Siegecraft - An Eclectic and Undecided Website

There are a number of reasons people choose to go with LED's. They offer significant reductions in power useage, which is good both for your electric bill as well as reducing the power load on the various lighting circuits that always seem to be pushed to their limits. They help to eliminate excess heat that contributes to damage to playfield plastics, playfield inserts, backglasses, translights, circuit boards, etc. My own tests have shown that you can reduce the power use from a machine by 60% or more, with internal backbox temperature dropping from over 120 degrees almost to ambient room temperature.

They significantly reduce maintenance needs, as you almost never need to replace an LED. Just think about how often you need to replace those #44 or #555 incandescent lamps. Some locations can be difficult to access, while risking damage to valuable ramps or other components that you need to move out of the way.

Totally opinion based, but many people prefer the look of LED's. They offer a variety of lensing patterns that can be used to good effect, as well as very rich colors that offer much more depth than an incandescent can offer. However, this can take a lot of trial and error to get a look that you like.

The same can be said for the extra brightness that LED's can offer. They are avaialable in packages that range from approximately the same brightness as an incandescent bulb, all the way to giving you sunburn with too much exposure (And that's not an exaggeration, I have fish tank LED's that really can give me a sunburn. Great for raising corals though). Some people like it, some people don't.

Pros and Cons
Pro There are a number of reasons people choose to go with LED's. They offer significant reductions in power useage, which is good both for your electric bill as well as reducing the power load on the various lighting circuits that always seem to be pushed to their limits. They help to eliminate excess heat that contributes to damage to playfield plastics, playfield inserts, backglasses, translights, circuit boards, etc. My own tests have shown that you can reduce the power use from a machine by 60% or more, with internal backbox temperature dropping from over 120 degrees almost to ambient room temperature. They significantly reduce maintenance needs, as you almost never need to replace an LED. Just think about how often you need to replace those #44 or #555 incandescent lamps. Some locations can be difficult to access, while risking damage to valuable ramps or other components that you need to move out of the way. Totally opinion based, but many people prefer the look of LED's. They offer a variety of lensing patterns that can be used to good effect, as well as very rich colors that offer much more depth than an incandescent can offer. However, this can take a lot of trial and error to get a look that you like. The same can be said for the extra brightness that LED's can offer. They are avaialable in packages that range from approximately the same brightness as an incandescent bulb, all the way to giving you sunburn with too much exposure (And that's not an exaggeration, I have fish tank LED's that really can give me a sunburn. Great for raising corals though). Some people like it, some people don't.
Con Poor LED choices can just plain look bad, be it the color or brightness. Sometimes it's simply that you may not like the look, Ghosting: This is a compatibility issue with some machines that varies in severity. Ghosting is exhibited by a lamp that should be totally turned off, but is still lit to some degree. Sometimes this is a software issue with the machine, sometimes hardware, but still a pain in the butt. Dealing with ghosting is possible, but varies from machine to machine in how to approach it. Flicker: More an issue with using older LED designs, and comes from a couple of sources. In GI circuits, it's caused by the 60hz power cycle of the A/C power being used, meaning that the LED actually blinks 60 times per second. With insert lamps it's due to the PWM cycle that the lamp matrix uses, where 18 volts of DC power is pulsed on a 1/3 duty cycle into the lamps to give an effective voltage of 6v. But again, it causes a very fast strobe effect that can be unpleasant. Constant-On: Different than Ghosting, a constant-on situation is were an LED is always turned on. Generally this is caused in circuits that are kept "warm", meaning there is always a low level of voltage passing through the circuit. Early Williams solid state machines are a great example, where the flasher lamp circuits are kept warm to help with lamp longevity and responsiveness. Too Fast response times: This is the root cause of ghosting and flicker problems too, but is worthy of being its own issue. LED's just turn on and off a heck of a lot faster than an incandesent bulb. When seen in a flashing insert, it can be a much harsher effect coming from an LED.
Problem Workarounds
Ghosting:	The most complex issue with LED's for sure, this one is generally a software issue tied to the PWM system used on insert lamps. The matrix lamps are worked in a sequence, and aren't all pulsed at the same time. When one column turns off, another turns on. The problem comes in the sequencing and lag in the circuitry. Early WPC machines have a software glitch, and the sequencing is a bit screwy, which results in very nasty ghosting. Somewhere around 1995 the software was updated to deal with this. Unfortunately, for older machines, it requires a software update that isn't currently available. Should the patching software become avaialble, I'll pass the information on. Some older machines also suffer from minor ghosting, I can see it very lightly on my Black Knight for instance. Again, I have no hardware solution to offer to eliminate it. I have some theories, but none that I can confirm will work. ABlazer does claim that their "Ghost Buster" LED's will eliminate this (which is where the name came from), and field reports so far seem positive. Users of Noflix Plus however have not had as much luck from what I have been seeing.
