Thursday, May 28, 2015

Cleaning the dropdown - part 1





On the Star Trip pinball table, one of the dropdown targetswill not drop. When the ball hits it, it will usually not drop at all, sometimes it will slowly sink halfway or if I push it it will go down where it is supposed to. The other two work just fine so it was definitely a problem with the one unit.

I thought it might be a bad spring, not strong enough to pull it down and since the others were working this seemed a perfect project as I could compare the good ones with the bad one.

So I set about pulling the mechanism off the table and finding out what was wrong:
At first check, all looked ok. Nothing was obviously broken or bent out of shape.

After unsoldering the connections, I took it apart:



It wasn't until I had it all apart and moved things around that I found what I think was the problem. The spring seemed ok and was about the same tension as the other springs, but the whole mechanism was incredibly dirty!

This is the plunger that supposedly slides easily through the solenoid coil, it should be a shiny smooth polished rod:




My polishing tumbler is still on order, so I sprayed everything with engine degreaser and wiped it all down, then reassembled it.

It seemed to work smoother and I eagerly put it back on the table, soldered the leads back on and fired up the table....




Only to have the fuse blow out immediately!

I checked the solder connections, everything looks good....but now it doesn't work...sigh


(more to come)

No comments:

Post a Comment