Mattel Basketball Capacitor Replacement Guide

The back of the game in Mattel's leaflet: the battery cover and the 9 V snap. No photograph of an opened Basketball board has been found.

No capacitor values have been published for Mattel Basketball (model 2437). Mattel issued only an instruction leaflet, and no schematic, parts list or photograph of an opened Basketball board has been found. The documented parts are the three dies bonded to the board, a National Semiconductor MM5799 microcontroller, a 4001 and a 74154, on a board marked MA 6017/18/19. Whether the board carries electrolytic capacitors, and of what value, is not recorded in any of these sources. If you open one, record what you find using the steps below.

What is known

• The game runs from one 9 V battery.
• The MM5799 is rated for 7.9 V to 9.5 V between its supply pins and draws 12 mA typically, 18 mA at most, before its outputs are counted.
• Mattel Soccer and Hockey use the same hardware. No capacitor values have been published for Soccer either; see Mattel Soccer Capacitor Replacement Guide.
• Mattel's Auto Race and Baseball, built round Rockwell chips on different boards, each have one 10 µF electrolytic: 25 V on the Auto Race board and 16 V on the Baseball board that Sean Riddle scanned. These are different circuits and say nothing certain about Basketball; see Mattel Auto Race Capacitor Replacement Guide and Mattel Baseball Capacitor Replacement Guide.

Signs that a capacitor needs attention

• Erratic play or a dim display that a fresh battery does not cure. Mattel's leaflet puts a worn battery first for these symptoms, so rule it out before suspecting a capacitor.
• Brown residue or corrosion on the board round a capacitor, or a swollen or leaking can.
• See Capacitor Failure Symptoms.

Reading and recording your board

1. Take the battery out and open the case; see Mattel Basketball General Maintenance for the triangular screws.
2. Photograph both sides of the board in good light before touching anything.
3. Look for electrolytic capacitors: cylindrical cans with a stripe marking the negative lead. Ceramic discs and resistors do not need replacing on age alone.
4. For each electrolytic, note its position, the capacitance, the voltage rating, the temperature rating if printed, and which way the stripe faces.
5. Note the board marking (MA 6017/18/19 on the board MAME's notes describe) and any revision letter.
6. Keep the notes with the photographs.

Replacing a capacitor

1. Use the same capacitance and the same or a higher voltage rating, of a size that fits under the case.
2. The MM5799 die sits under a plastic cover and its bond wires break very easily; the 4001 and 74154 are also bonded to the board. Keep the iron, the desoldering tool and flux away from the bonded chips, and do not lever against them.
3. Match the polarity to your notes and replace one capacitor at a time.
4. Clean off flux with isopropyl alcohol.
5. Fit a fresh battery, checking the snap's polarity first, and check the game against the normal behaviour on Mattel Basketball Troubleshooting Guide: the readout shows the minutes of the first quarter at switch-on and every key moves or shoots.

Related pages

• Mattel Basketball
• Mattel Basketball General Maintenance
• Mattel Basketball Troubleshooting Guide
• Capacitor Failure Symptoms