Testing LEDs in an old SS Bally

[Nedreud]

Never seen a vector with LEDs before. Give it a go!

Indeed I will! Or have! Admittedly I've just stuffed them in without any modifications, e.g., resistors, etc., so the fact that anything works at all on a machine this old is a miracle. I will in due course do proper tests... this was just half an hour during my lunch break.

Respect to Dave Mainwaring aka @alchy at http://www.pinball-led.co.uk/ for getting my order to me in just 1 day!

All the bulbs on Vector are #555 wedges. From left to right fitted in the 2x, 3x and 5x inserts are Concave, Superbright and Premium 2 in green:


Vector: LED Testing by staticboy, on Flickr

From left to right fitted in the 1, 2 and 3 THOUSANDS inserts are Concave, Superbright and Premium 2 in blue:


Vector: LED Testing by staticboy, on Flickr

From left to right fitted in the 5, 10 and 15 THOUSANDS inserts are Concave, Superbright and Premium 2 in yellow:


Vector: LED Testing by staticboy, on Flickr

Hard to take photos of flashing lights! But somehow I got the Concave and Superbright in green (2x and 3x) and the Superbright blue in the 2 THOUSAND:


Vector: LED Testing by staticboy, on Flickr


Warm White Frosted this time in the left slingshot and inlane/outlane guide:


Vector: LED Testing by staticboy, on Flickr

Under the front plastic is a Cool White Frosted and behind under the curved plastic a Blue Frosted. I'm not sure about either the warm or cool white, but do like the blue Frosted under that curved plastic. Vector has quite a lack of under-plastic GI so it would be great to add a load using LEDs without adding any extra strain on the power supply. In fact, as 1 incandescent is the same as at least a dozen LEDs the overall current draw will be lower even if I add 20-30 extra playfield GI lamps!


Vector: LED Testing by staticboy, on Flickr

And a couple of videos. Especially impressed with the Superbright in green on the 3x insert. Based on these very preliminary tests I prefer the Superbright over the Concave (not bright enough) and Premium 2.

 

[Pinballdoctor]

mmmmm....gonna give it a try someday.

I have tried to put some Leds inthere about a year ago and some scr's died.....RIP

 

[Nedreud]

You may have noticed in video #1 that blue inserts 1 and 3 weren't flashing at all and that 2 was a bit random. Well, this is the infamous "flicker" of old systems like Bally that use SCRs to switch the feature lamps. Basically, LEDs draw so little current compared to incandescent bulbs that it is insufficient to keep the SCR latched (an SCR is basically an electronic switch). The fix is quite simple: put a small resistor in parallel with the LED to provide an instant and constant minimum current drain (here's a really good write-up with technical details). Values between 470 Ohms and 1K Ohms would be about right.

So, here they are, 470 Ohm resistors soldered directly across the lamp holder tabs:


Vector: More LED Testing by staticboy, on Flickr

The result is perfectly stable flashing LEDS. This video has Concave, Superbright and Premium 2 in the blue 1, 2 and 3 inserts:

In this video I switch the Concave in the 1 THOUSAND insert to a Frosted blue as I didn't like the light spread:

At the moment I erring towards going with the Superbrights for under plastic GI and the Premium 2's for GI where you can clearly see the bulb. The Frosted just aren't bright enough for GI, they are easily outdone by standard bulbs. The Premium 2's look nice where you can see them due to the faceted covers but the Superbrights have a really even spread below plastics such as the slingshots.

Here's a top-down shot (extra dark filter) of a Premium 2. You can clearly see the twin LEDs:


Vector: More LED Testing by staticboy, on Flickr

And here's the same shot of a Superbright. These guys have a small round recess in which sit 3 tiny pin-point LEDs. They produce a very even and very bright light. Not as widely dispersed as a Frosted but much more effective under a plastic especially those with a reflective white underside:


Vector: More LED Testing by staticboy, on Flickr

 

[Nedreud]

I originally posted this is my Bally Vector Shop Log but I think it makes more sense to have it in this thread as the title is more relevant:

Nedreud, is there any ghosting? I.e. Dimly lit LED that shouldn't be on at all?

