Contact (Williams, 1978): faults and replacement boards System 4
Does your Williams Contact reset when you operate the flippers, no longer start or display weak digits? These symptoms are typical of Williams System 4 pinball machines, whose original boards (MPU, Driver, power supply) are now over 40 years old. Good news: the WillFA7 replacement board, Plug & Play and battery-free, gives your machine a second life.
Contact (Williams, 1978): overview
Released in 1978, Contact is a Williams System 4 pinball machine on a communication theme. A title representative of the brand's first solid state generation.
- Manufacturer: Williams
- Year: 1978
- Electronic system: Williams System 4
- Type: solid state electronic pinball
- Theme: communication
Common faults (System 4)
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), connectors that heat up or burn (power supply) and cracked connector solder joints, resets/reboots on 5 V drop (power supply and MPU headers to be resoldered), rectifier bridge that fails into a short circuit (Williams did not fit a fuse between transformer and bridge), displays with missing segments or digits (connectors to be cleaned), and 28 V solenoid fuse that blows (stuck slingshot).
Issues specific to Contact (forum reports)
- Reset when you operate the flippers: typically a 5 V that is too low (measured down to 4.74 V); resoldering the connections of the power supply 5 V connector restores ~4.96 V and the game works.
- Weak displays / fading digits: a frequent connection problem on System 4 — clean and reseat the connectors.
- Locked MPU: only the GI lights up, the game does not start.
- Power connectors to redo: tired headers, cracked solder joints.
- NiCad battery on the MPU: corrosion to neutralise absolutely.
Replacement boards compatible with Contact
- 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 (start-up, logic resets, coil driving, memory without battery). Purely power-supply faults (rectifier bridge, power connectors) still need to be dealt with on the power supply side; our support will guide you.
Plug & Play installation, battery-free, tutorials and free support. Contact us.
FAQ — Contact Williams
My Contact resets when I press the flippers.
The 5 V drops. Resolder the power supply 5 V connector; if the MPU is tired, the WillFA7 replaces MPU and Driver for stable operation.
My displays fade.
Clean and reseat the display connectors. A replacement MPU then makes the driving reliable.
Only the general illumination lights up.
The MPU is probably locked. The WillFA7 replaces it and makes start-up reliable.
Should I keep the original battery?
No. The WillFA7 works without a battery and eliminates the no. 1 cause of corrosion on System 4.
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 trace on the MPU of your Contact; remove the NiCad battery if it is still present.
- Power supply: check the 5 V and the fuses; resolder the power-supply 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; 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
- Lucky Seven (Williams, 1978)
- World Cup (Williams, 1978)
- Disco Fever (Williams, 1978)
- Pokerino (Williams, 1978)
Sources & further reading
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