Why Are My Arcade Game Graphics Garbled, Missing, or the Wrong Colors?

By HighScoreSaves Technical Team

Reviewed and updated September 2, 2026

A classic arcade game can still appear to be running while displaying corrupted characters, missing sprites, strange backgrounds, incorrect colors, repeated patterns, or an unstable picture.

These symptoms are commonly described as garbled graphics, but that term can cover several very different problems.

The best first step is to determine what part of the picture is wrong and whether the problem appears to be generated by the PCB or introduced later in the video path.

What Counts as Garbled Arcade Graphics?

Examples can include:

• characters replaced by random patterns;
• sprites that are missing or incomplete;
• duplicated objects;
• incorrect tiles or backgrounds;
• letters or numbers that appear corrupted;
• objects appearing in the wrong locations;
• incorrect or missing colors;
• vertical or horizontal lines through game graphics;
• repeating blocks or patterns; and
• a picture that is recognizable but clearly incorrect.

Other display symptoms—such as rolling, loss of synchronization, or the entire image having an incorrect color balance—can point toward a different part of the video path.

How Does a Classic Arcade PCB Create Graphics?

The exact design varies by game, but an original arcade PCB can use several types of hardware to produce the final image.

These may include:

• program ROMs;
• graphics ROMs;
• RAM or video RAM;
• CPU activity;
• counters and timing circuitry;
• custom ICs;
• color circuitry;
• support logic; and
• video-output circuitry.

The monitor does not usually create the game objects itself. It displays the video signal generated by the arcade hardware.

For the complete signal path, see Arcade Video Signals Explained: RGB, Sync, and How the PCB Connects to the Monitor .

Can Bad Graphics ROMs Cause Garbled Graphics?

Yes.

Many classic arcade boards store graphics-related data in ROM devices. If the PCB cannot correctly access required graphics data, characters, sprites, tiles, or other visual elements can appear incorrect.

However, seeing incorrect graphics does not prove the graphics ROM itself has failed.

Similar symptoms can result from:

• poor ROM socket contact;
• damaged pins;
• broken traces;
• addressing problems;
• data-path problems;
• support-logic faults; or
• incorrect ROM data.

Learn how program, graphics, and sound-related ROMs differ in Original Arcade ROMs Explained .

Can Arcade RAM Cause Graphics Problems?

Yes.

Many arcade systems use RAM for changing display information. Depending on the architecture, RAM can be involved with tile information, sprite positions, attributes, color-related values, temporary display data, or other video functions.

A RAM-related problem can therefore create corrupted or unstable graphics.

As with ROM, the memory device itself is only one possibility. Address lines, data lines, sockets, support logic, traces, and power can produce similar symptoms.

See Arcade RAM Explained: What RAM Does on a Classic Arcade PCB .

Why Are Some Objects Wrong While the Rest of the Screen Looks Normal?

A partially correct picture is useful information.

If backgrounds appear normal but sprites are corrupted—or characters are correct while another graphical layer is wrong—the problem may involve circuitry dedicated to that portion of the display.

Classic arcade boards often generate different visual elements through different memory areas or logic paths.

The exact interpretation is game-specific, so the schematic and service documentation for that PCB become especially valuable when the symptom affects only one visual layer.

Why Are the Colors Wrong?

Incorrect colors can originate on either side of the PCB-to-monitor boundary.

Possible PCB-related areas include:

• color RAM or color-related memory;
• palette or lookup circuitry;
• resistor networks;
• support logic;
• damaged traces; or
• video-output circuitry.

Possible signal-path or display areas can include:

• RGB wiring;
• video ground;
• edge-connector contacts;
• harness connections;
• monitor input connections;
• monitor adjustments; or
• monitor circuitry.

If the entire image is missing one color—for example, everything that should contain red appears incorrect—that is a different symptom from one particular sprite using the wrong colors.

What If the Entire Picture Is Rolling or Unstable?

A rolling, tearing, or non-locking picture may involve synchronization rather than graphics data.

The game can potentially be generating otherwise correct graphics while the monitor is unable to lock properly to the sync information.

That can involve the PCB's sync generation, connector, wiring, adapter, monitor input, compatibility, or monitor itself.

