Wednesday, May 12, 2010

You never forget your first...

I've been playing a lot of Ripley's Believe it or Not at lunch time. I have finally made it onto the high score list of a pinball game in the wild.

You never forget your first...

... unless your second follows a few minutes later.

Tuesday, May 11, 2010

Back in the shop - Pandora's Box Part 2

We left off with a cleaned, rebuilt, and nicely lit pop bumper.  The problem was, it was locked on.  I've got a couple of months of experience and reading under my belt now, so I know that I probably have a bad transister.

I know now, that to test your transistors quickly, you put one lead of your Digital Multimeter on ground, then test continuity to the metal tabs of the transistors.  I do this and I find Q17 has continuity!  Here's my culprit!

I feel really clever and smart, so I unplug the corresponding connector to the board and turn the machine back on, fully expecting the pop bumper to be silent.  If there's no connector, there's no short, and there's an unlocked pop bumper.

I turned on the power and "WHAM!!" it locks down.  I found that inside the front cover of my F-14 manual is a list of all of the solenoids and their corresponding transistor.

Q17 is labeled as "Flash Lamps".  Wait, so what number is the pop bumper?  (I've heard Jet Bumper and Pop Bumper, in the manual it's "Jet").  Q69?

Yep.  That one buzzes out also.  I checked all of my transistors and found that I had 4 of them out.  Jet Bumper, Flash Lamps, Left and Right Slingshot bumpers.  What I don't understand is why aren't the slingshot bumpers locked on?  I really wasn't looking at them, maybe they were.


I guess I have a lot more work to do than I though.

The pinrepair guide recommends replacing the pre-driver transistors as well as the main transistor.  After removing the board from the back box, I cut them all out and started on replacing them.

There isn't much else to say about this.  I cleaned up my flux, replaced the board, and everything worked great!

I have no idea why, but the slingshots are stronger now.  I have no explanation for that and no one on RGP did either.  I could be imagining it.  One person said that maybe just the act of taking off the connectors and plugging them back in made a better connection so the slingshot bumpers worked better.  I'm picking that reason because the alternative is admitting that I'm nuts.

I did OK soldering on the board with my 15w Radio Shack soldering iron.  But for this job I used my nice new Weller soldering station ($99) and it made a big difference.  The end result was the same, but I was much more confident that I would not lift the traces because the Weller has temperature controls.  Also, the soldering pencil was much more comfortable to hold and the tip was made for soldering on boards.  The old 15w jobber has a general purpose tip which means it does everything OK but nothing great.

I'm down to fixing my lit beacons, putting the new toppers on them, then moving everything to the nicer cabinet.  I'll clean each part as I move it.  After that is done, I'll have a fully functioning F-14 Tomcat which I will put in my basement.

Then the F-14 project will go on a break while I work on the Jungle Lord.  I'll start a new sub-blog for that machine.  Once the Jungle Lord is done, I'll start back on the F-14 to Remove the playfield, remove all of the mylar, re-set the inserts, and then clearcoating!

Sunday, May 2, 2010

Back in the shop. Opening Pandora's Box Part 1.

Someday very soon I will cronicle our adventures in eproms, but the story is still open.  That will have to wait.  I was able to finally get some time in the shop again today.  It needs cleaning very badly, but I really didn't want to spend time cleaning up instead of making my F-14 functional again.  I'll clean tomorrow, tonight, I get my hands on the pop bumper!

This is my Pop / Jet bumper.  It's a little dirty, it's not currently working because the coil blew, and also, anyone who knows the F-14 can see that there should be a lightbulb in there.  There's not even a socket for it.  I suspect that there was a problem along the way where the bumpber needed fixing, the light was removed, and the tech decided to just skip putting a new light socket in.

I've never done this before, so first I took a bunch of pictures, as per usual:

I'll spare the details.  There are a lot of pictures.

I then set about taking it apart.  I'll tell you what I did, then I'll follow up with what I should have done.

What I should have done:

With it all disassembled, I would clean it all up, install a new coil and new springs.  Finally, a new light bulb socket.

I may have made a mistake.  I like to polish up all of the metal before I put it back.  It's under the playfield and no one sees it, but when you lift the hood, I like to see shiney parts.  But I may have gotten overzealous here.  I don't know if that's brass colored for a reason or if they really oxidized, but I polished it right off.  It may just be me, but it looks like a surprised face.

With the parts assembled, it was time to put it back in place, then start working on installing the light.  I wish I had a picture of it properly done for you to see, but I don't, so you're stuck with how I did it!

Then it's time to lift the playfield and work underneath.

On the other side, I could not re-use a staple, and unless I wanted to simantle that side of the playfield, I could not staple it down.  Instead I used some shrink tubing to insulate the post.  I'll figure out a way tack that down.

With everything assembled, and an LED instead of the incandescent bulb.  Here is what it looks like.

So it was bright and happy!  But, why did I title this "Opening Pandora's Box"?

I turned everything on, and then tested the bumper.  It popped half heartedly 3 or 4 times and then WHAM!  It popped down and stayed down!

I turned off the pinball machine right away as not to damage anything.  Based on my reading, I now have a bad transistor.  I did some tests and confirmed that I didn't have one bad transister, I have 5.  I did check that a while ago and they were all fine.  I don't know what caused this but I suspect it was the shorted bumper coil.

More in the next post.