Mattel Auto Race Troubleshooting Guide
Fault-finding for the Mattel Auto Race (model 9879). Start with the battery and its snap: Mattel's leaflet names a wearing battery as the first cause of a misbehaving display.[1] The circuit is a single Rockwell B6000 microcontroller driving the LEDs and a piezo speaker directly, with no separate display or sound chips.[2][3][4] Read Mattel Auto Race General Maintenance before opening the case.
Things that are not faults
[edit | edit source]- The game will not start unless the gear switch is in first gear.[1]
- RESET is the off position of the START/RESET switch.[1]
- The steering lever stays where it is left; it does not spring back to the centre lane.[2]
- After a collision the car is pushed back towards the start line, and after each lap it returns to the bottom of the track.[1]
- If four laps are not finished in 99 seconds the timer stays at 99 and a steady defeat tone sounds until the game is switched off.[5][1]
- The game's speed depends on the trimmer inside. A game that runs noticeably faster or slower than another may have had its trimmer moved.[6]
Symptoms
[edit | edit source]| Symptom | Probable cause | Action |
|---|---|---|
| Nothing lights at START | Flat battery; corroded or broken snap; broken battery wire; dirty START/RESET switch | Fit a fresh battery. Measure the voltage at the snap's wires on the board with the battery fitted. Replace a corroded or broken snap; a dead Auto Race repaired in 2024 came back to life with a new one.[7] |
| Car blips or timer digits erratic, dim or flickering | Battery wearing out | Fit a fresh battery first. Mattel's leaflet gives this as "the first sign of battery wear".[1] |
| Display lights but the race will not start | Gear switch not in first; dirty gear switch | Set the gear switch to 1 and start again.[1] If it still will not start, clean the gear switch. |
| Some gears or lanes do nothing | Dirty or worn slide switch | Clean the gear or steering switch; check its solder joints. |
| Game far too fast or too slow | Speed trimmer moved | Set the trimmer to about the middle of its travel and adjust from there.[6] |
| No sound, display normal | Piezo speaker or its wires | Check the speaker's connections; the chip drives it from a single output with no amplifier.[3] |
| One LED or one digit segment never lights | That LED, or its joint on the display board | Inspect the display board joints; compare with the matrix description below. |
| A whole group of LEDs dark together | A shared row or column line, or the pins joining the display board to the main board | Reflow the row of pins along the display board edge and inspect the tracks.[4][2] |
| Works only while the case is squeezed | Cracked joint or broken wire, for example at the battery leads | Inspect the snap wires and the joints round the switches.[7] |
| Display garbled after the battery, snap, switches and capacitor have been checked | B6000 fault | The B6000 is a custom Rockwell part with the game in its own ROM; a donor board is the only replacement.[8][3] |
Checks with a meter
[edit | edit source]- Measure the battery off load and then with the game running. A battery that falls away sharply under load is the first thing to replace.
- With the battery fitted and the switch at START, measure between the red and black battery leads where they join the main board. No voltage there with a good battery means the snap or a lead is broken.[7]
- Check each slide switch for continuity in each position with the battery removed.
- Look at the electrolytic capacitor for bulging or leakage; see Mattel Auto Race Capacitor Replacement Guide.
No data sheet for the B6000 has been published, so there is no published supply-voltage range for the chip; Rockwell designed it specially for Mattel from one of its calculator chips.[8][3][2]
How the display is driven
[edit | edit source]The B6000 multiplexes the display: Lesser describes adapting the calculator chip's eight digit drivers to handle both the playfield and the timer.[3] MAME's driver models it as a matrix of nine select lines by eight segment lines, with the 21 track LEDs and two seven-segment digits on it.[2] Because of this, a fault on one line puts out a whole group of LEDs at once, while a fault on one LED or its joint affects only that position.
What is realistically repairable
[edit | edit source]| Part | Option |
|---|---|
| 9 V snap and leads | Standard part; replace[7] |
| Slide switches | Clean; replace with a matching slide switch if worn |
| Speed trimmer | Clean or replace with a trimmer of the same value, read from the part[6] |
| Electrolytic capacitor | One 10 µF 25 V part; see Mattel Auto Race Capacitor Replacement Guide[4] |
| B6000 microcontroller | Custom; donor board only[8] |
Related pages
[edit | edit source]- Mattel Auto Race
- Mattel Auto Race General Maintenance
- Mattel Auto Race Capacitor Replacement 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 Mattel, Inc., Mattel Electronics Auto Race Game Instructions, code 9879-0920(B), 1976; hosted here as File:Mattel Electronics Auto Race Instructions 9879-0920.pdf. PDF p. 1: START, RESET and OFF. PDF p. 2: "Game will not start unless you start in first gear (set gear switch to #1)"; collisions may put the car back towards the starting line; the car returns to the start line after each lap; the sound of victory or of defeat. PDF p. 6: "If the blips of light representing cars or the Digital Timer appear to be malfunctioning, this is the first sign of battery wear. A fresh battery should solve the problem."
- ↑ 2.0 2.1 2.2 2.3 2.4 MAME source, src/mame/handheld/hh_rw5000.cpp at commit d912c4f (retrieved 2026-10-19): B6000 microcontroller; 2-digit 7-segment display and 21 other LEDs on a 9 × 8 display matrix; 1-bit sound; steering "does not auto-center on real device"; hardware and programming by Rockwell.
- ↑ 3.0 3.1 3.2 3.3 3.4 Scott Stilphen, "DP Interviews: Mark Lesser", Digital Press (retrieved 2026-10-19): a redesigned Rockwell LED calculator chip; a multiplexing scheme letting the eight digit drivers handle the playfield and score; sound from a single output driving a piezo-ceramic speaker, toggled by the program, "without any sound driver hardware".
- ↑ 4.0 4.1 4.2 Sean Riddle, Auto Race circuit board scans (retrieved 2026-10-19), hosted here as File:Mattel Auto Race circuit board, component side.jpg and File:Mattel Auto Race circuit board, solder side.jpg: display board joined to the main board by a row of pins; one axial electrolytic printed "25V 10µF"; a single chip position and no other integrated circuits.
- ↑ Richard S. Chang and George J. Klose (Mattel, Inc.), US Patent 4,162,792, "Obstacle game", 1979: if 99 seconds pass without four laps, "the digits 99 remain" and "a monotone sound of defeat" continues until the game is turned off.
- ↑ 6.0 6.1 6.2 Handheld Games Museum, "Mattel Auto Race" (retrieved 2026-10-19): the internal speed control, usually set about the middle, can make the game about twice as fast or twice as slow.
- ↑ 7.0 7.1 7.2 7.3 Slashdot, "Retrocomputing Enthusiast Repairs Mattel's 48-Year-Old Handheld Videogame", 9 November 2024 (retrieved 2026-10-19): a broken Auto Race; after an unsuccessful attempt to resolder the connections on the old connector, the owner replaced the 9-volt battery connector, and the game then played.
- ↑ 8.0 8.1 8.2 Sean Riddle, "The First Mattel LED games" (retrieved 2026-10-19): the Mattel games used "unknown Rockwell chips" marked B6000 for Auto Race; Riddle decapped and dumped them to work out their instruction set.
