Announce: Frosted “clear” Drop targets

About 3 months ago; we announced on Pinside that we entered into a distorbution agreement with Pinball.Center to begin carrying their Frosted Clear drop targets for modern Stern, retro Williams, and old school Data East Pinball machines.

You can use these Drop targets anywhere you want to backlight them with LEDs but they have much better resiliency than the 3D varieties which were available a couple of years ago. Unlike the 3D printed varieties; these are injection molded out of Polycarbonate (Lexan) in Germany for maximum resilience until man can mass produce Transparent Aluminum.

To answer the question of ultimate resiliency; we sent a set of these drop targets to @vid1900 on Pinside to put them thru some checks. He reports that after 2 months of heavy commercial use, and over 900 games none of the sample drops have been damaged. You can read more about his honest review on Pinside.

We currently offer three styles of these “clear” drop targets in our store:

Already in Vid1900’s thread, several customers have begun to show how these drop targets enhance normally dark areas of their pinball machines:
Fytr on Pinside outfitted his Iron Maiden with our Clear drops.
Stern Iron Maiden Pinball
See more on Pinside.
roar on Pinside outfitted his The Walking Dead with our Clear drops
Stern The Walking Dead Pinball
but he went the added route of installing the stock decals over the drops. See more of Roar’s work on Pinside.

As expected; these drop targets are available for immediate shipment in our webstore:
Pinball Drop Targets

Data East: Chase rope for Star Trek and Hook – Part 1

The Data East Chase rope lights used in two Data East Pinball machines (Star Trek: 25th) and Hook) are a huge problem on the game. So much so; that my Ebay-purchased game came with no rope lights at all. ūüôĀ This blog series walks thru my intention of recreating the chase rope lights – but made out of LEDs so they use less current, generate less heat, and can be used for decades without any issues.

First, some credit – Patofnaud on Pinside wrote a great tutorial on repairing these chase lights. I used this pinside thread almost exclusively for this blog series and if you happen to have the original rope lights; please take a look at his tutorial.

My game has no chase lights to repair; so I’m going to have to replicate the chase lights. I decided that I didn’t want to try and re-configure a standard off the shelf rope light because they likely don’t support doing a +12VDC common with three ground leads as discussed in Patofnaud’s post #1. Additionally; I don’t have exact specs of the rope light w/ regards to light spacing, diameter of the rope, ect. Since I’m going to have to recreate the lamps; I have decided to do a conversion to LEDs… specifically, using some “fairy light LEDs” which have recently become available on the market. I started by going to Hobby Lobby and buying a set of their battery operated lights using a 40% off coupon. Amazon has a whole bunch of alternate versions of this product… so you might be better off looking at Amazon if you don’t have a Hobby Lobby near you. B072NH2FQ1 seems to be a nearly identical match to what I got from Hobby Lobby.

These strings appear to be made of discreet 603 Warm White LEDs soldered to a common anode and common cathode. The LEDs are encased in a hot-glue like product to protect the LEDs from mechanical stress and help with water proofing. The fact that all LEDs are in parallel might end up being an issue because you can’t control the current into each LED. LEDs wired this way means that any variance in forward voltage drop (Vf) between the diodes in a series may mean that LEDs with low Vf would get more current that LEDs with higher Vf and could lead to premature failure of those leds. We’ll see long term if this becomes an issue with this project.

Taking apart the battery pack of the fairy LED light uncovered what I thought… A power switch and a 1/4W series current resistor of 15ohms. 3AA batteries supply 4.5V which is current limited by that 15ohm resistor. I did some quick measurements of the entire string and IIRC; the whole string took around 113mA with the 15ohm current limiter. I don’t recall what the series Vf was for the whole string.

Because the LEDs are powered with a 4.5V source; it becomes rather obvious that I can’t use these as a drop in for the 12V incandescent rope light originally in the machine. I’m going to need a conditioning circuit which will drop the 12V down to ~4.5V and provide some current limiting. I started by measuring my machine’s ramp to determine the approximate length of the chase lights. I measured with a piece of string to be about 15inches. The fairy LED lights have spacing of about 3inches which means that my largest segment would be about 15/3 = 6 leds, max. These 6 will become important for the series resistor calculations in the future.

