Pokerino (Williams, 1978): faults and replacement boards System 4

Is your Williams Pokerino no longer starting, resetting, with a shorted rectifier bridge or burnt coils? These symptoms are typical of Williams System 4 pinballs, 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.

Pokerino (Williams, 1978): overview

Released in 1978, Pokerino is a Williams System 4 pinball on the poker and cards theme. A well-liked title from the brand's first solid-state generation.

• Manufacturer: Williams
• Year: 1978
• Electronic system: Williams System 4
• Type: electronic pinball (solid state)
• Theme: poker / cards

Common faults (System 4)

On Williams System 3 to 7 machines, recurring faults come from ageing: leaking NiCad battery on the MPU (corrosion, the no.1 cause of dead boards), connectors that overheat or burn (power supply) and cracked connector solder joints, resets/reboots on a 5 V dropout (power-supply and MPU headers to be resoldered), rectifier bridge failing short (Williams fitted no fuse between transformer and bridge), displays with missing segments or digits (connectors to be cleaned), and 28 V solenoid fuse blowing (stuck slingshot).

Issues specific to Pokerino (forum feedback)

• Shorted rectifier bridge: a Williams design flaw (no fuse between transformer and bridge); the large lamp and coil power bridges often fail.
• 40-pin interconnect ribbon: the link between the CPU board and the Driver board often needs replacing.
• Dead transistors: faulty driving transistors on the Driver board.
• Burnt coils under the playfield: a consequence of stuck driving or an unsuitable fuse.
• NiCad battery on the MPU: corrosion that absolutely must be neutralised.

Replacement boards compatible with Pokerino

• 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, battery-free memory), integrating the MPU↔Driver link. Pure power-supply faults (rectifier bridge, power connectors) still need handling on the power-supply side; our support guides you.

Plug & Play installation, battery-free, free tutorials and support. Contact us.

FAQ — Pokerino Williams

My rectifier bridge is shorted.
This is a classic Williams flaw (no dedicated fuse). Replace the bridge on the power-supply side; the WillFA7 then makes the logic and driving reliable.

My MPU-Driver ribbon is damaged.
The WillFA7 combines MPU and Driver on a single board, removing the fragile 40-pin ribbon.

Some coils have burnt out.
Often a stuck transistor. The WillFA7 replaces the Driver stage; replace the damaged coil.

Should I keep the original battery?
No. The WillFA7 runs without a battery and permanently removes the no.1 cause of corrosion on System 4 machines.

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

1. Power off, visual inspection: look for any battery or corrosion trace on the MPU of your Pokerino; remove the NiCad battery if it is still present.
2. Power supply: check the 5 V and the fuses; resolder the power-supply and MPU headers if the voltage drops or the game resets.
3. Connectors: re-pin the oxidised Molex connectors, especially the MPU↔Driver link.
4. Coils: check the solenoid fuses and the switches (stuck slingshot) before powering back on.
5. Displays: never plug or unplug a display while powered; test with a known-good display.
6. 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)
• Contact (Williams, 1978)
• Disco Fever (Williams, 1978)

Sources & further reading

• Pinside forum — Pokerino
• IPDB — Internet Pinball Database
• OPDB — Open Pinball Database