Black Pyramid (Bally, 1984): Troubleshooting and Bally MPU Replacement Boards
Is your Black Pyramid by Bally not starting, has dead displays, stuck solenoids, or blowing fuses? 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.
Black Pyramid (Bally, 1984): Overview
Released in 1984, Black Pyramid is a Bally machine with an ancient Egypt theme and alphanumeric display. It uses the Bally MPU board (AS-2518 series).
- Manufacturer: Bally
- Year: 1984
- Electronic system: Bally MPU (AS-2518)
- Type: solid state
- Theme: ancient Egypt
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.
Black Pyramid-Specific Issues (Forum Reports)
- Leaking battery on MPU: corrosion around U10/U11 — top priority.
- 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.
- Targets and mechanisms: clean the outhole and target switches.
- Blowing fuses: look for a shorted rectifier or solenoid coil.
Compatible Replacement Boards for Black Pyramid
- 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. 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 — Black Pyramid Bally
My Black Pyramid won't start.
Check the battery and corrosion around U10/U11. The BallyFA replaces the MPU and runs without a battery.
Solenoids are stuck or unresponsive.
On the power side, the driver board is the culprit: the BallyDri (power supply + driver) replaces it.
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 Black Pyramid; 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)?
See Also
- Kings of Steel (Bally, 1984)
- Spy Hunter (Bally, 1984)
- Grand Slam (Bally, 1983)
- X's & O's (Bally, 1984)