Before I got to far into designing a voltage level shifter and current limiter; I looked at my machine. I couldn’t find the chase light connector shown in post #6 of pat’s thread. I couldn’t find it because the previous owner connected the left and right .156 connectors together with a Z-connector. That may mean there is now an issue with the chase light board (DE #520-5054-00 or #520-5054-01) in my backbox but I’m thinking connecting them together did no future damage since they are wired together in a OR configuration in the schematic manual. Meaning OUT1A is tied to OUT2A via the Orange/Black wire in the cabinet (See post #7, picture 1). I decided that Zconnector is a good place to put my Incandescent to LED converter circuit. My plan is to replace the Zconnector with a board which does the conditioning.

I decided I was going to abuse a LM1117 style +5V regulator to voltage shift the +12V common down to +5V common then use a series resistor to current limit for the LEDs. Since +12V is the common; I’d need to do a wired-OR configuration with a set of fast Recovery SCHOTTKY diodes to the OUT connections on the chase light board. I have no idea if the LM1117 vreg can operate properly with a v+ common connection; but I suspect it will have no issue given the frequency a which the lamps operate. Additionally, given the previous incandescent lamps had issues blowing the NPN Darlington arrays on the lamp chase board; I figured putting in a PTC resettable fuse would be a nice addition. My circuit took shape in eaglecad using Digikey as a part reference.

Here’s my original Fab A circuit, keeping in mind this is untested – but I retain all rights to this circuit for the moment:

Chase Light to LED
DE Chase LED conditioner

Some theory of operation:
D1&D2 provide some polarity protection – for paranoia. D3-D8 are the Schottky diodes which provide wired-OR back from the ground of the +5V regulator (U1) back to the chase light board’s OUT* connections.
C1, C2, C3 provide some filtering for the +5Vreg to help it maintain stability with the wired-OR configuration. D9 provides some additional protection for the Vreg – probably not needed; but extra insurance. R2 – R7 provide the series current-limiting resistors for the various LED strings. Why the different values of 13.3 vs 16.9? Well; my quick napkin calculations shows that there may be 5 or 6LEDs on the longest string and then one less on the shorter strings. I plan on connecting the longest string on the 1A & 1B lines while the shorter strings (with the higher resistors) will be on the others. F1-F6 are the resettable PTC fuses. The bidirectional LEDs at the bottom are monitoring the output of the chase light board to give me an indication the chase board is working properly. They will chase green if working properly. I basically created a small “Z-connector” board to condition these LEDs but also added some small connector boards to help me interface from the LED strings to a simple 4 pin 0.1″ pitch latchable connector. The idea is these smaller connector boards would be fixed to the end of the “rope lights” and allow for a quick connection.

A little background on the Series resistor calculations. Basically; Vf isn’t known for the parallel LED strings. You can’t measure Vf with the diode setting of a Digital volt meter which btw; my favorite is a Fluke 87 series meter. Vf according to my DVM is around 2.4V and we know that no current white leds operate at 2.4V for 20mA. Since I don’t know which LED the chinese put in these strips; I had to make an educated guess. To do this I went to and drilled down on warm white 603 LEDs, downloaded the table (using the button near the bottom of the page) and then imported the data into excel so I could get an average of the Voltage – Forward (Vf) (Typ) column. I calculated Vf ~= 3.23V. Armed with Vf, and the knowledge I wanted to operate the LEDs near their 20mA operational current so they would be their brightest I was able to calculate a theoretical series resistor. Here are the “knowns”:
Vf = 3.23.
Each LED should operate at ~18mA.
With the ground diode in the Vreg path… assume Vfdiode = 0.4V. This would cause Vout of Vreg to be 5+0.4V, or 5.4V.
“ground” will be thru the UL2003A darlington on the chase driver board. VCEsat = 0.9 min.
Assume 5 leds needed for longest string and solve using Ohms Law. R=V/I.
V = 5.4 – Vfled – VCEsat
I = 18mA * numOfLEDs in string or 18mA * 5
R = (5.4 – 3.23 – 0.9) / (5 * 18mA ) = 14.11 ohms
Subtract off typical Fuse resistance of 0.9ohms and you arrive at ~13.3ohms. Repeat the calculation for a 4 led string and you arrive at ~16.9ohms.

