Mata Hari (Bally, 1978): common faults and replacement boards (Bally MPU)
Does your Bally Mata Hari fail to boot (7 flashes then silence), reset when the ball leaves the saucer, or show flickering lamps on bumper hits? 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.
Mata Hari (Bally, 1978): overview
Released in 1978 on an espionage theme inspired by the famous dancer-spy, Mata Hari is one of Bally's biggest solid-state hits, produced in over 16,000 units. It uses the Bally AS-2518-series MPU.
- Manufacturer: Bally
- Year: 1978
- Electronic system: Bally MPU (AS-2518)
- Type: solid-state pinball
- Theme: espionage / Mata Hari
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 Mata Hari (forum feedback)
- 7 flashes then no power-up tune: the boot sequence stops; points to the MPU (PIA/RAM, battery corrosion).
- Resets when the ball leaves the top saucer: a voltage drop on coil firing; power supply and the C23 capacitor (5 V filter) to rework.
- Lamps flickering on bumper hits: unstable 5 V regulation on the power board.
- Leaked battery on the MPU: corrosion around U10/U11.
- Oxidised or burnt connectors: to replace for a reliable machine.
- Displays with missing segments: displays and MPU to check.
Replacement boards compatible with Mata Hari
- BallyFA — replacement MPU board (battery-free).
- BallyDri — power supply + driver.
- BallyLa_60 — lamp driver.
📚 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 resets and power (C23 capacitor, 5 V regulation), the BallyDri takes over; the lamps via the BallyLa_60. Plug & Play installation, battery-free, free support. Contact us.
FAQ — Mata Hari Bally
My Mata Hari does 7 flashes and won't boot.
The boot sequence stops on the MPU side (PIA/RAM, corrosion). The BallyFA replaces the MPU and boots without a battery.
It resets when the ball leaves the saucer.
A 5 V drop on coil firing; rework the power supply (C23). The BallyDri (power + driver) makes this reliable.
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
- Power off, visual inspection: look for any battery or corrosion damage on your Mata Hari MPU, especially around U10/U11; remove the battery if still present.
- Power: measure the 5 V and check that it reaches the MPU (rework the power/rectifier board and the 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 start-up, credits, coils and displays; reminder: the BallyFA replaces the MPU and boots without a battery. If needed, contact our free support.
