaceable | Find the original's output before choosing a substitute, and stay within the chip's limits.[6] |
| Wooden case | Yes | Ordinary woodwork; keep it dry. |
| Slide switches and RESET | Usually | Clean first; a replacement must fit the plate. |
| Paddle controls | Yes | Measure the old part. |
| Electrolytic capacitors | Yes | See Coleco Telstar Classic Capacitor Replacement Guide. |
| AY-3-8500 | Only by transplant | Rule out supply, clock and switches first. |
Related pages
[edit | edit source]- Coleco Telstar Classic
- Coleco Telstar Classic General Maintenance
- Coleco Telstar Classic Capacitor Replacement Guide
- Coleco Telstar Troubleshooting Guide, for the plastic, battery-powered version
- Capacitor Failure Symptoms
References
[edit | edit source]- ↑ David Winter, Pong-Story, "Coleco Telstar Classic" (retrieved 2026-10-18): model 6045, released in 1976; the same as the first Telstar but in a deluxe wooden case, and more expensive.
- ↑ 2.0 2.1 2.2 2.3 Coleco Industries, Telstar Classic: Installation Instructions and Game Rules, Model No. 6045, Guide No. 57337D, 1976, p. 1, File:Coleco Telstar Classic Installation Instructions (Guide 57337D).pdf: three video games (tennis, hockey, handball); automatic digital display scoring 0-15; three-position speed and paddle size; hit, score and rebound sounds; "AC Operated 115V-60Hz Only"; four rubber bumpers pressed into the corner holes of the bottom housing.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Coleco, Guide No. 57337D, p. 4, "Telstar - Trouble Shooting Guide": "Do not open. This device does not contain any serviceable parts."; symptoms and remedies (no game or faint picture: switch box at Game, antenna lead, AC adapter plugged in, ON, channel 3, fine tune; picture rolls, bottom line off screen or buzzing: vertical hold, TV volume; stripes or dots: horizontal hold, colour intensity, fine tune and contrast; line moving across screen: reset, contrast; ball erratic or score not 0-0: shut off and allow to cool, not on top of the TV, depress reset rapidly); 90-day warranty; service at $17.50 within 2 years of purchase via factory regional service stations in Amsterdam, New York, and Tustin, California.
- ↑ 4.0 4.1 Coleco, Guide No. 57337D, p. 2: "Switch box and adapter are found in the base of your Telstar unit. Plug in adapter to wall outlet and insert jack into adapter receptacle on your game."; switch box connections and a 75 to 300 ohm balun for cable TV; channel 3; panel diagram (speaker, game selector TENNIS/HOCKEY/HANDBALL, AC adapter receptacle, left and right paddle controls, ON-OFF switch, Variable Action Control BEGINNER/INTERMEDIATE/PRO, reset button, game cable).
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Coleco, Guide No. 57337D, p. 3: to play the game; reset starts a new game and removes lines moving across the screen; after 15 points the ball moves through the paddle without scoring; "If score does not immediately return to 0-0, depress Reset button repeatedly until it does."; shut Telstar off when not in use and move the switch box selector to TV; rules for tennis, hockey and handball.
- ↑ 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 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; reset input pin 25 momentarily grounded to reset the score counters and start a new game); 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.
- ↑ 7.0 7.1 Photograph by Philmortonfan, File:1976 Coleco Telstar Classic.jpg (CC BY-SA 4.0, from Wikimedia Commons), read at full size: wooden case; name strip with a speaker grille at the left and a round socket at the right; centre plate with TENNIS/HOCKEY/HANDBALL, ON/OFF, RESET, CLASSIC and BEGINNER/INTERMEDIATE/PRO; two screw heads in the lower edge of the wooden front.
- ↑ 8.0 8.1 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".
