For early Bally SS games you need a new driver board. Alltek makes a very nice one that most folks use. Either that or you need to solder components on each and every lamp socket.

http://ksarcade.net/driver-boards-1/alltek-systems-lamp-driver.html

This board also eliminates the 'flicker' issue and so you can just use the cheaper Pinballife or CointTaker LED's without worry.

I had leds in my evel knievel. you don't need a special board.

The issue is not with ghosting or the inherent flicker in an LED. Rather, on Bally's, the controlling transistors (SCRs--silicon controlled rectifiers specificially) they used require a specific amount of current running in order to stay latched (on). If the current (amp) draw falls below a threshold, the scr turns off, then turns back on, causing a very noticeable and random flicker of the LED.

There are multiple fixes:
1) Use a big enough LED array within a single lamp that causes enough current to be pulled. You'll find that most cheap LED's draw 10 to 20 ma vs the 150 to 250 ma of a #47/#44 incandescent. If you find a LED lamp that has multiple sub-leds that increase amp draw they won't cause the SCR to unlatch. However the side effect will be extra cost and way too bright for the insert, so not doable for most.

2) Cause additional current to be pulled without creating light (or heat) to the level the SCR needs at a minimum. This is as simple as soldering a single, 470 ohm resistor across every single switched lamp socket underneath. A resistor costs 1 to 5 cents each in bulk depending on your source, and just need time to solder. This fix simply 'sinks' some of the power from the +5.9V lamp line to ground through the SCR at the socket making it appear more current than the LED uses is being drawn when the SCR is on. The nice thing is this doesn't prevent you from using an incandescent lamp as the resistance is higher than the lamp, so electricity will follow the least resistance--the lamp. The only bad thing about this is you have about 60 sockets to solder 2 wires to and makes it 'non original'.

3) Buy a new $100+ board that uses newer transistors to not require such high current draw.

I am working on an alternate solution costing much much less than a $100 board or soldering 120+ wires underneath the playfield. I have a prototype completed, tested and working, and am considering offering something up if there is enough interest. It would be completely plug-n-play and not require removal/replacement of any board or soldering or underplayfield access. The cost to fab the boards would be significant so would need to judge demand before I take the plunge LMK if anyone is interested, and I may consider this this summer.

BTW--This only affect switched lamps. GI / Backglass lamps are not affected because they either use mechanical relays in some cases or there are enough lamps on a single SCR to maintain enough current.

Luke, your game would be unplayable to me. The LEDs flicker very bad in a Bally game.

I didn't think it was that much worse than the flicker I already had with the regular bulbs.

^ this is for controlled lamps only
I just solder chip resistors across the LEDs themselves - keeps the game original to easily go back to incandescent bulbs. If you don't have the soldering skills to do this then you will have to solder the resistor across the sockets. Never had a problem with ghosting or flicker.

If you have flicker on the GI in old Ballys this is totally different, this is the GI AC supply from the transformer that causes this. I think the "No-Flix" brand bulbs might help this.

I would be quite interested. Probably 7+ boards depending on cost.

You don't have to remove the resistor to go back to normal incandescent. The lamps work fine with it still in place as they have lower resistance than the resistor.

Yep, as I stated at the bottom of my message

-----------

Wow.. Okay, 7 sets (each game would require 3x mini boards to interface with the connectors/harness) of boards would probably cover my first PCB fab run. I haven't priced things out, but a friend who does a lot of fab-ing for some battery charger projects thought there would be no problem in doing this for about $30 for a set of boards (PCB fab, installed components soldered in, testing). Is that within a reasonable range -- $30 per game?

Also, want to add explicitly (I touched on it above) -- Ghosting is NOT an issue with the old Bally's. Since a separate wire from a separate transistor is sent to each lamp socket with a common wire across the other side, there is no 'matrix' of rows/columns to deal with, so turning on other lamps cannot cause another lamp to have a phantom/ghost light.

Therefore once you solve the current draw limit of the old SCRs (for switched/controlled ones), and then optionally attack the overall GI issues with their power supply design causing other flicker, you can apply any LED to the game without having to pay more for non-ghosting/etc...

GI is not an issue. There is more than enough amp draw on a chain of 10 LEDs controlled by a single SCR on a PF GI or backbox GI circuit... that pulls 2.5A if #44 incandescent normally which equals or .20A if they are 20ma LED's. At most any flickering that ever is noticed there is caused by the overall design of the power supply that on some machines drops the voltage to the GI when solenoids are firing/etc..