The only “gotcha” with this theoretical calculation is that what happens to the LED if we are drawing near 18mA? There’s no real ground plane or PCB to draw heat away from the LED. The only “heat sink” is the hot glue used to encase the LED and the wire LEDs connecting the LEDs. I’m hoping the low duty cycle of the LEDs will help keep thermal runaway in check. This is something I’ll have to watch in the final assembly. If LEDs start dying… we’ll know it’s either getting too hot… or the parallel LED VF vs current is a problem.

Here’s the Fab A boards as committed to OSHPark. This is their render of the boards as I don’t have them back from fabrication yet:

DE Chase Fab A (Top)
DE Chase Fab A (Top)
DE Chase Fab A (Bottom)
DE Chase Fab A (Bottom)

I’ll post more on the circuit boards in Part 2 when I get them back from OSH Park and have them built. We’ll see if my little experiment bears fruit.

Now onto the actual chase lights themselves. I thought about using polyurethane blue tubing from as I posted in Pat’s Pinside thread on post #19. But honestly, I don’t really feel like the blue rope light fits the ST:25th theme very well. To me; it looks like some attention getting feature to draw in the eyes of a would be quarter-dropper in an Arcade. Not that is a bad thing; I just figure since I’m not going to an have original rope light assembly with the proper Light spacing… I might as well try to make it fit the theme a little better. If not blue, then what? Well Clear is definitely an option… but it won’t really hide the led wiring very well. I had a lot of extra 1/2″OD, 1/4″ID rigid Acrylic tubing left over from the guide plastics from Star Trek: The Mirror Universe custom pinball project. I was thinking of doing that with some custom Acrylic etches on the tubing. The problem is that failed due to piss-poor-Management so I can’t really go there to use their rotary attachment on the Tortec. My new-to-me Epilog Laser doesn’t have a rotary Attachment, yet. Not sure what I’m going to do about that yet… Even if I get a Rotary… what would I put on the Tubing? Then there’s the issue of bending it properly… which shouldn’t be too hard given the Youtube videos for Hard Tubing in water cooled case tutorials.

Then I stumbled across ENT Corp on Ebay who seems to have colored versions of this rigid tubing available in cut-to-order. I went ahead and ordered 6 pieces of the smoke acrylic tubing custom cut to 15.25inches. After I experiment with the etching and try my hand at the clear tube bending… I’ll proably finalize the chase lights using the smoke tubing on the final machine.

That’s it for Part 1 of this blog series… I’ll start Part 2 when I get some tubing experiments done and/or when I get the PCBs back from OSHPark. For now, Peace and Long life…

Announce: Star Rollover LED boards

We are pleased to make a delayed announcement of a product which we’ve had in stock for almost a year. This Star Rollover LED board fits on the underside of your Playfield under a Star rollover assembly and will bathe the Star Insert is lower power LED light. With this product you can replace the inefficient horizontal lamp socket and incandescent light bulb with this board:
Star Rollover
Each board provides 4 natural white LEDs in a non-polarized light from either a 6.3V source. Because the board has a built-in rectifier bridge; you can supply power from both a 6.3VAC GI circuit or ~6.3VDC controlled insert. You can even control the brightness via a microcontroller PWM signal or from one of the new DIY control systems such as the PROC or its PD-LED driver board.

The design also features a brightness resistor at R5 to allow you to dial the brightness to your desired level. A hole in the center of our PCB allows the actuator to work from the insert to a standard Leaf switch typically under the insert.

A typical installation may require a set of #6-32 x 0.25 inch wood screws so you can bolt it to the back of the playfield under the star rollover insert. Electrical installation is super simple; simply solder the GI connection from the old horizontal lamp socket to the JGI connection, or jump to the nearest GI socket as we did in our machine below. Here is an example installation we did on our Star Trek: The Mirror Universe custom pinball machine.

Source: My Star Trek: The Mirror Universe custom machine

This populated PCB is available for immediate shipping in Our Online store @

Announce: Stern Star Trek Nebula Mod

We are pleased to announce the official launch and immediate availability of our Nebula Backbox lighting kit for the Stern Star Trek Pinball Machines. While the product has been available on our site for almost a month; we just completed our detailed step-by-step instructions to aid you in installing it in any Stern Star Trek Pinball machine – enabling us to make the product official with this announcement.

