Fireball II (Bally, 1981): Troubleshooting and Bally MPU Replacement Boards
Is your Fireball II by Bally not starting, has a silent multiball, a finicky center post, or dead displays? These symptoms are typical of Bally microprocessor pinball machines whose original MPU board is now over 40 years old and almost always suffers from a leaking battery. The good news: the BallyFA replacement MPU board, Plug & Play and battery-free, brings your machine back to life.
Fireball II (Bally, 1981): Overview
Released in 1981, Fireball II is a Bally machine with 3-ball multiball, a captive ball, and the "Little Demon" raising center post. It uses the Bally MPU board (AS-2518 series).
- Manufacturer: Bally
- Year: 1981
- Electronic system: Bally MPU (AS-2518)
- Type: solid state, multiball
- Theme: fireball / fantasy
Common Issues (Bally MPU)
On Bally microprocessor pinball machines (1977-1985), recurring failures stem from aging: leaking battery on the MPU (corrodes traces and sockets around U10/U11 — the #1 cause of dead boards), worn PIA 6821 chips (U10/U11) (oxidized pins, machine won't boot), failed 5101 RAM and sockets, oxidized or burnt MPU/power connectors (look for heat marks), displays with missing segments, and power supply/driver board (rectifier, fuses, solenoid transistors) needing attention.
Fireball II-Specific Issues (Forum Reports)
- 3-ball multiball won't launch: check lock and trough switches.
- Finicky "Little Demon" (center post): check the post's coil and switch.
- Leaking battery on MPU: corrosion around U10/U11.
- Dead or partial displays: check the display and MPU power supply.
- Erratic or dead solenoids: driver board (transistors, fuses) needs servicing.
- Oxidized or burnt connectors: need replacing (re-pinning) to stabilize the machine.
Compatible Replacement Boards for Fireball II
- BallyFA — replacement MPU board (battery-free).
- BallyDri — power supply + driver board.
- BallyLa_60 — lamp driver board.
📚 Learn more: Guide: Which MPU board for a Bally (1977-1985)?
The BallyFA replaces the original MPU board (startup, game logic, battery-free memory) and eliminates the battery — the #1 cause of corrosion, including multiball logic. For solenoids and power, the BallyDri takes over; lamps via the BallyLa_60. Installation is Plug & Play, battery-free, with free support. Contact us.
FAQ — Fireball II Bally
The "Little Demon" center post doesn't work.
Check the post's coil and switch. On the logic side, the BallyFA stabilizes solenoid control.
My Fireball II won't start.
Check the battery and corrosion around U10/U11. The BallyFA replaces the MPU and runs without a battery.
Is the BallyFA compatible with my Bally?
Yes, for all Bally microprocessor machines (1977-1985). If in doubt, contact us.
Do I need to keep the original battery?
No. The BallyFA runs without a battery and eliminates the #1 cause of corrosion.
How long does installation take?
Installation is Plug & Play: just a few minutes, no soldering required, with tutorials and free support.
Does a battery-free board retain settings and high scores?
Yes. Modern replacement boards use NVRAM: no battery, no corrosion, and settings are preserved when powered off.
Step-by-Step Diagnostics
- With power off, visual inspection: look for any signs of battery leakage or corrosion on the MPU of your Fireball II; remove the original battery if still present.
- Power supply: measure voltages (especially 5V) and verify they reach the MPU; check the rectifier and power board fuses.
- MPU components: inspect the PIA 6821 chips (U10/U11) and the 5101 RAM, often corroded by battery leakage.
- Connectors: re-pin oxidized or burnt connectors, especially between the MPU and power supply.
- Displays: check display power supply; test with a known good display.
- Final test: verify startup, credits, solenoids, and displays; the BallyFA replaces the MPU battery-free; if needed, contact free support.
Useful Guides
- How much does pinball machine repair cost? A price guide
- How much is my pinball machine worth? Value and estimation
- Pinball machine leg sizes: the complete guide
- Which MPU board for a Bally (1977-1985)?