No ghosting. Certainly none that I can detect even using the video camera on macro. Ghosting is most commonly caused by a software "bug" in WPC systems coupled with shortcomings in the lamp driver matrix hardware. It's always been there but switching from incandescent to LED lighting just exacerbates the problem to the point it's noticeable too humans.

There is an excellent, if somewhat technically in-depth article, all about it here: http://emmytech.com/arcade/led_ghost_busting/

To the best of my knowledge and understanding of the Bally lamp driver circuit, ghosting shouldn't be an issue on systems of this era. The main problem is flicker caused by the SCRs not holding their latch after the control signal has been removed, but as detailed above this is easily cured with the simple resistor fix shown above.

I'm interested to have a look at LEDs such as "NoFlix" and "Ghost Busters" because they also contain a capacitor to minimise ripple in the supply but which can also give the LEDs a brief fade out rather than near instantaneous off mimicking incandescent behaviour. The LEDs from pinball-led.co.uk already contain the twin half-wave rectifiers and current limiting resistors which is how they can be plugged directly into AC GI with out modification. The surface mount component packed into the #555 base is impressive! I pulled one apart to see how it was done - will post a photo later.

 

[Nedreud]

I originally posted this is my Bally Vector Shop Log but I think it makes more sense to have it in this thread as the title is more relevant:

As promised! Stripdown destruction of LEDs! Actually, it's okay, there's a happy ending.

So, here's what's inside an orange Superbright #555 SMD Wedge. First up, using some small snips I nibbled the edge off around the top. Initially I tried prising the LED and its mounting base out of the casing but it seemed to be well stuck and/or glued. The contact wires are quite thin and each wraps around the bottom edge:

Here's the top showing the SMD (Surface Mount Device) LED. You can clearly see the 3 LEDs within the white circular lens area as small black dots:

Next I unbent the legs:

And slid the components out of the casing. So, you can see that the contacts on the outside of the case are actually the legs of the resistors inside:

So, what have we got inside? Five components altogether: two 43Ω 1/8W Carbon Film resistors (yellow = 4, orange = 3, black = 1x multiplier, gold = 5% tolerance), two SOT-23 A7 Dual Switching Diodes and on the top a 5050 Package Triple LED. The two diode packages act as a full-wave bridge-rectifier. This is how these LED-based lamps can be plugged into an AC (Alternating Current) source such as the playfield GI. If they're connected to a DC voltage, such as feature lamps, inserts, etc., only one half of the rectifier is used.

As I don't know the exact specification of the LED I'll use some figures I found for a similar device: a Forward Voltage of 2.3V and a Maximum Continuous Current of 50mA. On a supply voltage of 5.9VAC in my Vector gives an ideal current limiting resistance value of 72Ω, so the two 43Ω resistors in series either side are about right (they're over-limiting a little and probably giving the LED about 43mA but this value has to cover a range of supply voltages, e.g., my Paragon kicks out 7.3VAC for the GI and many games use 6.3VAC).

And just to show I have not killed the LED taking it apart, here it it running of 6VDC. Aftwards I poked the legs back through the case and bent them back around to reform the terminals.

Next I shall be experimenting with some smoothing capacitors...

 

[Nedreud]

Found this image in my Dropbox showing how the four diodes are arranged to form the bridge rectifier which does the full-wave rectification of AC.



On the left is a graph of the GI supply which is commonly around 6-8 Volts AC. Because LEDs only work in one direction what happens is the LED only lights during the positive (green) part of the cycle. When the voltage is reversed (red) the LED doesn't light up. In the UK the AC is at a frequency of 50 Hz (Hertz) so the ON-OFF repeats 50 times a second. This can cause noticeable constant flicker, particularly when you catch the lights out the side of your vision.

What the bridge rectifier does is to "flip" the negative (red) part of the cycle over in the opposite direction (the graph on the right) so that there are now 100 ON (green) cycles per second and all of them will turn on the LED because they're all flowing in the right direction. The LED is still switching on and off very rapidly but at 100 times a second with a very short gap in between it's pretty much unnoticeable. There are solutions to this very minor problem, one of which is to add a small capacitor across the LED. Brands such as "NoFlix" do this. This stores a little charge during the ON cycle and releases it during the dips, thus smoothing out the "ripple". That is, it makes the rectified AC more like a true constant DC supply (more on that in another post).