When you start witching to programmed/controlled/switched ones where there is one LED per SCR is when you will see the random flickering; and badly so. Since .250 A of a #44 is a lot more than a .02 A of a single LED for the latch to sense.

Yep, count me in also.

The installation will take under 1 minute by anyone who at least knows how to change a fuse No soldering, no cutting, 100% removable in under a minute as well. Compatible with both incandescent and LED (can mix them together, don't have to remove to still use incandescent).

I have a prototype (non PCB based for now) working, and am pricing out a small test sample size PCB fab so I could get a couple made and send out for someone to test after I verify on my Bally. (As it took about 4 hours to wire strip, cut, crimp, solder all the components for the prototype set :(so I'm not going to hand make these!)

If all goes well with a sample and beta test, then I could then do a large run and make them available. ETA is this summer. Right now I'm trying to figure out the best design (board layout) both in terms of quick assembly on my side, and quick and solid installation on a game, plus optimizing size for highest yield as PCB fab is pretty spendy.

Thanks for the interest! The more stating interest, the higher I will prioritize completing this over trying to get my Bally acquisition fully working

If you are interested, send me (or post here) a list of machines you would consider putting it in, and if possible, a picture of the back side of the backbox lamp boards on them (showing any aux driver board positions) so that I can verify a couple of assumptions about positions of those boards. Thanks!

"Is that within a reasonable range -- $30 per game? "

Yes, would buy it right now for Future Spa.

It will be a set of 3 mini boards with circuitry that will interface between the connectors and the wire harness off the lamp board, along with another much smaller board to interface with the square Aux Driver board elsewhere to pick up an additional signal. (I'm making an assumption that every backbox has at least one AS-2518-68 Aux. Driver GI Flasher or an AS-2518-82 Aux Driver TRIAC Lamp flasher mounted behind the backbox sockets---if that is not the case, then I need to look for alternatives (or require a single solder connection by the user)). I need to spend time flipping through some manuals or pictures but not a lot show the back side of the backbox lamp board so I can see where they are positioned.

Once I get the actual boards fab'd, I will post a video of the installation and results (with and without them installed). Given current interest, I will try to get these fab'd in the next 6 weeks.

I haven't had a chance to pull out the board from Future Spa to take a pic of it, but I will get around to it and send you a link!

I have 7 Bally machines of this era, from Strikes and Spares through Centaur. Do all of them have this issue and will this board set address the issue in all of them? I was hoping to convert them all eventually to LEDs.

Do other manufacturers from this era have the same issue? For example, I also have a Gottlieb Devils Dare and Williams Pharaoh and Solar Fire. Will they take LEDs fine or would they exhibit a similar issue?

Ultimately, I would take one of these for each applicable machine (up to 10).

i convert my bally playboy because i wanted pink leds.

alltek board will fix this problem.
if you put leds in g.i in early ss, no problem but if it's a control lamp, you need the board.

game look amazing with leds.

I haven't had a chance to pull out the board from Future Spa to take a pic of it, but I will get around to it and send you a link!

I am not looking for pictures of a particular board. I'm looking for a picture of the back side of the hinged wood panel that holds all of the backbox lighting. I'm trying to determine where the little 2"x2" AUX DRIVERS (not Aux Lamp Drivers--a different thing) are located on various ones. Attached is a sample of the type of picture I'm looking for.

I have 7 Bally machines of this era, from Strikes and Spares through Centaur. Do all of them have this issue and will this board set address the issue in all of them? I was hoping to convert them all eventually to LEDs.

As long as they are late 70's / early 80's Bally (or Stern) Solid State systems using the AS-2518-23 / AS-2518-14 or STERN LDA-100 lamp driver boards utilizing SCR's of type MCR-106 and 2N5060 / 2N5064, then they will exhibit this problem.

Ultimately, I would take one of these for each applicable machine (up to 10).

Awesome! Looks like I have enough requests, even if only 50% follow through, to make this a go. Finalizing layout, and then need to pick the right fab and get some of the adaptor boards produced. Thanks for everyone's interest!

BackSideOfBackboxLampBoard.jpg

I think this is the specific list of games that use the lamp driver boards:

Ali, Big Game, Black Pyramid, Centaur, Centaur II, Cheetah, Cosmic Princess, Dolly Parton, Dracula, Eight Ball, Eight Ball Deluxe, Elektra, Embryon, Fathom, Fireball Classic, Fireball II, Flash Gordon, Flight 2000, Future Spa, Galaxy, Gold Ball, Harlem Globetrotters On Tour, Hot Hand, Iron Maiden, Kings of Steel, KISS, Lectronamo, Lost World, Magic, Mata Hari, Medusa, Memory Lane, Meteor, Mr. & Mrs. Pac-Man, Night Rider, Nine Ball, Nitro Ground Shaker, Nugent, Orbitor 1, Paragon, Pinball, Bally Playboy, Power Play, Quicksilver, Rolling Stones, Silverball Mania, Six Million Dollar Man, Space Invaders, Speakeasy, Spectrum, Spy Hunter, Star Gazer, Star Trek, Stars, Stingray, Strikes and Spares, Vector, Viking, Viper, X's & O's, Xenon

Oh, okay, gotcha. I'll have to look...I don't remember seeing those boards.

