A follow-up to the article Lamps, which explains why #47 is a better choice than #44. Here is the next step: LEDs. Which ones fit, what goes wrong, and where the swap is really worth it.
Why you should consider it
A pinball machine from the '80s has 100 to 150 incandescent lamps. With #44s they draw around 150 W just for the lighting, and their heat is the reason the playfield plastics yellow and warp, the inserts lift, and the GI connectors burn. An LED draws one tenth of the current and gives off almost no heat. On the other hand, it changes the look of the machine, and not always for the better. The right answer is usually "LEDs in some places, incandescent in others".
Which LED for which lamp
| Incandescent lamp | Base | Replacement LED | Where you find it |
|---|---|---|---|
| #44, #47 | BA9S (bayonet) | BA9S LED, 6.3 V | GI and inserts in most older machines |
| #555 | Wedge T10 | Wedge T10 LED, 6.3 V | Inserts and GI in System 11, WPC and later |
| #89, #67 | BA15S (bayonet, large) | BA15S LED flasher, 12–13 V | Flash lamps in System 11 and Bally |
| #906 | Wedge T5 | Wedge T5 LED flasher, 13 V | Flash lamps in WPC |
| #455 | BA9S | BA9S LED with built-in flashing | The "blinking" #44, a few spots in every machine |
Always buy LEDs made for pinball machines, not generic automotive LEDs: they have the right voltage (6.3 V, not 12 V), the right polarity for the lamp matrices, and usually built-in rectification for the AC general illumination.
The three problems you will run into
1. Flicker in the GI
In most machines up to and including WPC, the general illumination is 6.3 V AC. An incandescent lamp does not have time to go dark at 50 Hz; an LED does. The result is a flicker that some people cannot see and that drives others mad. Solution: LEDs with built-in rectification and a capacitor (they are called "non-flicker", "anti-flicker" or "AC compatible"). They cost a bit more and are worth it.
2. Ghosting in the controlled lamps
The controlled lamps are in a matrix and are lit by very fast scanning. An LED lights up with a tiny current, so it appears to glow faintly even when it is supposed to be off, especially when its neighbours in the same row are lit. That is ghosting. Where it shows up: mainly in WPC and System 11. Solutions: LEDs with a resistor or an "anti-ghost" circuit, or, on WPC, a game ROM with the fix (the "ghost-busted" ROMs). On Bally -17/-35 and Williams System 3-7 ghosting is rare, because their drivers are different.
3. It changes the colour of the artwork
An incandescent lamp is warm, yellowish. A "cool" white LED makes the backglass and the playfield look like a hospital. The rule: in the backbox and in the GI use warm white so the artwork stays the way the artist designed it. In the inserts you can put LEDs in the colour of the insert (red in red, green in green), which gives a cleaner colour, or white, which lets the plastic colour the light. "Frosted" (diffused) LEDs spread the light and do not make bright hot spots: generally better than "clear" ones in inserts and GI.
Where it is worth it and where it is not
| Location | Worth it? | Why |
|---|---|---|
| GI in the backbox | Yes | Many lamps, a lot of heat next to a backglass that is flaking. Warm white, non-flicker. |
| GI on the playfield | Yes, in moderation | Saves the plastics from yellowing. Warm white. Do not fit the brightest ones. |
| Inserts | Yes | Cleaner colours, less heat under the inserts. Watch out for ghosting. |
| Flash lamps | Yes | LED flashers are faster and do not burn the plastics. |
| Lamps under the playfield for "magic" effects | No | Those "ultra bright" kits make the machine look like a Christmas tree. The playfield was not designed for that kind of light. |
| A machine in original condition for a collection | Maybe not | Some collectors want incandescent. If you sell, keep the old lamps. |
Practical tips
- Buy 10 pieces first, try them in your machine, and then order the rest. Photos on the internet do not tell the truth about the colour.
- LEDs have polarity. If one does not light up, turn it 180 degrees in the socket. With wedge bases that is easy; with bayonet bases it takes a little care.
- Do not mix incandescent and LED in the same GI string if the GI has dimming (System 11 and later): the incandescent will dim, the LED will not.
- After the swap, the GI fuses may now be oversized for the current that flows through them. That is fine, but never fit a bigger one than the manual says.
- A full LED set for an old machine costs 60 to 120 euros, depending on the shop and the type.