The Incredible Hulk (Gottlieb, 1979): Troubleshooting and System 1 Replacement Boards
Is your The Incredible Hulk (Gottlieb, 1979) becomes erratic after warming up, produces only one sound, or tilts on its own? This widebody Gottlieb pinball machine runs on the System 1. Here are the typical issues reported on forums and the battery-free replacement solutions.
The Incredible Hulk (Gottlieb, 1979): Overview
Released in 1979, The Incredible Hulk is a widebody solid-state Gottlieb System 1 pinball machine featuring Marvel's Incredible Hulk — one of the earliest superhero-licensed pinball machines.
- Manufacturer: Gottlieb
- Year: 1979
- Electronic system: Gottlieb System 1
- Type: solid state, widebody, alphanumeric displays
- Theme: superhero, Marvel, The Incredible Hulk

Common Issues (System 1)
The Gottlieb System 1 shares a well-known set of weaknesses regardless of the game:
- Leaking battery: the NiCad battery soldered to the MPU board corrodes traces and components over time. This is the #1 failure — remove it immediately.
- Poor grounds: the original ground wiring is undersized and causes resets and erratic behavior (ground mods are virtually mandatory).
- Corroded connectors: Molex connectors, especially the 46-pin MPU-to-driver connection, lose contact and require re-pinning.
- Power supply: unstable 5V, tired rectifier bridges, and overheating transformers cause crashes.
- Displays: digits that fade, flicker, or freeze at zero.

The Incredible Hulk-Specific Issues (Forum Reports)
- Erratic behavior after warming up: the PROM Z23 (bipolar PROM) overheats and causes bugs; attaching a small heatsink to the PROM helps significantly.
- 5101 RAM and reset circuit: the most common board failures, often worsened by battery corrosion — a battery-free replacement board eliminates the root cause.
- Only one sound plays: solenoids on the driver must be functional (they trigger sounds); also check corrosion around the 5V regulator on the MPU.
- Random tilt: adjust the coin door slam tilt; a buzzing relay that tilts after a few minutes signals a power or ground problem.
- Drop targets won't reset: the U45 + 3055 transistor pair handles the reset — check both.
- Erratic scoring and logic: the MPU ground mod resolves many scoring and logic issues.
Compatible Replacement Boards for The Incredible Hulk
The Incredible Hulk runs on the Gottlieb System 1, a platform known for its fragility (leaking battery, weak grounds, corroded connectors). Pinballs Store offers battery-free replacement solutions:
- Gosof — replacement sound board.

For a dedicated System 1 CPU/driver board, contact us: we'll point you to the best solution for your The Incredible Hulk. Plug & Play installation, battery-free, with free support.
FAQ — The Incredible Hulk Gottlieb
Why does my Hulk become erratic after a few minutes?
Often the PROM Z23 overheating. A small heatsink, ground mods, and — better yet — a replacement board fix the problem permanently.
Do I need to remove the original battery?
Yes, immediately. The original NiCad battery will eventually leak and destroy the board. A battery-free replacement board permanently eliminates the corrosion risk.
Is there a replacement board for The Incredible Hulk?
Yes. Contact us for the System 1 CPU/driver solution that fits; installation is Plug & Play, battery-free, with free support.
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 The Incredible Hulk; remove the NiCad battery if still present.
- Power supply: measure the 5V rail and verify it reaches the MPU (re-solder the voltage regulator or Q1 if voltage drops).
- Grounds: apply ground mods between the boards (CPU, driver, power supply, sound).
- Connectors: re-pin oxidized Molex connectors, especially the MPU-to-driver board connection.
- Displays: never connect or disconnect a display while powered on; test with a known good display.
- Final test: verify startup, credits, solenoids, and displays; if needed, contact free support.
See Also
- Cleopatra (Gottlieb, 1977)
- Close Encounters of the Third Kind (Gottlieb, 1978)
- Totem (Gottlieb, 1979)
- Genie (Gottlieb, 1979)