Solar Fire (Williams, 1981): common faults and System 7 replacement boards
Does your Williams Solar Fire fail to boot, see its flippers drop out when both are pressed together, reset or have no sound? These symptoms are typical of Williams System 7 pinball machines, whose original boards (MPU, Driver, power supply) are now over 40 years old. The good news: the WillFA7 replacement board, Plug & Play and battery-free, brings your machine back to life.
Solar Fire (Williams, 1981): overview
Released in July 1981, Solar Fire is a Williams System 7 pinball machine with a space theme, featuring 3-ball multiball and a digital display. Designed by Barry Oursler, it had a production run of about 782 units.
- Manufacturer: Williams
- Year: 1981
- Electronic system: Williams System 7
- Type: solid-state pinball, 3-ball multiball
- Theme: space / science fiction
Common faults (System 7)
On Williams System 3 to 7, the recurring faults come from ageing: leaking NiCad battery on the MPU (corrosion, the No. 1 cause of dead boards), worn 40-pin MPU↔Driver connector (the best-known weak point), resets/reboots on a 5 V drop (power headers and connectors to be resoldered), tired power-supply capacitors, displays with missing segments, and a solenoid fuse that blows (slingshot or stuck bumper).
Issues specific to Solar Fire (forum feedback)
- Temperamental drop targets: targets that don't reset or no longer register; check the reset coils, switches and springs.
- 3-ball multiball won't start: often the trough or lock switches need cleaning or replacing.
- Resets during play: a 5 V drop caused by the power connectors and the large MPU capacitor.
- No sound: System 7 sound board to be diagnosed (Sound Select signals on the MPU side).
- Overheating general illumination (GI): discoloured GI connectors to replace and sockets to clean.
- Playfield wear: the shooter area and inserts to protect, common on heavily played examples.
Replacement boards compatible with Solar Fire
- WillFA7 — 2-in-1 board (MPU + Driver) compatible with System 3 to 7, System 7 included.
📚 Further reading: Guide: which board for a Williams System 3 to 7?
The WillFA7 replaces the original MPU and Driver board (boot-up, logic resets, coil and multiball driving, battery-free memory) and removes the fragile 40-pin ribbon. The sound board, the drop targets and the GI must still be maintained separately; our support team will guide you.
Plug & Play installation, battery-free, free tutorials and support. Contact us.
FAQ — Solar Fire Williams
My Solar Fire won't boot, what should I do?
First check the original battery (corrosion) and the 40-pin connector. The WillFA7 replaces the MPU and Driver and boots without a battery.
My flippers die when I press both at once.
Typical of a tired System 7 MPU (capacitor). The WillFA7, which replaces the MPU, eliminates this weak point.
Is the WillFA7 compatible with System 7?
Yes. It covers System 3 to 7, System 7 included, and drives the logic, multiball and coils.
Should I keep the original battery?
No. The WillFA7 works without a battery and removes the No. 1 cause of corrosion on System 7.
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 trace of battery leakage or corrosion on the MPU of your Solar Fire; remove the NiCad battery if still present.
- Power supply: check the 5 V and the fuses; resolder the power and MPU headers if the voltage drops or the game resets.
- Connectors: re-pin the oxidised Molex connectors, especially the MPU↔Driver link.
- Coils: check the solenoid fuses and the switches (stuck slingshot) before powering back on.
- 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; remember that the WillFA7 replaces MPU + Driver. If needed, contact free support.
See also
- Black Knight (Williams, 1980)
- Jungle Lord (Williams, 1981)
- Pharaoh (Williams, 1981)
- Barracora (Williams, 1981)
