Future Spa (Bally, 1979): common faults and replacement boards (Bally MPU)

June 26, 2026

Does your Bally Future Spa fail to boot, have dead displays or runaway coils? These symptoms are typical of microprocessor Bally pinball machines, whose original MPU board is now over 40 years old and almost always suffers from a leaked battery. The good news: the BallyFA replacement MPU board, Plug & Play and battery-free, brings your machine back to life.

Future Spa (Bally, 1979): overview

Released in October 1979 on a futuristic spa theme, Future Spa is a Bally widebody pinball produced in around 6,400 units. It uses the Bally MPU of the AS-2518 series.

Manufacturer: Bally
Year: 1979
Electronic system: Bally MPU (AS-2518)
Type: solid-state pinball, widebody
Theme: futuristic spa

Bally MPU board (BallyFA) — Future Spa — The MPU board drives the whole Bally pinball.

Common faults (Bally / Stern)

On microprocessor Bally and Stern games (1977-1985), the recurring faults come from ageing: leaking battery on the MPU (corrosion of traces and sockets around U10/U11, the No. 1 cause of dead boards), tired 6821 PIAs (U10/U11) (oxidised legs, no boot), 5101 RAM and sockets to replace, MPU/power connectors oxidised or burnt (look for heat marks), displays with missing segments, and the power/driver board (rectifier, fuses, coil transistors) to rework.

Issues specific to Future Spa (forum feedback)

Manual inaccurate about the rectifier's J3 connector: the actual wiring differs from the documentation; check the wires actually present before replacing.
Leaked battery on the MPU: corrosion around U10/U11.
Dead or partial displays: display and MPU power to check.
Runaway or dead coils: driver board (transistors, fuses) to rework.
Oxidised or burnt connectors: to replace (repin) for a reliable machine.
Blowing fuses: a shorted rectifier or coil to track down.

Checking a Bally board with a multimeter — Future Spa — The multimeter: essential to check the power supply and diagnose the MPU.

Replacement boards compatible with Future Spa

BallyFA — replacement MPU board (battery-free).
BallyDri — power supply + driver.
BallyLa_60 — lamp driver.

BallyDri power and driver board for Bally — Future Spa — The BallyDri: replacement power and driver board, Plug & Play installation.

📚 Further reading: Guide: which MPU board for a Bally / Stern (1977-1985)?

The BallyFA replaces the original MPU board (boot-up, logic, battery-free memory) and removes the battery, the No. 1 cause of corrosion. For the coils and power, the BallyDri takes over; the lamps via the BallyLa_60. Plug & Play installation, battery-free, free support. Contact us.

FAQ — Future Spa Bally

My Future Spa won't boot.
Check the battery and corrosion around U10/U11. The BallyFA replaces the MPU and works without a battery.

The J3 connector doesn't match the manual.
It's known on Future Spa: rely on the actual wiring. On the power side, the BallyDri replaces the rectifier/driver board.

Is the BallyFA compatible with my Bally?
Yes, for microprocessor Bally/Stern games (1977-1985). If in doubt, contact us.

Should I keep the original battery?
No. The BallyFA works without a battery and removes the No. 1 cause of corrosion.

How long does it take to install a replacement board?
Installation is Plug & Play: a few minutes, no soldering, with tutorials and free support.

Does a battery-free board keep the settings and high scores?
Yes. Modern replacement boards use non-volatile memory: no more battery, no more corrosion, and the settings are kept when powered off.

Step-by-step diagnosis

Powered off, visual inspection: look for any battery or corrosion trace on your Future Spa's MPU, especially around U10/U11; remove the battery if it is still present.
Power supply: measure the 5 V and check it reaches the MPU (rework the power/rectifier board and fuses if the voltage drops).
Grounds and connectors: rework the oxidised or burnt MPU/power connectors (heat marks) between the boards.
MPU components: check the 6821 PIAs (U10/U11) and the 5101 RAM, often tired or corroded by the battery.
Displays: never plug or unplug a display while powered on; test with a known-good display.
Final test: check boot-up, credits, coils and displays; reminder: the BallyFA replaces the MPU and boots without a battery. If needed, contact our free support.