This kit comes with a set of three Printed circuit Board Assemblies (PBAs) which you snap apart and install behind the stock nebula plastics on a Pro, Premium, or Limited Edition pinball machine’s Back board. Like our Kelvin product; it is 100% compatible with the PWM circuitry on our GI Dimmer so the customer can dim or control the Nebula lighting for both Normal and Klingon MultiBall modes.

This kit is a Do-It-Yourself mod requiring assembly using the attached step-by-step instructions:
Stern Star Trek: Nebula Backboard Upgrade
and may take a couple of hours to complete.

Here’s the stock, unlit Nebula backboard on the Author’s machine:

Here’s the Nebula backboard with our DIY Nebula kit installed:
New Star Trek Nebula mod

For More information; please visit our online store’s product page for more detail and an order link:

Stern Star Trek: Warp Ramp LED Mod

One of the items that somewhat bugged me about my new Stern Star Trek LE Pinball machine, was the LED in the warp ramp popup insignia. Specifically; I always thought the two SMD red LED didn’t quite fit where it was placed in the machine.

Photo Credit: Kawydud@Pinside
Original LED in Popup. Photo Credit: Kawydud@Pinside

The plan was to “replace” the LED round lens with a laser cut lense which duplicated the artwork on the insignia’s plastic. To this I disassembled the plastic by removing the four screws… and took the plastic to my HP scanner where I scanned the art into my computer. Then using Corel Draw, I traced the Red Arrow from the plastic art:

Portions (c)2013 Stern Pinball
Scanned Plastic with New Arrow Art

I recreated the arrow using red; then added the black border around the plastic to block light and give a round area to mount the new LED. Once I had the recreated arrow; I broke it into two laser cut pieces. One would be cut out of the matte/diffused Red acrylic which was used on the Stern Star Trek Pop Undercaps. The second would be cut out of 1/8″ opaque black acrylic – this piece serving as an outline for the red piece and support from the LED.

I took these files to where I laser cut several of each piece for experimentation later at home. Once the laser cutting was complete; I used the black cad files to laser etch some 1/4″ plywood to act as an assembling aid/surface. When I got home; I used the plywood and some wooden toothpicks to clamp the two pieces together:

Acrylic Clamping
Acrylic Pieces Clamped for Bonding

With the pieces together; I used some acrylic bonding solvent to glue the two pieces together. I let the acrylic bond overnight.

The next afternoon; My Comet Pinball Red LEDs had not come in the mail – so I decided to go ahead and use the original LED for experimentation. I cut the round lens off the original LED using a new XACTO knife and then using some two part 5minute epoxy; I glued the lamp to the new lense:

LED Clamping
LED Clamped to new LENS w/ 5minute Epoxy

I allowed the epoxy to cure for about an hour. I then reinstalled the plastics and the new LED assembly:

LED Clamping
Warp Arrow LED Installed

I’m really quite happy with the way this turned out. It defiantly spruces up the warp assembly.

Star Trek: The Next Generation Klingon Bird of Prey Mod

I recently purchased a
1994 Hallmark Star Trek Klingon Bird of Prey
from a fellow Pinsider. This Ornament came ready to install into my 1996 Williams Star Trek: The Next Generation Pinball machine. However before I installed it in the machine; I wanted to make further modifications to the item. My previous installation had installed a die-cast

2005 Corgi Klingon Bird of Prey

for which I’d followed the recommended installation of putting the incandescent light bulbs under the ship:

Before – incandescent light bulb sockets- ICK!

Immediately upon this installation; I knew it wouldn’t do… but I waited several years until I got one of the hallmark ship mods. I decided back then that I was going to put some Electroluminescent panels under the wings… but then came to my senses that the EL panels loose their brightness rather quickly. So; after getting the Star Trek: Mirror Universe pinball machine to a Phase1 complete state; I returned my attention to this mod. I decided this time that I was going to use superbright surface mount LEDs to replace the light bulbs and their bulky sockets.