This thread is exactly what I've been looking for. I've been working on putting LEDs in my Bally Star Trek. Backbox and GI have been no problem and work fine. It's the controlled lighting in the inserts that I had the flickering problem. I read somewhere else that a 1K resistor across the socket will work so I dug through my box of resistors and found a 470 ohm, a 1.8K, a 3.3K which all worked and stopped the flickering. Also tried a 9.1K and a 22K but they did not work. I guess they had too much resistance.

I've been trying to figure out how and why using a resistor across the socket would work and this thread finally answered my question. Now I understand what's going on with the circuitry on the lamp driver board. Thanks for the explanation!

I've now gone ahead and ordered 100 1K resistors off of ebay. Set me back an entire $1.49 including shipping! Once I get them I'll fire up the old soldering iron and get to work. It will also give me a chance to fix a few of the loose sockets that have been bugging me too.

What I don't get is why the guys like Cointaker don't offer a bulb with the resistor already built in? They offer non ghosting bulbs that have some type of circuit built into the bulb. What is it that they put into a non ghosting bulb anyway? It would seem really easy to put a resistor into an LED and would make it real easy on those that don't feel comfortable in soldering or adding another board to their pin. It would be a great new money maker for the LED sellers also.

Thanks!

I have a few old Bally and Stern games that I plan to convert to LED over the next year or so and would be interested in buying atleast one set to try and if it works, I will probably buy enough to cover all of my early Bally/Stern pins. Thanks!

Bally Mata Hari
Bally X's & O's
Bally Centaur II
Bally Space Invaders
Stern Star Gazer
Stern Pinball

-- Shawn

Thanks for the information. I wondered myself, at what level the SCR actually needed to stay latched. I hadn't gotten around to trying multiple sizes, since 470K was the semi-standard published by enthusiasts.

If you're willing to wait a few months, my kit will hopefully be done and save you all that soldering under the playfield But yeah, that the cheapest (money) but most expensive (labor) fix for it.

Because that would be extra power draw across the socket and would negate some of the benefits of LEDing in many games -- slightly increasing heat; etc. -- not useful if the game doesn't have the problem to begin with. It would be an extra cost to assemble each bulb as well to address only a small subset of Bally/Stern games from the late 70's/early 80's (as compared to where most of their income comes from -- Mid 80's to now. Plus; as with the non-ghosting ones, there are a very limited sub-set of lamps that use them, limiting your choices.

A capacitor is used to require a certain level of power to flow in to charge it up before it allows it to go onward to the bulb. Ghost voltages will slightly charge the capacitor but not allow the LED to light. If you've got a EE and CS background, here's a site that details the ghosting problem on later pins: http://emmytech.com/arcade/led_ghost_busting/index.html

Awesome!

Short update: Between work, and acquiring another pin / things have slowed a bit on the project but I still am looking at summer to get the boards fabed and tested. The only small roadblock I've hit is that I have found that not all backboxes' light panels have a AUX DRIVER attached to them. That was a key point to providing a power signal without requiring the buyer to do any soldering. With the cost of wire (and neatness), I'm not looking forward to having someone run it all the way under the PF to a random location either. I'm going through some schems and pics to see what is 'common' across all the Bally games to see where I can make a single plug-though connector to gather the signal I need making it fully plug and play in all circumstances.

I replaced the lamp driver board in my Xenon with the Altek board (either had to repair or replace it in any case) and it made a bit difference, recommend it. I am going to replace the board in my Centaur at some stage, tried a couple of LED's under the playfield and oh boy, the flicker would have caused an epilectic to fit!

Yes your board looks very promising! But for less than $1 I don't mind doing the labor. That's half the fun owning these pins anyway! Plus I will also be doing the same to my Game Plan "Star Trip" cocktail table pin. It has the same problem as the Bally's as it also uses a similar circuit in the lamp driver board. The resistor fixes the problem for those units also.

Do you know what type of resistance a standard 47 or 44 bulb has? I would figure you would want to use just the right amount of resistance to keep that SCR latched other wise you would just be wasting more energy than needed. I guess the 1K should be just fine although the 3K seemed to work also.

