Types of lightbulbs used in pinball machines

Many people view a pinball machine as a big box full of blinking lights, and they're absolutely right. But what kind of lightbulbs are actually used? If you're new to pinball, you might wonder which lamps are installed and where to buy them.

Here's my first piece of advice: buy your bulbs from a dedicated pinball store. They stock the correct parts at fair prices. Avoid general hardware stores, DIY shops, or large lighting retailers. They often don't carry these bulbs, and special orders can cost up to ten times more.

Quick summary: Most classic pinball machines with incandescent bulbs use type #44 (bayonet) or #555 (wedge). For flasher lamps, types #89 (bayonet) and #906 (wedge) are common. Always buy from a specialized pinball parts dealer (affiliate link).

Different circuits

Most pinball machines use two types of lighting circuits: general illumination (GI) and controlled lighting.

• Controlled lights can blink or turn on/off individually. They highlight features on the playfield, indicate status, or guide gameplay.
• General illumination simply lights up the playfield. These lamps are grouped and controlled together, not individually.

Older electro-mechanical machines had one string for the backbox and one for the playfield. Later more strings were added, as the number of lights used on the game increased. WPC games used 5 strings, two for the backbox and three for the playfield. Usually these playfield strinfs were split up into zones: top, center, and bottom, but sometimes left and right sides for dynamic effects.

Controlled lights typically run on 6.3V DC, while GI uses 6.3V AC. This distinction AC or DC matters when replacing incandescent bulbs with LEDs.

Exceptions exist: Whitewater uses 12V bulbs in the topper that resemble #555 bulbs. Creature from the Black Lagoon has small bulbs in the ramp. Pinball 2000 machines use only controlled lighting. Jersey Jack Pinball uses 12V for GI, and Stern machines since 2015 use 5V. Lately some manufacturers don't have GI circuits anymore, all their leds are individually controlled lights, allowing for more impressive lightshows.

Lights and flashers

From left to right: wedge lamp type #555 and flasher #906, bayonet lamp type #44 and flasher #89.

Older machines often used only #44 bayonet bulbs at 6.3V. Some players switched to #47 bulbs, which draw less current and produce less heat, but they’re also dimmer. This change helped prevent damage to plastics and connectors.

Nowadays, installing #47 bulbs isn't necessary. A better solution is using LED bulbs to save energy and protect your game of heat damage.

In the 1980s, manufacturers introduced #555 wedge bulbs, especially in areas accessible from the top of the playfield or mounted on circuit boards. Machines before that didn't have pcbs for lights, each lamp had its own separate metal holder.

In the second half of the 1980ies, flasher lamps were added. These are larger bulbs like #89 (bayonet) and #906 (wedge), rated at 12V. These flash briefly to draw attention, using short pulses of up to 20V. The pulse is short enough not to damage the bulb but bright enough to stand out. The heat of a locked on flasher can melt nearby plastics.

Flasher circuits resemble solenoid coil circuits more than regular lamp circuits. Bayonet flashers (#89) are typically under the playfield, while wedge flashers (#906) are found on ramps and plastics, often with bright covers.

Flashers on the playfield usually have such a bright plastic cover over them.

LEDs

Around 2005, LEDs became popular aftermarket upgrades. Incandescent bulbs could be replaced with brighter, colored LEDs. Early versions were extremely bright, some games practically required sunglasses!

Over time, more refined LED types emerged, better suited for playfields and specially designed for use in pinball machines. Manufacturers began switching to LEDs around 2010. Some retained the old logic and simply swapped bulbs for white LEDs. Newer companies like Spooky and Jersey Jack redesigned circuits to support RGB LEDs, and their games stood apart in a row of games with their spectacular lightshows in attract mode.

Simple leds can only shine in one color. RGB LEDs are a combination and they contain red, green, and blue diodes in one unit. By adjusting the brightness of each, they can generate a wide range of colors in all combinations. GI lighting can now shift colors dynamically, and inserts can change meaning during gameplay.

Green is good, red is bad, mmkey ?