I started by researching the type of LEDs. A Digikey search came up with some super brights; relatively cheap but with a lot of light output. I figured I could fit about three of these LEDs under each wing; so I began the design phase of the project. I started by doing a pencil rub of the wing’s paint job. This gave me an approximate size of the PCB I needed under the wing. I scanned this pencil rub into the computer and vectorized it into a PCB using the technique posted here. With the PCB outline created; I proceeded to create the schematic of the LED board. I made a design choice to rectify the 6.3VAC GI power rail so that polarity wouldn’t matter during install. I also decided that I’d use a BJT current mirror to light the first LED and drive 20mA thru it. Then use the second leg of the current mirror to drive the remaining two LEDs. To ensure stable voltages/currents; I put a 3.3V LDO regulator and some caps on the first leg to try and keep the brightness from flickering with the 120Hz FWB power rail.

I have decided to release the schematics to the public under the TAPR Non-Commercial Open Hardware License which indicates:

You may make products based upon this design, provided you do not make more than ten units in any twelve month period for your personal use.

If you agree with the license terms the resultant schematic is posted here under TAPR/NCL license:

STNG KBOP LED schematic
STNG KBOP LED schematic

You can buy the bare PCBs from OSHPark from here. Total cost to build this board in single unit quantities as of 6/15/2014 was $14.55 / a pair of boards.

The entire project package is here: STNG_KBOP TAPR Package
It contains the schematic, NCL license, Bill of Materials.

This project requires SMT soldering skills so be prepared. I used a syringe with solder paste to populate the PCBs then used a skillet to reflow the solder. Here’s the assembled PCBs:

Then I assembled tested the circuit first with my 5V bench supply; then with a 6.3VAC transformer from RadioShack:

With the boards tested; I began refitting the Hallmark KBOP mod which looked like this:

I removed the green heatshrink hiding the LED wing guns and cut the red & black wires as I had recreated the wires in the PCB and had embedded the resistors hidden under the black heatshrink near the guns:

Originally and in the PCB file; I had decided that I wanted to use 2 qty #0 self taping screws to hold the PCBs in place. These were speced at McMaster Carr as #94209a005; but I didn’t want to pay for S&H for that single box of 50. Instead I drilled out the holes a little larger and used #2-56 @ 3/16 of a length. I carefully marked drilled the wings of the KBOP and taped them with my #2-56 tap set. You MUST be careful here not to drill through the wings. Here’s the PCBs mounted:

I then proceeded to solder the cut GI wires for the wing guns to the Jin connections on the PCB. I also connected the Guns to the JWing connection at the edge of the PCBs with a short piece of red rework wire after removing the inline resistors at the LEDs. I secured the electrical connections at the gun LEDs with some liquid black electrical tape:

I then proceeded to attach the GI connection from my machine along with the bracket. Reusing the older wireing harness as desoldered from the bulb socket assembly made sure the under wing LEDs lit in the same was as the bulbs:

With that the modification of this mod is complete. Here are some mandatory money shots to encourage you to do the same to your machine:

Overall I’m very happy with the results; the Red LEDs really light up the Playfield and I do not have to look at those light bulbs any more. The only thing I noticed with this mod is that my machine doesn’t seem to give me enough voltage at the GI connector to fully lite the two LEDs on the second leg of the current mirror. I think this is because the STNG controls GI; which means there is an extra silcon device between the 6.3VAC transformer and the GI lamps. This is evident when running the shuttle craft missions when all the PF lights are of in this video mode. In a future revision of this mod; I might try directly hooking the second leg of the current mirror straight to the GI input (not FWB rectified) to see if I could coach more voltage across these two LEDs in series.

This PCB obviously fits the 1994 Hallmark ornament seen here and it also seems to fit the Corgi 2005 Klingon Bird of Prey also used in modding these machines.

Enjoy Modding!

