Welcome to the Pop-Bumper mod section of my Creature from the Black Lagoon Page!

For this section, I wanted to design my own version of the mod crated by Korn. You can see the original version here.

In Korn's version, he used 555 lamps in his approach. He mentions the fact that there is only about 1/8 of an inch clearance between the pop-bumper caps and the ramp. This is an important point because if I use the standard 555 lamp, (especially those that are cheap and fail often), I would have to remove the ramps just to replace the bulbs. To alleviate this problem, I decided to use LEDs in place of the 555 lamps. Here is how I designed my project. Thanks to Vince (Korn), for creating this novel approach to modifying the pop pumpers.

 

First, I had to find an appropriate LED that would not just shine upward but had a wide dispersal. I also wanted an LED that used the 555 style socket. I thought about grinding the tops of normal super-brite LEDs down but that seemed like a lot of work. I searched the web and at superbrightleds.com, I was able to find just what I needed. Here is the address to buy the LEDs. I chose the blue version of the LEDs due to my wife commenting that blue flashes inside teal pop bumper caps would look great. :)

Click the picture below to use as a guide to help you find the LED on the above website.

Once a suitable LED was found, I needed to determine the correct resistance value to protect the LED from too much current. Since these LEDs will be connected directly to the pop bumpers, and the fact that they are $3.75 each, they will need to be protected!

I planned on connecting the LEDs to the pop bumpers because I enjoy the flash effect one gets when the pinball hits the pop bumpers. Due to my lack of engineering knowledge, I could not calculate reliably, the value of resistance I needed. Thus, I created a test-rig to help me.

The test-rig allowed me to test the pop bumpers with the LED in-circuit, without destroying the LED. The in-line potentiometer allowed me to set the resistance to 1000ohms (maximum value of that pot), to start with. This allowed the LED to flash, but its output was weak. I gradually changed the resistance value of the pot downward to gain a brighter flash. Eventually, I found the resistance value that was not enough to protect the LED and it died. From this value, I chose the next closest resistor I had in stock and that was 680ohms. I used a 1/2 watt resistor to ensure it could handle the heat if needed.

These LEDs are rugged and designed to be used in automobiles. They require 12 volts to function which is well suited to my application because the pop bumpers are high voltage. These LEDs are not capable of using the 40+ volts of a pop bumper, but are designed for a higher voltage than normal .7 volt LEDs and therefore, I don't need as much resistance to protect them.

Click the pictures below to see a close-up view of the materials I used for the test rig and the completed unit.

   
            Test rig parts                                    Test rig assembled

Click the picture below to see a small clip of the initial test I ran with the help of my wife  and the test rig.

After the tests were over, and I knew the parts I needed, I next had to determined how to put it all together. I wanted to have a nice looking setup and one that could be reversed if a future owner did not want to have the mod in place.

I decided, after going to Radio Shack, that I would use barrier strips. I found some interesting ones that had a mounting hole and the strips were vertical. Since the pop bumpers do not have lamps, I ordered some replacement 555 sockets from Pinball Life. I also decided that to make things nice and neat, I would use spade connectors wherever possible to aid in quick-disconnects. Click on the pictures below to get a closer look at the materials used.

 

I sat down and drew out this diagram to help me connect all parts together. In the diagram, the voltage would go from the coil, through the lamp, over to the barrier-strip, through the resistor, and back to the coil to complete the circuit. Click the picture below to see a close-up view of the mod.

Using the barrier strips, I was able to incorporate the 680 ohm resistor into the same part. I soldered the resistor between two of the terminals on the barrier strip. Using the spade connectors, I soldered them to the end of jumper wires. I was able to use spade connectors on the barrier strip and all other connections, (coil lugs) were soldered. Please refer to the diagram above to see all connections.

Click on the pictures below to see the parts I used, resistors soldered onto the barrier strips, and spade connectors soldered onto the wires.


   Spade connectors on lamp wires               Coil jumper wires                        Materials from Radio Shack

 
   Barrier strips with resistors soldered    Barrier strips with wires connected        Soldering spades to wires

I wired in the LED and did a test fit and thankfully, there was room!

As I said, I wanted this to be neat and look semi-stock. Therefore, I mounted the mini-boards
under the playfield. Here are some pics showing the boards being mounted and wired in.


Overview of barrier strip connection      Red for coil, black for lamps            Staples used to hold down wires



Two barrier strips can be seen here    Shot of all three boards installed        Close-up of connected board

Once that turned out ok, I was good to go on installing the other LEDs.

We are getting to the point where we attempt a live test! I went into test mode
and fired up the pop-bumper tests. Click on the movie reel to see the first tests.

Now we're getting somewhere!! I decided to try the test with the new
teal pop-bumper caps installed. Click the movie-reel below for that test.

That looks great! I took some pictures of the teal caps installed.

Here we are at the final test, in-game play! Click on the Creature to view!

Well, that does it for my write-up on how I did my pop-bumper mods. I am sure
they could have been done easier, and most likely messier, but I did what I thought
would look good, still be able to reverse, and not cause me problems in the future.

 

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