GI Flicker	GI flicker is mostly an issue with older LED's that feature no additional circuitry other than the LED and voltage drop resistor. What you are seeing is the 60hz cycle of the AC power input leading to the LED, this means it's flashing 60 times per second. It may seem very fast, but your eyes and brain can discern this flashing, particularly if the ball is moving very rapidly. It's also the reason that cheap LED christmas lighting and flourescent lamps can be hard to look at. In Europe, where 50hz AC power is the norm, it means the flash rate is slower and even more noticeable. There are two ways to deal with this. Newer designs feature, at minimum, an internal rectifier that converts the AC power to DC. Cointaker, I believe has rectifiers in their entire line of LED's, look for the "non-polarized" label. This would result in a 120hz (100hz in Europe) strobe rate instead of 60hz. While still there, it is fast enough that the vast majority of people will no longer be affected by it. More advanced LED's, such as the ABlaze "Ghost Buster" or the Pinball Center EU "Noflix Plus" feature even more advanced circuitry that eliminates the flicker totally. Alternatively you can deal with this on older solid state machines via additional hardware if the GI lighting isn't controlled via anything more complex than a relay. The addition of a full wave rectifier with smoothing capacitor to your GI lighting circuit will convert it over to a steady DC voltage, eliminating the flicker totally. Note though that this applies mostly to older solid state machines. Williams WPC machines, for example, cannot use this method due to the SCR controlled GI lighting. Some aftermarket power supply boards also feature DC conversion circuitry which does this for you.
Insert Flicker	This is a different beast than the GI flicker, and more difficult to deal with. Controlled matrix lighting generally runs at 18v, not 6v, and is pulsed at a 1/3 duty cycle. This is called "Pulse Width Modulation", or PWM. The effective result is visual flickering in some instances. Not as noticeable with a flashing insert lamp, but it is noticeable with lamps that turn on steady. The effect varies from machine to machine, and insert to insert. To deal with it, unfortunately, is more difficult than GI flicker. A simple rectifier isn't enough, as it's already DC power being applied. Nor can any hardware be added to the machine to eliminate it. It's all down to LED selection and trial and error. But if you do suffer from this problem, you need to step up to the more advanced LED's such as the Noflix Plus from Pinball Center EU or the ABlaze "Ghost Buster". Both of these designs feature capacitors that smooth out this type of flicker.
Constant-On	A very limited problem on some machines, generally this is seen on older solid state Williams pinball machines such as Flash, Gorgar and Firepower, in the flasher lamp circuits. These older flasher designs featured a warming circuit that constantly applied a low voltage to the flasher lamps. This was done to improve the response time of the flashers, while also helping the longevity of the bulbs themselves. To eliminate this issue, you need to disconnect that separate warming circuit under the playfield. You will see a small circuit board connected to the flasher lamps, with a pair of resistors on it. Simply remove the larger of the two resistors, and you're done. Now, you'll also see this problem with all the insert lamps on Atari pinball machines. In this case, you're out of luck. All the insert lamps in an Atari machine are also kept warm, but via the main lighting circuit via a PWM method. Nothing you can do about it.
Too-Fast	This is a subjective problem really, but for some people it's a valid complaint. Incandescent bulbs take a short amount of time for the filiment to warm up to the point of creating light, and when shut off they take another short time perioud to cool down and stop illuminating. LED's work on a totally different principle, and have a significantly faster response time both in turning on and turning off. The reality is that this difference in response time is responsible for almost all of the issues people have with LED's, as well as the compatibility problems dealt with on this page. The circuits and software were designed with the slower response of incandescent bulbs in mind. As many lights on a pinball machine are also designed to flash on and off, the faster response time of LED's can be very harsh at times. A great example is the rapid flashing of the entire machine, including all the GI and insert lamps, on Black Knight when starting multiball. The difference between the two lamp types is very easy to see in that case. I happen to like it, as it makes the effect more dramatic, but some people don't like the harshness. Again, it is subjective, but if you prefer the more smooth transition the main solution is in the choice of LED's. You'll need to step up to the mode advanced Noflix Plus or "Ghost Buster" LED's.
Loss of Dimming	More modern machines feature the ability to vary the brightness of the lamps. Williams WPC machines can do this on the GI circuit, while Capcom machines were able to do this on all the lamps in the game (so I'm told). However some LED's aren't capable of going along with this. I haven't investigated this issue enough yet to offer up a solution yet, as I don't know for sure via what method the dimming takes place. It all depends on if it's handled by PWM or by varying voltages. I'm told that the Noflix Plus and Ghost Busters are compatible with this feature, but I can neither confirm nor deny this. I would love more input.