Star Trek HAPP CoinDoor Red Alert Indicator

On my Sega Star Trek Captain’s Chair restoration; I had to install a HAPP Coin Door¬†because I’ve been unable to¬†locate an original door. This Restoration is featured at¬†¬†or for those that are interested in the complete project. Anyway, while installing my custom Coin Door inserts; I decided I wanted to modify the stock HAPP coin “guides”. The stock guides look to be black ABS and well … just don’t do it for me. The stock guides are shown here:

you can see the tiny little square just above the coin slot. This is the area we are going to target with this modification. Once you take apart the coin door; you’ll see guide is a piece of formed black abs:

Once I had this guide out; I measured it using a pair of Digital Calipers and layed it out in Corel Draw X4:

The “nubs” would be laser cut out of 1/8″ Red transparent Acrylic and the blanks would be cut out of black opaque acrylic.

The top of the red “nub” was sandblasted to give it a frosted looks so it’d defuse the light as it exits the nub. When assembled the new guide looks like this:

A 1206 Red LED was soldered into the red acrylic’s pocket with red rework wire attached to the anode and black to the cathode.

I need to drill the coin chute to¬†route the LED’s wires:

and I route the wires out the top side of the chute:

Now that I have the LEDs wired in… what am I going to use them for? Well; I decided I wanted to run the LEDs simular to the¬†Series’ Red Alert indictors I viewed a couple of youtube videos and did some wiki searches; but couldn’t find a “factoid” which gave me the timing of a TOS Red Alert indicator. Therefore; I just decided to make timing which would be pleasing to my eye. If anyone knows for sure a flash target; let me know or leave comment and I’ll figure out the correct timing circuit to flash at that rate.

Anyway; I decided to go with a somewhat simple 555 timer circuit. I have decided to release this  design under to the public under the TAPR Non-Commercial Open Hardware License which indicates:

You may make products based upon this design, provided you do not make more than ten units in any twelve month period for your personal use.

The 555 timer operates in Astable mode governed by R1,R2, and C1.

Schematics :

Click to view Red Alert Indicator Schematics in PDF

¬†The current implementation of the circuit has an “on” time of ~2.6 seconds and an off time of ~1/3 of a second. There is a RC timer made up of R3 and C2 which allows the LED to “wink” into it’s on state. LEDs D1 and D2 are driven by the 2N3904 transistor and wink on at the same time… Rather than do a current mirror; I decided to let D2’s current ~= D1s current given the transistor’s common-base current gain… IE alpha = beta/(beta+1)¬† which¬†@ ~20mA the 3904’s beta is a minimum of ~90… so alpha is .989 the current of D1. The circuit uses the RST pin of the 555Timer to add additional stability by putting a reset delay on the flipflop in the 555 at ~5seconds. Overkill; proably – but should be very reliable.

The current in the LEDs is controlled by R9 a series resistor intending to limit the current. It was emperically derived using SPICE as a starting point… and then the circuit breadboarded to maximize to 18mA of current flow. D4 is a schottky diode to protect the 555 from reverse wiring mistakes. The LEDs were left unprotected because they and the¬†BJT¬†are diodes … so shouldn’t be impacted by reverse wiring mistakes; additionally, the LEDs voltage drop is already ~2V.. so¬†the 0.1-0.3V voltage drop of D4¬†might effect brightness.

The PCB is designed as a two layer PCB with through-hole parts on the top layer to enable those less skilled with a soldering iron to build the circuit.

Red Alert LED Fab B Top Layer w/ Silkscreen

Red Alert LED Bottom w/ Silkscreen

For those without PCB layout tools; a bare PCB is available from the batchpcb service for under $11. You can purchase the boards from this link:

The Bill Of Materials (BOM) of the board is available from Digikey for under $6 (as of the time of this post). A CSV file with the digikey part numbers is here:

Here’s a package of the materials above as a single download:

Here is the the prototype assembled:

Next I needed to mount the PCB inside the coindoor. Since this is a modern replacement HAPP door; I decided to drill and put some #6-32 hex standoffs inside the door. I taped the holes and also added some epoxy to keep the standoffs in place:

I mounted the PCB:

The rework wire is self adhesive; which made it easy to route the led wires back to the PCB and secure it to the reverse-side of the coindoor.

Last but not least; I connected the power to the +5V circuit at the base of the 555 lamp on the coindoor. the lamp circuit on the Sega Star Trek is tied to the +5V PSU… it isn’t 6.3VAC like Pinball Machines.

Here’s the circuit installed and running:

Want to see it in action? Check out our YouTube video: