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REVIEW: Pinitech’s Retrofit Conversion LED Display Kit


The games produced by Bally and Stern between the years of 1977 and 1984 were enormously popular with players when they first graced the arcades, and remain popular to this day. Given the sheer number of games originally produced during the 1977 to 1984 run by Bally and Stern, the survival rate is very high and there is a great demand for reproduction parts to keep these games running properly.  This is the second review in a continuing series where Credit Dot will examine some of the reproduction parts being manufactured, and how technological innovation is making Bally/Stern games look and play better than ever.


If you are a collector of Bally /Stern games from the 80s, chances are you’ve encountered some displays with “bad glass”, wherein the digits or segments of the digits inside the glass tube no longer function properly. Perhaps a portion of the digit won’t fully light up. Perhaps it won’t light at all. Such issues could be attributed to bad components on the display’s circuit board, but if you are suffering from bad glass/out-gassing, you’ll know it. Short of finding replacement glass, it renders the entire display, including its accompanying circuit board, useless. More often than not, you’d need to track down a single working display, or just give in and replace the whole set with an LED aftermarket solution costing upwards of $200USD.

Collect enough Bally/Stern games and you’re bound to end up with a handful of non-functioning displays with burnt out glass. Now, thanks to Pinitech’s Retrofit Conversion LED Display Kit, you can use these out-gassed displays to manufacture a set of fully functioning, lower-voltage LED displays. The Retrofit kit contains a new display circuit board and LED digits to replace the glass tube, and a variety of electrical components that need to be substituted for components on the original Bally/Stern circuit board. This kit is a DIY solution, and does require some skill at soldering and de-soldering circuit board components.

If you haven’t already figured it out, this isn’t a solution for everyone. First, you need to have a set of out-gassed donor displays on hand.  A novice collector probably won’t have an entire set kicking around, so there would be the extra expense (and bother) of finding and buying a set of dead displays to use in conjunction with the Retrofit kit. And second, you’re going to need the time, skill and proper tools to perform the conversion. Those looking for a plug and play solution need to look elsewhere. There are plenty of aftermarket plug and play options available (both Rottendog and XPin have 6- and 7-digit display sets available). For those looking to recycle their electronic waste and don’t mind getting their hands dirty performing the conversion, the Retrofit results in a great looking display at a price that can’t be beat.

The Retrofit Conversion LED Display Kit was originally introduced about a year ago by Pinitech, LLC. The project was rolled out for beta testing in late-July 2016, followed by a general release a month or so later. Wayne Eggert is the proprietor of Pinitech, and the rise of his company as an aftermarket pinball solution brand is best described in his own words:

“Pinitech has been around since 2014. I started selling NVram using generic boards back in 2012, but began doing custom boards in 2013 for a more professional look. After learning the ropes some with PCB design, I moved on to creating some diagnostic tools I wanted for my own personal use. I funded the projects by selling extra boards that I had created. Through 2016, I’ve mostly just offered diagnostic tools and NVram, but I’m now branching out into other products like the Bally/Stern Retrofit Conversion Kits.”

Not only does Pinitech help the pinball community by offering products designed to keep our games running efficiently, Mr. Eggert is also a Pinside mainstay, posting as “acebathound”, and can frequently be found patrolling the tech help threads, offering solutions and suggestions to collectors with malfunctioning machines.


Pinitech offers three base display colours in both 6- and 7-digit Retrofit kits—blue, white and amber. The latter closely resembles the original colour of the Bally/Stern displays, while the white can be used in conjunction with about a dozen colour filter options to customize the display to your tastes. The pricing for one kit, for a standard game with four score displays and one credit display, as of July 2017, is as follows:

  • 6-Digit Displays in BLUE – $89.95USD/set
  • 7-Digit Displays in BLUE – $94.95USD/set
  • 6-Digit Displays in AMBER – $84.95USD/set
  • 7-Digit Displays in AMBER – $89.95USD/set
  • 6-Digit Displays in WHITE (includes 1 colour filter) – $94.95USD/set
  • 7-Digit Displays in WHITE (includes 1 colour filter) – $99.95USD/set

The contents of a 7-Digit Retrofit LED Display Kit

For those games with an odd-number of displays, like Six Million Dollar Man with six score displays or Elektra with an extra bonus units display, Pinitech will sell individual display kits to supplement the above complete packages. As you can see from the pricing structure, using the existing display PCB from an out-gassed display, and building the kit on your own results in quite the savings compared to other options on the market.