Any thoughts? Thanks!

Well I finished the LED job in My Bally "Star Trek" and I just would like to share how I installed the resistors on the sockets. First we all know that the Bally lamp holders are pretty bad. They get loose after time and start to go intermittent. To fix them you need to solder the socket to the bracket and solder the wire to the "nub". Also to make the LEDs work without flickering you need to solder a 1K resistor across the terminals of the socket. So I decided to kill 2 birds with one stone. Look at how I soldered in the resistor to the lamp socket:

// Error: Image 118977 not found //

As you can see I soldered the socket to the bracket at the edge where they meet. I also used this as one point to solder one end of the resistor. The other end of the resistor I soldered directly to the socket "nib" AND also the tab where the wire is soldered to. This creates a solid conection between the "nib", wire, and the other end of the resistor. Lamps are all now very solid and the LEDs work perfectly with no flicker!

That's basically what my boards will do. However it is not a 1 minute mod. It took me 3 hours to bend, wrap, cut and solder about 70 resistors across every terminal to the destination on a inline adaptor on each of the board on my prototype -- About the same time it would take to do it at each socket. (Dealing with .100 spacing and tiny SIP connector adaptor legs does take time to ensure no solder bridges are formed/etc.. -- definitely not the wide open space of soldering directly on the socket)

The final circuit will be on a PCB with SIP style resistor arrays that will be able to be soldered a lot quicker to make the product, and will work inline with the connectors. The problem is finding the common point to send all of the other ends of the resistors to without requiring end-user-soldering. In some games there are additional connectors nearby to hook into, others, it appears, from my looking at pictures and schems, it will require soldering. Perhaps I will just require that; and 1 connection soldered vs. up to 140 would be seen as a gain yet It still has the benefit of no 'damage' to any lamp socket or lamp driver board by soldering--especially by those that aren't that good and is 'instantly' removable in case you want to move it to another machine or something or need to replace the lamp driver board and not lose all that mod work.

I still am working on the project and hope to get the boards fab'd soon with more details later. Please hold out a little longer

I'm still game for one, that's for sure... I haven't replaced all my LEDs yet in Future Spa, but I have them in hand...will let you guys know how that goes lol.. still have the original driver board in my game.

Yes, you can put the resistors in at the board but, if you don't want to spend two evenings like I did soldering 50+ resistors then I would definitely consider Pac-Fan's board. Each lamp would need it's own resistor so you would still need to be soldering a lot of resistors either at the board or on the sockets. For me I needed to do solder work on most of my sockets anyways because most of them were loose and giving me problems. Soldering in the resistors at the same time was easy to do and solved two problems at the same time.

That is what the lamp driver board does in your pin. Yes it is one wire per bulb and the control circuits and connectors are all found on that lamp driver board. If you don't know what you're doing however, I wouldn't be messing with that lamp driver board! Just get Pac-Fans adapter board or spend the time to solder in the resistors at each socket. Lot easier and safer than messing with the lamp driver board.

Rufessor, Just noticed in your video that you have a buzzing sound in attract mod that changes with the changing of the display from hi score to last score. I had the same problem with my Bally "Star Trek" machine. Seems that it is a ground loop problem with the sound board as once I unscrewed the sound board mounting screws the buzz went away. Decided to isolate the sound board from the mounts by using a thin nylon washer as a spacer and also 8-32 nylon screws to mount the board. Solved the buzz problem. I'm an audio engineer and I'm very familiar with ground loop buzzes. You may want to try that and see if it works for you.

You keep referring to the "power supply board". Do you mean the Voltage Regulator/Solenoid Driver board or the power supply board located above the transformer? Neither of these boards are related to the work you would need to do on the lamp driver board regarding adding the resistors to stop the LED flickering. The mod cannot be done on either of those boards.

I assumed from this statement that you had really no experience in electronic circuitry. But then you make this statement:

This is very conflicting information. If you have no issue in rebuilding a board you should have the expertise to read schematics and understand what board does what. If you don't even have a clue where to look how can you go about rebuilding a circuit board successfully?

Moding the electronics of a circuit board is not an easy thing to do unless you now what you're doing and understand basic electronics. You said:

Soldering a resistor across the two contacts of the lamp socket is not putting it in series. It is putting it in parallel with the bulb. To do the same on the board you need to do what Pac-Fan has done. Make a resistor array that taps into each lamp's circuit on one end and connects them to a common point on the other. That's the problem that Pac-Fan is having with offering his board. It may be difficult to find a common point that is easily accessible and can be connected to without soldering. Also different games are set up differently so it can be difficult to find the correct common point. He wants to make it as easy as possible to use his board especially for those with no electronic skills.

