Earthshaker: Working on bad circuit boards

Let’s take a look inside the backbox of the game and see what we see…

Now that we’ve identified some issues with the aux power board, we have to deal with it, first by removing components…  Oh by the way… I’ve rightfully caught a lot of flack from the folks on rec.games.pinball about my “bridge rectifier removal technique”… Let me elaborate on that… Korn and others are 100% right in that it’s always bad to try and “force” any components from the board, and if solder is not properly melting, it’s best to re-flow new solder onto the old joint to help remove stuck pins.

I would like to say in my defense, this board was really messed up beforehand.  The traces and thru-holes were already damaged on the board, and I had carefully loosened most of the pins of the BR before turning on the camera, so it looks like I’m using more of a “gorilla” technique than in reality.  So that’s not a good example of the best way to remove components, but I knew already I was going to have to rebuild all those traces and I was a tad impatient.  My bad.

Now we begin work on the actual circuit board and show how to identify broken traces and find where they go so we can run jumpers. Looking at the schematics helps us double check everything.

Now putting the finishing touches on the jumpers and adding the bridge rectifiers…

Now comes the moment of truth, putting the repaired aux power board in the machine and turning on the power for the first time:

So far so good for my first major Sys11 repair.  While I have a few Sys11 games, I haven’t had to do a whole lot of repair work on them so this was a learning experience for me too.

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Fixing a dead dot matrix display board

The other day the DMD just went “poof” on one of my machines.  After doing a little research, and checking connections and things, I realized the DMD board died.  In this installment, I walk through the process of rebuilding the power supply-portion of a Bally/Williams WPC DMD board.  In part 1 I describe what I’m doing and introduce you to the tools I’m using.

 

Next up, let’s talk about using a meter to check circuit board traces as we go along..

Desoldering and replacing components.

Now the moment of truth!  One thing I want to add is pay very close attention to each item you are replacing on these boards.  Two diodes, capacitors or transistors may look alike, but have slightly different values or part #s.  The three power transistors and the diodes are not all the same.  You may have to bust out a magnifying glass to note the different in the markings on each part.  This should also be cross-referenced with the schematics and/or parts list from the game manual.

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Bram Stoker’s Dracula pinball: from cradle to grave and back again

For my inaugural post, I am adding this video playlist, which covers the process I went through after picking up a Bram Stoker’s Dracula pinball machine.

The idea behind this video series is not as some kind of slick “how-to”, because I’m basically filming “on-the-fly”. I’m not doing any editing; I’m not staging any scenes. I’m turning on the camera and filming and what-you-see-is-what-I-see. So basically you can follow along with me as I unload this machine and bring it back to life. I’m not claiming to be an expert on pinball repair and maintenance — the Internets are chock-full of “experts”. I’m just a guy who decided to film his experience so you can have a little amusement following along with me. Will I make mistakes? Definitely. Will this be informative? Who knows? But hopefully it will be worth your time. Let’s see…

As you will see from this series, a simple pinball acquisition turns into a major set of modifications…

How long is this series of videos?  Too long I’m sure.. shot in little segments, at current time, totaling 36 parts, it chronicles the trials and tribulations of what it takes to recondition an otherwise “fully-working” game.. ha ha

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