RGB bulbs in the newer games are often specific to the manufacturer or model. Replacing them requires finding the exact match.

Replacing incandescant bulbs by leds

There's now a thriving aftermarket for LED replacements. LEDs come in various colors and brightness levels. Choosing the right one depends on its location and desired effect.

As said above, there's now a huge aftermarket business providing leds for when people want to replace the incandescent bulbs. Leds are available in different colors and brightness. Which led exactly to use, mostly depends on the place of the led on the playfield and what effect you want to achieve.

Different types of led lamps. Many more types exist with more emitting parts, clear (or no) covers, ..

Unfortunately, you can't just swap any incandescent bulb with a random LED. It's more complicated than selecting a nice new color. Compatibility depends on the LED type, the machine, and the original bulb's function.

Common issues include:

• Strobing: rapid flickering due to circuit timing.
• Ghosting: LEDs stay dimly lit when they should be off.
• Polarity problems: LEDs only work when inserted in the correct direction.

Cheap LEDs may not light up at all due to polarity. Incandescent bulbs glow gradually, the internal wire start to glow when they receive power, and they become more bright the more power they receive. When the power suddenly is cut off, the glowing wire will cool down fast but gradually. LEDs work totally different, they switch on instantly once they receive a lower level of power. Below that level, they remain dark. When they are lit and the power is cut off, they stop emitting immediately. This difference affects how they behave in circuits and how a player views them.

When buying from general stores like AliExpress, check for terms like 'AC', 'non-ghosting', and 'non-flickering'. Spending a few extra dollars is worth it to ensure compatibility. Buying the cheapest you can find can be wasted money if they're not compatible at all with your pinball machines.

Polarity Problems

All LEDs operate on DC power. Cheap LEDs may only accept DC input. If inserted incorrectly, they won’t light up, as the polarity is not aligned. Like a battery, there is a positive and negative side, and it won't work in the opposite direction. In AC circuits, these DC LEDs may appear dim since they only illuminate half the time.

At minimum, buy LEDs marked 'AC'. Avoid the cheapest options.
With leds from a pinball parts shop (affiliate link) you're sure that the parts are made for pinball machines.

Strobing or flickering leds

Most pinball LEDs marked 'AC' include internal components to convert AC to DC. However, they still flicker due to the nature of AC power: 60Hz in the US, 50Hz in Europe. AC is a sinewave that goes up and down. The led quickly goes out each time the wave passes the center. This results in visible flickering at 100–120 times per second.

Non-flickering LEDs contain capacitors that smooth out the signal. They have like a small battery in them so they don't dim completely during a sine wave. However they're not the perfect solution. In some games with complicated lightshows they're not sensitive enough.

Strobing is a type of flickering that can occur on certain types of pinball machines. This is caused by how they pinball machine electronics circuit drives the lamps. Electronics don't have an on/off switch that works continuously. They will also quickly pulse the lights on when they have to be lit. GI circuits can be dimmed, this dimming is done by switching the lights to 'off' a certain period of time (milliseconds). With controlled lamps in a matrix, the pinball machine will also very quickly tell each lamp to be 'on'. The combination of at what speed the pinball machine does this and how sensitive the leds are may also cause flickering.

Classic electronic Bally / Stern games (1977-1985) have a similar hardware flickering issue. Because leds draw a lot less current than regular bulbs, the electronics that drive the controlled leds are confused and cause flickering.

Ghosting leds

Ghosting occurs when LEDs remain dimly lit even when turned off. This happens because some circuits retain residual voltage, which is enough to activate sensitive LEDs. It usually happens when you replace controlled lamps (machines after 1985) with leds.

Incandescent bulbs require higher voltage to glow, so they don’t show this effect. Ghosting depends on hardware and sometimes software. Some controlled circuits don't go completely to 0 volts when they go out, there is some rest (ghost) voltage still in the circuit that is high enough to make leds shine a bit. In some cases, updating the game’s ROM can fix it.

Anti-ghosting LEDs exist and often help, but they may interfere with light shows that use dimming effects.

If you're looking for pinball parts, then check out Pinballshop.nl (affiliate link).