Since you are doing a restore project on your playfield I don't see what the problem is adding the resistors to each lamp socket. If you may be removing all the sockets off the board anyways, it would be real easy to add the resistors at that point of time. Plus, as Pac-Fan mentioned, you can still revert back to incandescents at any time even with the resistors there. If you are trying to keep your game "original" any type of modification to the board would even be a worse thing to do. Best bet for you would be to go with Pac-Fan's board once he has them available. Looks like it would be an easy plug-n-play option with maybe just one solder connection needing to be done at the common point of the controlled lamps.

If I were to disassemble the wiring harness from the light control board, and add a resistor to the end of each independently controlled light (which must be a single unique wire- correct) and then simply solder a connector onto the other end of the resistor and plug it back into the harness...

That description is called wiring in series. That will not work to solve your problem. The LED may or may not light depending on the resistance and would do nothing to fix the flicker problem. You need to wire the resistor in parallel with the bulb to make it work. Look at my diagram below and it should clarify the difference immediately!

PS.jpg

This is not difficult at all - I modified a 19777 Bally Strikes and Spares in an evening with a soldering iron and a magnifying lamp. A few dollars in chip resistors, no special add on board. I modified the LEDs so to keep the game original and it WORKS PERFECTLY. The original reference doc is below:

"Once upon a time there was a led that flickered when it was installed
in an older Bally or Stern pinball machine. The LEDS flickered on any
machine that used a Bally As2518-14, AS2518-23, or Stern LDB-100. These
lamp driver modules were used from 1977 thru 1989. These boards use SCRs
to switch # 44 Lamps on and off in pinball machines. This has worked
well for many years, until someone tried to use a led instead of a #44
lamp. The LED flickered. I discovered that the reason the led flickered
was that the LED drew no current below it’s forward bias point that it
would not hold an scr latched. If a resistor is added in parallel with
the led, it would draw enough current to keep the scr latched and there
was no flicker. (Life is Good). Through testing I found that a 470 olhm
resistor was more than enough to keep any of the scrs that I tested
latched. The 470 olhm resistor can be added in the socket of the led,
soldered across the lamp socket, or soldered on the lamp driver module.
The electrons don’t know or care where the resistor lives, as long as it
will cause a 1ma load to the anode of the scr. All 3 ways have been done
and they all work well." - text by Ron Googe."

Yes you can do it as you pictured. But to do each bulb circuit it would be a lengthy process. As you said you would first have to figure out which wire from which harness is running each one of the controlled lamps. You then could remove that connector from the harness, cut of the wire, strip the wire, add one end of a resistor, crimp on a new connector and insert it pack into the harness. Once you have done that for each of about 30-50 lamp circuits you would then need to tie all the other ends of the resistors together and wire them to the common point which you would still have to find somewhere.

What you end up with is a very time consuming process that leaves you with a mass of resistors protruding from the wiring harness which would really look like a massive circuit board hack job! And, if you somehow made a mistake and connected a resistor to an incorrect wire, you risk damaging something else on the board.

In my opinion it is a lot easier to simply solder a resistor across each bulb socket. It takes less than 2 minutes to do per bulb, it's easy to locate the bulbs you need to do, there is lots of room to solder, once it's done you barely can even see the resistor is there on the socket and it looks like it supposed to be there just like the diodes and capacitors found on the switches and solenoids under the playfield. If you want to revert back to incandescents you don't have to do anything at all and if you really want to restore the machine back to original all you have to do is snip out each resistor off the socket. As a bonus the solder job on the sockets will probably improve their reliability especially on the cheap Bally sockets. Most important when you open the backbox it won't look like a massive hack job has been done to board.

Hope this info helps with your LED mod!

Yes, dealing with the LEDs themselves is a bit of a PITA. My eyesight is getting worse with age and spending an evening under a magnifier with chip resistors to solder them on the LEDs is a hassle. It was worth it though. Good luck.

Yes any of these 3 techniques will work.

What ever works for you is the best for you!! I would love to see pics when you get it done!

For me in my situation since I had to access each lamp socket anyways to install the LED I figured it would be the perfect time to also service each socket. Power down, remove the original bulb, clean socket with a "socket eraser", solder to fix bad socket design and also install resistor, install new LED, power up and check for proper operation. Each socket about 2-5 minutes depending on how hard the socket was to get to. Clean looking mod and very easy to do! The LEDs look great in my Bally Star Trek!