All of this flicker has nothing to do with the Bally Lamp Driver problem that is solved by adding resistors across each lamp socket (see my 2nd post above). That is a separate issue to do with the electronics not being designed to drive LEDs.

 

[replicas]

Well that's as clear as mud.

 

[kevlar]

Nice post Nedreud, keep it coming.

 

[Chip]

You should add some of the Super-Flux bulbs available from Comet to the comparison. I just tried them in my Bally Playboy on the controlled lights in the backbox and saw no flickering like the CT mini supers. I'd like to see how they stack up against some of the others you have tested.

 

[Nedreud]

Hi @Chip, welcome to PinballInfo! I'd love to try some other LEDs for comparison. Mainly I was just experimenting with the technicalities of putting LEDs in old solid-state Ballys and seeing what would look good without being too harsh. Modern games look stunning with ultra-bright LEDs because it's expected and they're designed for it, but they look out of place on games from the 70s and 80s. That said, I think a futuristic title like VECTOR will suit LEDs well, but they mustn't be too over the top.

I had a look at the http://www.cometpinball.com/ site. Oh my... over-whelmed by choice! I'll see if any suppliers have them here in the UK because ordering from the US would cost me £20 ($30) for just 10 of those Super-Flux!

 

[kevlar]

I've bought from comet 5 times now and the postage isnt that much. I think its $14 for orders under $100 or something like that. I just made a large order and it was only $18.

Regarding the flux leds, they are nice but have a very long decay time so can look like they are ghosting at first, they arent, they are just taking a few seconds to fully fade out.

 

[Nedreud]

Hi @kevlar. The postage was $14 but at this stage I only want a few to experiment with, hence it being quite pricey and then inevitably getting hit with import duty and the Post Office's £9 "administration and handling fee". I don't suppose you'd have one or two spares I could try? Happy to pay for postage and their return if you don't want to part with any spares permanently.

I'm quite interested in modifying LEDs to have a "warm up" and "cool down" fading action to mimic how incandescent bulbs behave. I understand that some of these fancier LEDs have this behaviour built-in (it's just a capacitor and resistor) but a fade-out of "a few seconds" seems a bit excessive to me.

 

[Paul]

It's only an r-c network as you know... change the values (Mostly capacitance) and that changes the fade times...

 

[kevlar]

I'm definitely tempting fate here ( as I'm waiting for my 5th order to arrive ) but I haven't been caught for import duty ( yet! ) on my previous 4 orders. He always sends with value $20 on the box and with no receipt inside giving away the value of the order. I'm sure they will catch up with me eventually though, hopefully not this time.

I don't have any spare sorry, I've only bought a few of them and they are in machines. Pretty sure they are the same as the superflux sold by pinballcenter.eu.

 

[Nedreud]

No worries @kevlar. Good to know about ordering from Comet though.

Others know that curiosity will get the better of me and I'll be testing my own resistor/capacitor combinations soon enough!

 

[Poibug]

I think LEDS are great,when not uber IN YOUR FACE bright.They can be great for reducing heat/power usage on games where they are used.
sometmes less is more.

In lieu of how amny I have in stock,always less as always seem to need a few more

 

[Sam C]

I think LEDS are great,when not uber IN YOUR FACE bright.They can be great for reducing heat/power usage on games where they are used.
sometmes less is more.

In lieu of how amny I have in stock,always less as always seem to need a few more

I agree, you do get some purists "OMG YOU PUT LED'S IN YOUR GAME, HERESY!" who think anything other than a regular bulb is the end of the world. I tend to LED games for a number of reasons, anything sys 11 up it makes it look fantastic, something like F-14 or BK2K where it is fast and furious it only adds to the attraction of the game. Also the obvious benefits of the longer life span, sharper look and you are not putting as much stress on the boards (I think it is 17 LED's take the same power as 1 regular bulb?) giving them a longer lifespan.