Other display options check in at about twice the price. Rottendog offers 6- and 7-digit amber display sets, which come fully assembled and are plug and play, and are $199USD, while XPin’s sells their amber displays individually, also plug and play, and are $54.95USD each (that’s $274.75USD for an entire set). Wolffpac Technologies offers a similar DIY display kit, requiring no donor display, and will set you back $144.95USD for a 6-digit amber set that you will have to assemble yourself.

If you have a set of dead displays lying around, the Retrofit solution is a no-brainer. Not only is it the most affordable option on the market, you can customize the colour of the displays to suit your game without breaking the bank. A colour upgrade isn’t available for the Rottendog set.  You’ll pay $20USD more per display (or, $100 more per set) to get the XPin colour option, which ships with red, green and blue gels to add colour to the base white display.


The displays come with a set of detailed instructions–and it is my opinion, that even the most novice of PCB tinkerers won’t have a problem making the conversion. The first thing I did when setting into the conversion process is to remove pin #1 on the header pins of each individual displays. This step is so important, it is mentioned about a dozen times throughout the written instructions. Pin #1 sends high voltage to the display, which is no longer needed with the low voltage LED conversion. I didn’t chance cutting the pin off, I de-soldered the pin and pulled it out completely on the entire set of displays before I even began.

You have a couple of ways of replacing some of the PCB components for the conversion: removing them completely and installing the new component, or installing them in parallel, which will basically piggyback the new component onto the old component on the solder side of the board.  I would recommend the former of the two options, as it gives the project a much cleaner look overall and allows less margin for error.  I used a Hakko 808 desoldering tool (now being sold as the Hakko FR-300 Desoldering Tool) to completely remove old components from the board, and then soldered in the new with a temperature controlled soldering iron.  The de-soldering tool isn’t a must, but it nearly guarantees a clean pull of all the old solder, freeing up the old components and preventing the chance of pulling or breaking traces.  You’ll be removing more than sixty points of solder for just one display, so having a de-soldering tool in your toolbox is a sound $200USD investment if you don’t have one already.  In total, for each board, you are replacing 7 or 8 transistors, and four sets of 6, 7 or 8 resistors, depending on if the display is six- or seven-digits.  I was methodical in my approach, and removed one set of resistors from my board, and installed the new components before moving onto another set.  Otherwise, I thought it would get pretty confusing keeping track of a bunch of empty resistor holes and following the Pinitech cheat sheet of what goes where.  The placement of the resistors on the board is somewhat logical, but in some cases, like in any PCB board design, the component is placed where it fits to minimize space, and not where it should logically be placed.

To make things even more interesting, Bally and Stern had many revisions of the display board throughout the ten year run of their classic games, so depending on which version of display you have, the parts that need to be replaced will be in different positions on the board.  The community has accounted for this, and the Pinside thread dedicated to the Retrofit displays has identified the majority of the different board revisions, giving the DIY-er a visual cheat sheet to identify which components need to be replaced.

The points of contact for the old glass need to be removed from the component board completely, or need to be cut close to the old glass so the old metal tab connectors can be affixed to the new upright display board. To the new upright display board that will replace the glass, you’ll need to attach the LED digits, which have eight contact points per digit that need to be soldered.

Once the two boards are affixed together using the provided brackets, you can solder the metal tab connectors to the display board or use the new angle connectors provided if your original tabs were manged or missing.  The angle connectors provide a cleaner look overall, but it requires a bit more effort to install. To finish up, you’ll need to choose a way to jumper the 5V line to the high voltage line. Again there are a number of ways to do this, but each involves a jumper wire from one point of contact to another on the solder side of the display PCB. This step is the only time in the whole process that the conversion would appear to be “hackish”.  None of the points of contact are near each other, so the user will just have to pick one that they think looks the least invasive.

