Tie And Jeans

Easy Can Take A While

Today was a good day for Makers and pinball.  On our pinball TODO list, there was a single-line item – “Replace flipper coil.”   Here’s a bucket of photos and a little anecdote about the unexpected complications that emerge when you grapple with real/authentic problems.

This is the underside of a pinball flipper.  This one is in good shape. Replacing a good coil should involve about 6 screws.

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This one caught on fire at some point.  Fire is bad for pinball. When our replacement coil arrived, two students volunteered to remove the burned one from the machine.  “Hey, maybe we can do a better job than the last guy when we solder it back in place!”

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Removing a flipper coil shouldn’t require you to remove the mounting bracket.  But when this coil burned it fused to metal plunger (seen here sticking out to the left with a tiny scrap of fiber board).   Attempts to dislodge the plunger did some significant damage to the front bracket, so we decided to remove the whole shebang.

Naturally, the metal plungers are one of the few really unique parts in this machine. Despite the fire damage, that metal cylinder has to come out.  After several minutes with a hammer and bit, students decide that our brute force isn’t going to overcome the power of FIRE.  What to do?

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“Coils are just spools of wire, right?”  Well, they’re dense spools of wire.  400 winds of 29 gauge and 375 winds of 21 gauge.  Every single loop of it fused and fried at the same spot.

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Which leaves us with the melted remains of the plastic coil sleeve, fused to plunger and enlarged by the coating of magnet wire.  Even after the students picked at the base with needle nose pliers, it wasn’t going to slide free of the mounting bracket.

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Snipping at the plastic killed one pair of cutters.  I was hesitant to use the dremel’s cutting wheels or anything that could gouge the metal plunger.  But the light grinding brush wore the plastic down pretty well.

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A few careful scores with the exacto knife split the sleeve, and the plunger finally slid free. There was much rejoicing.

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After all that, the project board still reads “Replace flipper coil.”

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