However older games they don't tend to look right, stuff like EM's I would never consider doing it unless they could make an LED that emulates the look of a 44/49 etc. I think the warmer 'glow' of a bulb fits these better and just overall is better looking.

 

[Nedreud]

It's all so very subjective, and each to their own, but I agree with your general approach. LEDs anywhere in an EM probably wouldn't look right, but could be convenient for maybe the odd difficult to replace lamp. Incandescents might last only 1,000 hours whereas LEDs are good for 50,000 hours.

Modern games definitely look bling with LEDs. Could you imagine the latest Stern STAR TREK without LEDs? It's an epileptic's nightmare but By Golly! that game just hypnotises you into playing it! It's like having flash bulbs stapled to your retinas and wiring them up to the National Grid! And then there's the latest computer-controlled colour-changing RGB LEDs. Watching WOZ or the recent unveiling video for THE BIG LEBOWSKI is like some kind of freaky acid trip as the colours pulse up and down. TRIPPY

I guess it's those machines in the mid-70s/80s and maybe early 90s era that probably divide opinion most. I think my '79 PARAGON won't look right with LEDs. Certainly not in the GI. The colours just won't look right unless bathed in the warm glow of incandescents. I'll try some LEDs in the playfield inserts, they might work but only standard brightness, nothing too extreme. VECTOR however, with it's futuristic theme, definitely lends itself well to LEDs. I'll likely do a 100% conversion when I've decided which LEDs are the right ones for each location.

 

[kevlar]

I love LEDs and the oldest machine I've put them in so far is BK2K but this week I popped to Dave Wilcox's house for some parts. He has LED'd his Bally Atlantis with his 4 SMD superbrights and it looks FANTASTIC! I couldn't believe how good it looked, no ghosting either which is a major bugbear of mine. The only thing is he had to restrict LED's in the GI, it was too strobey.

 

[Poibug]

I keep thinking I have enough LED's then run out.
Main reason I tend to use them is less heat/power,tho I do love the effect of colour changers.
Plus,hyperthetically longer life with them.
Makes it better on hard to get at spots

 

[Nedreud]

Been a while but I started tinkering with LEDs again, this time to work out how to replicate an incandescent style fade on and off.

Because of they way they work LEDs effectively switch on and off instantly. Incandescent filament bulbs work by getting white hot which has an inherent warm up and cool down period. This may only be fractions of a second but the human eye can tell the difference. The difference is particularly noticeable on a pinball playfield where there is a series of inserts that are strobed to create a chaser effect. With LEDs the lit insert appears to "jump" from spot to spot whereas the fade-in/fade-out of incandescents appears to make the pattern "flow" or "glide" along.

So, how to make LEDs fade in and out? Quite simple actually. Just need a capacitor and resistor. At switch on the capacitor is an easier path so charge flows that way instead of the LED. As the capacitor nears full charge the current starts to flow via the LED and it fades on. At switch off the capacitor discharges via the resistor back through the LED providing a fade out. Changing the value of the capacitor and resistor change the fade in and out times.

Here's prototype number 1:



The problem here is that the RC network needs to be between the diodes in the #555 wedge base and the LED, hence this mess. Also the 220uF is about the right value but this is an old 25V one so it's huge. Resistor is a bit big at 220 Ohms but all I had to hand.

But it works a treat! Fade in time is probably 1/10th of a second and fade out maybe 1/2 a second. It looks very convincing next the incandescents. Will grab a video later to show it in action.

 

[Mfresh]

I've put LEDs under the inserts of my EM and it really makes it come to life, though I agree for GI incandescent looks better..

 

[J.C.Rox]

@Sounduser you may find the above thread interesting....

 

[Sounduser]

@Sounduser you may find the above thread interesting....

Yeah. Had a qwik look. Will read later.

 

[andy]

Been a while but I started tinkering with LEDs again, this time to work out how to replicate an incandescent style fade on and off.