The instructions outline how to test the display on the bench using a 5V power supply, or, if you are feeling brave, and have triple checked your work, you can install it into your machine and watch the cool lights of the LED display its segmented numbers.  If for some reason segments don’t light, the guide will help you troubleshoot the problem.  I had two digits that refused to light on one display, which ended up being a couple of bad digit drivers.  Luckily, Pinitech has accounted for these bad components (they are ones that are not replaced in the conversion) and includes a small number of extra 2N5401 transistors as backup.


I was one of the beta testers for the Retrofit kit when it was first introduced, and since that time, I’ve known Mr. Eggert from Pinitech to be helpful and very personable when it came to his products and the hobby in general.  I thought I would give him a forum here to explain the nuances of the project in his own words.  The questions I posed to him appear in bold below:

Credit Dot: When did you first discover that the Retrofit kit would be something that could be successful in the market?

Wayne Eggert: “I created a Pinside thread to judge interest on the idea and decided that I’d use the thread to seal the fate of the project.  There was a reasonable amount of interest right off the bat, especially considering it was such a niche project.  The excitement in that thread was indication that at least a dozen or two of the conversion kits would sell.”

CD: How long did the research and development portion of the Retrofit project take?

WE: “R&D was most of the first quarter of 2016 and then another couple of months later in the year.  A couple of weeks alone were dedicated to figuring out how to do load testing and to get a baseline for what to expect for current usage with and without LED displays on Classic Bally/Stern machines.  A prototype was cooked up and the next major step was figuring out if there was a way to create an efficient conversion design. If that couldn’t happen, there was no reason to pursue the project further.”

CD: The circuit boards attached to the display glass on the original Bally/Stern displays came to market with many different designs over the years.  Was there difficulty accounting for all of the different configurations of boards out there?

WE: “Definitely.  Working within the parameters of the old boards made it a huge challenge–and part of that was due to quite a few different display revisions over the years.  Whatever I came up with had to work with all the revisions.  Not only that, but it had to allow people to mix-and-match displays of various revisions without any noticeable differences in brightness or functionality.  Many hours were spent gathering schematics and actual display boards for each revision, and many more looking at everything as a whole and creating a conversion circuit that would work for all of them.”

CD: What unique elements of the original Bally/Stern design allowed the conversion to be possible?

WE: “Since the old display driver circuits used many resistors and transistors, it made it easy to swap those components out for different values.  For instance, if I couldn’t swap transistors for mosfets, the 4543 would have been over-driven on its outputs.  Had the drivers been dedicated ICs unique to plasma displays, the conversion may not have been possible at all.

There were quite a few things along the way that could have derailed the project completely.  I could easily list over a dozen snags I hit in the design, but somehow for every one of those snags I was able to find a solution.  Even just the screw hole locations for the plasma glass display bracket on the component board couldn’t have worked out any better.  The new LED display panel had to sit at pretty much an exact location and I lucked out and found a right angle 90 degree threaded bracket that worked.  Too far forward and it would have caused the digits to hit the backglass, too far back and there would have been clearance issues with the digit drivers on 7-digit Bally displays.  It amazed me that the entire project went this way.  There was lots of nail-biting and thoughts of canceling the project, but in the end, a solution for everything materialized.  Maybe that happens when you REALLY want a solution, and you find a way get there!”

CD: The converted displays tap into the 5V power supply, bypassing the high voltage needed to power the original displays.  Do the converted Retrofit displays tax the 5V line in any manner significant enough to impede the machine’s performance?

WE: “I definitely didn’t want to create something that would cause a lot of extra load to be added to the 5v regulator.  If I couldn’t get the conversion displays to match the efficiency of a normal aftermarket LED display set, there was no sense in doing them.  I’m proud to say the conversion displays match or beat efficiency of most of the other LED displays on the market.  Not bad for old-school technology!”

CD: What advantages does the Retrofit kit offer over the other aftermarket display systems available on the market?

