Black Knight (Williams, 1980): common faults and System 7 replacement boards
Does your Williams Black Knight have a stuck Magna-Save, fail to boot, reset or lose its multiball? 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.
Black Knight (Williams, 1980): overview
Released in 1980 and designed by Steve Ritchie, Black Knight is a milestone in pinball history: the first game with a multi-level playfield and the first to introduce Magna-Save (magnetic ball save), with multiball and speech. An iconic System 7 best-seller.
- Manufacturer: Williams
- Year: 1980
- Electronic system: Williams System 7
- Type: solid-state pinball, multiball, Magna-Save, multi-level playfield
- Theme: medieval / knight
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 Black Knight (forum feedback)
- Magna-Save staying on: the magnet stays active and you have to restart the machine; the cause is a sticking relay (contacts to clean/file), sometimes IC3 to replace.
- Magna-Save not working: often corrosion in the head-to-cabinet connector, or the button wires to resolder on both sides.
- Driving the magnets: the magnets draw too much current for the Driver board — a transistor controls a relay; make sure the ground (white wire with a red stripe) is firmly tightened under the backbox nut.
- No switch-matrix signal at the cabinet Magna-Save buttons: the buttons no longer respond, to be diagnosed on the switch-matrix side.
- Game won't start even after MPU/Driver overhaul: a missing blanking signal, to be investigated precisely.
- Speech and general illumination (GI): the System 7 GI connectors overheat and darken; the sound/speech board is repaired separately.
Replacement boards compatible with Black Knight
- WillFA7 — 2-in-1 board (MPU + Driver) compatible with System 3 to 7, System 7 included.
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 magnet relay's control transistor is on the Driver board, so it is renewed; the relay itself, the wiring, the ground, the sound/speech board and the GI, however, still need to be checked separately. Our support team will guide you.
Plug & Play installation, battery-free, free tutorials and support. Contact us.
FAQ — Black Knight Williams
My Magna-Save stays on or no longer responds.
Often a sticking relay (contacts to clean) or a corroded head-to-cabinet connector. The control transistor is on the Driver board, which the WillFA7 replaces; the relay, wiring and ground still need checking.
My Black Knight won't start even after a board overhaul.
Check the blanking signal and the 5 V supply. The WillFA7 replaces MPU and Driver in one go and removes the 40-pin ribbon, eliminating many causes.
Is the WillFA7 compatible with System 7 and multiball?
Yes. The WillFA7 covers System 3 to 7, System 7 included; it drives the game 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 Black Knight; 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
- Jungle Lord (Williams, 1981)
- Pharaoh (Williams, 1981)
- Solar Fire (Williams, 1981)
- Barracora (Williams, 1981)
