Mattel Basketball Troubleshooting Guide
Fault-finding for Mattel Basketball (model 2437). Begin with the battery: Mattel's leaflet gives misbehaving player blips or scoreboard as the first sign of battery wear.[1] The circuit is a National Semiconductor MM5799 microcontroller die bonded to the board, with a 4001 and a 74154; the 74154 selects the display digits and LEDs and drives the speaker.[2] Read Mattel Basketball General Maintenance before opening the case.
Things that are not faults
[edit | edit source]- At switch-on the readout shows the minutes left in the first quarter. Depending on the version of the program this is 12 or 15.[1][2]
- Moving the switch between 1 and 2 after play has started ends the game.[1]
- At the end of the fourth quarter a long buzzer sounds and the keys stop working. Switch to OFF and back on to start a new game.[1]
- A move into a square held by a defender, or out of bounds, is cancelled.[1]
- After the whistle the readout flashes the visitors' score, the home score and the minutes left; pressing the arrow with the dot shows them again.[1]
- A shot from outside a clear lane bounces off the backboard and becomes a loose ball.[1]
Symptoms
[edit | edit source]| Symptom | Probable cause | Action |
|---|---|---|
| Nothing lights when switched on | Flat battery; corroded or broken snap or lead; dirty or stiff switch | Fit a fresh battery. Measure the voltage at the board end of the battery leads with the switch on. Replace a corroded snap; clean or free the switch. One owner's game needed both a new clip and a freed switch.[3] |
| Blips or readout erratic, dim or flickering | Battery wearing out | Fit a fresh 9 V alkaline battery, as Mattel recommends.[1] National's data sheet gives the MM5799 an operating range of 7.9 V to 9.5 V between its supply pins.[4] |
| Dead after a battery was connected the wrong way round | Damaged MM5799 die | Reverse connection has burned bond wires and metal on one die.[5] The die cannot be replaced; a donor board is needed. |
| Dead or intermittent, battery and switch good | Broken connection on the board | Inspect joints and tracks under magnification and resolder; one dead game was cured this way.[6] |
| One arrow key does nothing | Dirty contact under that key | Clean the key contact. |
| Neither SHOOT key works | The line the two keys share | The program reads both SHOOT keys as one input, so check the wiring they have in common.[2] |
| One SHOOT key works, the other does not | Contact under the dead key | Clean that key's contact.[2] |
| Game will not run at 1 or at 2 | Dirty slide switch | Clean the switch with switch cleaner. |
| No sound, display normal | Speaker or its connections | The 74154 drives the speaker from two of its outputs; check the speaker and its joints.[2] |
| Several LEDs or a whole digit dark together | One of the 74154 select lines, or a shared segment line | The 74154 selects the digits and LEDs; a dead output puts out everything on that line. The bonded chips are not replaceable.[2] |
| Garbled display or nonsense play with a good battery | Damaged bond wires on the MM5799, or the die itself | The bond wires under the plastic cover break very easily; a damaged die means a donor board.[5] |
Checks with a meter
[edit | edit source]- Measure the battery off load and with the game running. National's data sheet gives the MM5799 a supply range of 7.9 V to 9.5 V and a typical current of 12 mA, 18 mA at most, before the LEDs and speaker are counted.[4]
- With the battery fitted and the switch on, measure at the board end of the battery leads. No voltage with a good battery means a broken snap or lead.
- Check the snap's polarity against the board before every new battery or snap goes in.[5]
- With the battery out, check the slide switch for continuity in each position.
- Do not probe on or under the plastic cover over the MM5799 die.[5]
No schematic of the Basketball board has been published, so the supply arrangement between the battery and the chip is not documented.
What is realistically repairable
[edit | edit source]| Part | Option |
|---|---|
| 9 V snap and leads | Standard part; replace[3] |
| 1-OFF-2 switch | Clean, or free a stiff switch with a little oil[3] |
| Broken joints and tracks | Resolder[6] |
| Case screws | Stripped triangular screws can be drilled out and replaced with Phillips screws[3] |
| MM5799, 4001, 74154 | Bonded directly to the board; not replaceable, donor board only[2][5] |
Related pages
[edit | edit source]- Mattel Basketball
- Mattel Basketball General Maintenance
- Mattel Basketball Capacitor Replacement Guide
- Mattel Soccer Troubleshooting Guide
- Capacitor Failure Symptoms
- Battery Explosion, Capacitor or Corrosion Damage
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Mattel, Inc., Mattel Electronics Basketball Game Instructions, code 2437-0920(A), 1978; hosted here as File:Mattel Electronics Basketball Instructions 2437-0920.pdf. PDF p. 3: the computer cancels a move into an occupied position or out of bounds; at switch-on the clock shows the minutes remaining in the first quarter (the drawing shows 12). PDF p. 4: scores flashed after the whistle, repeated with the arrow with the dot; "Don't switch between 1 and 2 after starting play or the game will end." PDF p. 5: a shot from other positions heads for the backboard and becomes a free ball. PDF p. 6: at the end of the fourth quarter a long buzzer sounds and the control keys cease to function; switch to OFF and back to start a new game. PDF p. 7: misbehaving blips or scoreboard are "the first sign of battery wear"; a 9 volt alkaline battery for longer life.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 MAME source, src/mame/handheld/hh_cops1.cpp at commit bdc96c8 (retrieved 2026-10-19): MM5799 die, 4001 and 74154 bonded to the PCB; 74154 outputs 2 and 6 drive the speaker and outputs 3-5 and 10-13 select the digits and LEDs; both SHOOT buttons on the one INB input; two versions of Basketball showing "12" or "15" at power-on.
- ↑ 3.0 3.1 3.2 3.3 Radio Boat Anchor, "1978 Mattel Electronic Basketball repair", YouTube, 23 January 2024, video description (read 2026-10-19): a new 9 V battery clip; a very stiff switch oiled; triangular anti-tamper screws, two stripped heads drilled out and replaced with Phillips screws.
- ↑ 4.0 4.1 National Semiconductor, MOS/LSI Databook (1977), MM5799 data sheet, "dc electrical characteristics"; copy at seanriddle.com/nationalcopsi.pdf, PDF p. 29 (retrieved 2026-10-19): operating voltage (VSS − VDD) 7.9 V minimum, 9.5 V maximum; operating supply current 12 mA typical, 18 mA maximum at 9.5 V, excluding outputs.
- ↑ 5.0 5.1 5.2 5.3 5.4 Sean Riddle, "National Semiconductor MM5799" (retrieved 2026-10-19): the die bonded directly to the PCB under a plastic cover; "it's very easy to break the exposed bond wires"; a Basketball that "had the battery connected backwards, which vaporized some bond wires and metal".
- ↑ 6.0 6.1 Rusty Shepherd, "1978 Mattel Electronics Basket Ball game. Broken. Restoration.", YouTube, 1 July 2020, video description (read 2026-10-19): not working when received; "a broken connection on the mother board. A little solder and we were all good."