WE: “The single largest draw is price-point.  But I think the idea of using existing boards is also a major advantage.  Lots of people had old boards sitting around “for parts” that were collecting dust.  This is a way to turn them into something useful again, gain space, save money and create some great looking LED displays!  At the time, these conversion kits were also the only budget way of getting WHITE LED displays that could be used with color filters for unlimited color choices–at about one-third the cost of the other option on the market.

There are other advantages that people see once they assemble a set.  The displays look professional.  Everything lines up nicely and everything from the instructions, to the PCB design, to the circuits themselves, were looked at in detail and has professional polish.  I’ve been told by several people that the aesthetics are better than anything else on the market.  It’s cool hearing that, considering people are comparing these conversion kits to plug-and-play aftermarket displays.”

Many of the products on your site are available in DIY form, where the end user assembles the product themselves. Have you seen an increase in hobbyists wanting DIY kits?  As the hobby grows, are you seeing the skill set of the common hobbyist mature?

“I think the interest is growing in DIY kits.  It’ll never be on-par with plug-and-play, but having kits available like this with clear instructions that allow someone to assemble without frustration the first time helps grow the demand for DIY options.  When things are frustrating or unclear it becomes a major deterrent. These conversion kits are definitely on the more difficult end of DIY, but even so, I tried to make them as user-friendly as possible.

Pinball these days is an expensive hobby and DIY is a way to save a few bucks.  Pair that with the accomplishment you feel successfully building something.  It’s built into us, especially guys, I think–we like to build.  But the advantages are far greater: the skills learned in a Pinitech DIY project are transferable to other aspects of the hobby.  Improved soldering techniques, desoldering techniques, troubleshooting–it all helps create confidence and knowledge that could come in handy down the road.”

Your main pinball interest seems to lie in the early solid-state games of Bally and Stern.  The majority of your products at Pinitech cater to that era.  Does your interest in pinball span all eras of machines?  What are some of your favorite Bally/Stern titles?

“Funny you say that.  I often think about how anyone that is checking out products I sell, at least up until this point, is definitely going to think I’m only into Classic Bally/Stern machines.  I actually enjoy most games from the early 80’s to present day releases.  Anything with better sound and more complicated rule sets, than the very early solid state games, I enjoy.  I’m definitely a big fan of Data East, Williams System 11 & WPC.  I’ve done more with diagnostic tools for Bally/Stern because I started out with those machines early-on in the hobby.  They’ve always been more affordable, and there’s a lot of neat titles and artwork in that era of games.  They’re very approachable from an electronics standpoint, too.

Two of my current favorites for Bally titles are Xenon and Mr. & Mrs. Pac-Man.  I think it’s mostly nostalgia that does it for me on Mr. & Mrs. Pac-Man, but it helps it’s also a later Bally with more going on and better sound.  I’m itching to get LED displays installed in that machine.  It’s been sitting folded up for five years and I think it’ll look really cool with blue, red or yellow displays.  Or maybe a mix of all three colors!”


I’ve performed the conversion on two sets of displays with dead glass–a six-digit conversion for a Stern Stars and a seven-digit conversion for a Stern Star Gazer. If focused, and I kept to the task, I could have one display converted in about thirty minutes.  Overall, I am very happy with how the displays look in the games.  The numbers are nice and robust, and are crisp and bright without being blinding and looking out of place.  I went with blue displays for both Stars and Star Gazer–they were the most affordable, and fit the overall colour scheme of both titles.  The Stars came with four dead displays out of the five, while the Star Gazer came with no displays at all, but I was able to find someone to sell me a set of dead 7-digit displays for $20.  Would I convert a set of displays for the sake of converting to low-voltage LED if the displays worked properly?  Absolutely not, but it is a nice option to have when a set of displays with bad glass presents itself. The final product is robust and professional looking, especially considering it is a DIY project that uses original parts from the 1980s. This project is extremely affordable, compared to the other options on the market, and further, it feels good to take something that would otherwise be junk and put it back into service.




Pinitech – Classic Bally/Stern Conversion LED Display Kit
Pinitech – Retrofit Photo Gallery
Pinside – RETROFIT Classic Bally/Stern DIY Plasma-to-LED Conversion Display Kits