This is why "bad video" and "garbled graphics" should not automatically be treated as the same problem.

Can the Arcade Power Supply Affect Graphics?

Yes.

Digital logic, memory, and video circuitry require correct and stable power.

If the voltage reaching the PCB is low, unstable, or affected by excessive voltage drop, the game can behave unpredictably.

A power problem can potentially create symptoms that resemble memory or logic faults.

Before changing supply adjustments, understand where the voltage is being measured and what the specific hardware requires.

Read Classic Arcade Power Supplies Explained: +5V, +12V, Ground, and Voltage Drop .

Can the Edge Connector Cause Video Problems?

Yes.

Depending on the game, RGB, sync, ground, power, and other signals may pass through the PCB edge connector.

Dirty, oxidized, loose, overheated, or damaged contacts can interfere with the electrical path between the board and cabinet.

Learn more in Arcade Edge Connectors Explained .

Can Test Mode Help Diagnose Garbled Graphics?

Sometimes.

A game's built-in test or service mode may include:

• RAM diagnostics;
• ROM checks;
• color screens;
• character displays;
• crosshatch patterns;
• screen-position tests; or
• other game-specific diagnostics.

A diagnostic screen can help determine whether a symptom affects normal gameplay only or appears consistently in the game's own test patterns.

Read Why Does a Classic Arcade Game Have Test Mode and Service Mode? .

Does Garbled Graphics Mean the Monitor Is Bad?

No.

The monitor is the final major stage of the arcade video path. If the game PCB generates incorrect pixel, tile, sprite, or color information, the monitor can faithfully display that incorrect signal.

Conversely, a perfectly functioning PCB can still produce a poor-looking image if there is a wiring, sync, monitor-input, or monitor problem.

The appearance of the symptom helps determine which side of that boundary should be investigated first.

What If the Graphics Problem Started After Installing an Upgrade Kit?

If the game displayed correctly before an upgrade and the symptom appeared immediately afterward, begin with the hardware that was changed.

Verify:

• the correct kit and PCB compatibility;
• CPU orientation;
• daughterboard orientation;
• Pin 1;
• CPU seating;
• daughterboard seating;
• socket-row alignment;
• bent pins;
• game-specific cables or adapters; and
• any ROM changes specifically required by the installation guide.

Do not immediately adjust the monitor or replace unrelated graphics components.

Use Arcade Game Won’t Boot After Installing an Upgrade Kit: What to Check First as the controlled post-installation troubleshooting starting point.

Use the Exact Game's Kit Page and Installation Guide

HighScoreSaves upgrades are game-specific, so installation requirements can differ substantially between arcade platforms.

For example, owners working with supported original hardware can review the dedicated pages for:

• Pac-Man upgrade kits
• Galaga upgrade kits
• Donkey Kong upgrade kits

The instructions for one game should never be assumed to apply to another PCB.

Document the Symptom Before Changing Anything

Take clear photographs or video showing exactly what the game is doing.

Useful information includes:

• whether the problem appears immediately at power-up;
• whether it changes as the game warms up;
• whether the title screen is affected;
• whether gameplay objects are affected;
• whether colors are missing everywhere or only in certain graphics;
• whether test mode shows the same problem;
• whether sound and controls still function; and
• whether anything was changed immediately before the symptom appeared.

A documented symptom is much easier to compare before and after each troubleshooting step.

Key Takeaway

Garbled, missing, or incorrectly colored arcade graphics can originate in graphics ROMs, RAM, support logic, sockets, PCB traces, power, edge connectors, RGB and sync wiring, or the monitor system.

The shape of the symptom matters. Corrupted game objects, an entire missing color, and an unstable rolling picture are different clues and should not automatically be diagnosed the same way.

Identify the PCB, document the symptom, use built-in diagnostics when available, verify power and connections, and change one thing at a time rather than assuming the monitor—or any single memory chip—is automatically responsible.

Get More Arcade Knowledge

Enjoyed this article? Join the HighScoreSaves newsletter for new Arcade Knowledge articles, kit announcements, installation tips, product updates, and occasional subscriber-only offers.

Join the HighScoreSaves Newsletter

Classic Arcade • Modern Features