Because of they way they work LEDs effectively switch on and off instantly. Incandescent filament bulbs work by getting white hot which has an inherent warm up and cool down period. This may only be fractions of a second but the human eye can tell the difference. The difference is particularly noticeable on a pinball playfield where there is a series of inserts that are strobed to create a chaser effect. With LEDs the lit insert appears to "jump" from spot to spot whereas the fade-in/fade-out of incandescents appears to make the pattern "flow" or "glide" along.

So, how to make LEDs fade in and out? Quite simple actually. Just need a capacitor and resistor. At switch on the capacitor is an easier path so charge flows that way instead of the LED. As the capacitor nears full charge the current starts to flow via the LED and it fades on. At switch off the capacitor discharges via the resistor back through the LED providing a fade out. Changing the value of the capacitor and resistor change the fade in and out times.

Here's prototype number 1:

View attachment 19750

The problem here is that the RC network needs to be between the diodes in the #555 wedge base and the LED, hence this mess. Also the 220uF is about the right value but this is an old 25V one so it's huge. Resistor is a bit big at 220 Ohms but all I had to hand.

But it works a treat! Fade in time is probably 1/10th of a second and fade out maybe 1/2 a second. It looks very convincing next the incandescents. Will grab a video later to show it in action.

But if the idea is to make them look like incandescent lamps.......can't you just actually use incandescent lamps?

Or am I missing something?

 

[Nedreud]

But if the idea is to make them look like incandescent lamps.......can't you just actually use incandescent lamps?

Or am I missing something?

There's a couple of things at play here. First, for me, is idle curiosity! It's just the sort of problem I like solving. Other reasons are more practical though: LEDs use considerably less power, around a tenth, so much less strain on the power supply. And they last longer. A lot longer. Typical lifespan for an incandescent is 1,000 hours but for an LED 50,000 it's about 50,000 hours!

There is of course the issue of aesthetics. So far I haven't seen an LED that looks as nice as an incandescent, either physically or in terms of the light it produces. Incandescent bulbs look nice even when switched off! You can often see the playfield GI bulbs and I think the glass capsules sparkle nicely with the warm (literally!) glow of light from the filament. They look pretty in themselves. I think this is mostly important for the GI. Cold, harsh LEDs do not look good illuminating a classic-era pinball machine. But for inserts I think it's less important. You can't see the bulbs so if the light that's produced by an LED behaves in fashion that is very close to an incandescent then I'd prefer to convert the switched illumination.

 

[Nedreud]

Started converting the playfield inserts on my VECTOR to LEDs. Going to fit the #555 Concave Insert LEDs I got from pinball-led.co.uk today. Going to take quite a while to do. Started with the 11 blue V-BONUS inserts near the flippers. I have to solder a 470 ohm resistor across every lamp holder which is rather slow going.

After I finished I discovered that the eleventh 20K bonus isn't working. Started lamp test mode and swapped bulb but still out and then the 20K in the upper bonus strip is out. Suspect I've got a couple of dead transistors!

 

[Sounduser]

Just out of interest. How much do the play field lamps draw?

 

[Nedreud]

Got busy with my GOLD BALL today and actually finished modifying all the playfield switched illumination, i.e., inserts, for LEDs. This was much easier than VECTOR because all but 12 lamps are PCB mounted instead of individual lamp holders. It was very quick to solder a 470 ohm resister across each lamp on the two PCBs which include from the flippers up: all the green bonus inserts, shoot again, specials, 2X, 3X, 60,000, 100,000, 200,000, G-O-L-D-B-A-L-L and orange arrows. The rest were individual lamp holders: 2 x rollovers, P-L-A-Y, 1-2-3, extra ball, special and 50,000 all up at the top of the playfield.

Overall I'm very pleased, especially considering these are the basic 29p LEDs. Green and red are excellent, orange and white are good. Only slight disappointment is yellow which is very weak. I ended up putting a white in the big 3X insert but didn't have enough to do the 1-2-3 inserts up at the top-right by the spot targets.

See what you think. Here's everything in test mode:

Thanks to @alchy for getting them to me in a timely fashion and with bonus 10% discount for forum members

 

[kevlar]

Looks great, can't wait to play it at the Expo