Wednesday, March 31, 2010


I spent $7.50 and ordered the new chip.  But I didn't want to give up just yet.  Someone in RGP said you'd be surprised at what would cause a signal from the chip to go funny.

You may remember that my batteries came corroded and the main board looked like this.

When I cleaned it, I was really too easy on it.  I lightly brushed it until it looked OK.  But there was just too much of a connection between the "j" being one of the corroded traces and the "j" being the segment that wasn't working.

I tested some sanding and cleaning techniques on a piece of junk board so I could get a feel for how rough you can be on a board before you break a trace, and it turns out that they can be pretty tough.  I then cleaned the system board more agressively.

I used a scotch bright pad, the one that's plastic, but equavalent to a 000 steel wool.  (Don't use steel wool!  You don't want conducting junk flaking off  all over your board!)  I used it and cleaned the small section of board.  I then used a magnifying lense and a dental pick to make certain there was nothing between the traces.

When I fired up the machine, the "j" segment worked!  However, I've decided that the corrosion really needs to be cleaned up, so I'll still be removing the two chips, cleaning the area thoroughly with vinegar, cleaning it  with the scotch bright pad, and then finally soldering in some sockets and replacing the chips.

Here is what it looks like now:

Monday, March 29, 2010

Good news, bad news?

I feel a great victory has been won, but at the same time, I'm worried that things may be worse than I thought.  We left off at my display.  Player three had been successfully replaced with a $10 piece taken from a junk pile.  All that was left were figuring out the "A" and "J" segments of my alphanumeric displays.

I read the guide on checking segment problems on a system 11 machine.  I was held up because I had neither a logic probe nor an oscilloscope to diagnose problems.  Luckily, I was able to borrow an oscilloscope.  Also, I called my friend Eric M. who has experience setting them up.  He was an enthusiastic partner in getting these display problems resolved.

We were both pretty certain that if we found the solution for one segment, it would be the same for the other.  Boy were we wrong.  On with the story:

First, I determined that the display board for my F-14 had come out of some other Williams pinball machine from that era.  However, I wasn't able to figure out which one.  I checked the schematics on for other machines from that era but they were too hard to read to be certain.  Bad scans?  Bad source materials?  Can you read this?

I couldn't.  I figured that since you could take a display board from almost any system 11 pinball machine and swap it out, even if the board schematics were different, the connector pins had to be the same.  (J1) was the common denominator between all of the boards for the "A" and "J".  So we set out to identify and document the paths for the "A" segment (J1-19) and the "J" segment (J1-12).  Then, once that was done, we would start to test each link along the way.

This is me figuring out where each line started and ended.  Eric took notes.  I stopped documenting at the "IN" side of the 7180 chip.  This is important to know for later.

We took notes and then Eric set up the scope.  Here are Eric's disembodied hands setting up the o-scope:

Because there are two different voltages, we had to adjust the scope twice.  Everything up to the 7180 chip was low voltage, 12v I think.  Everything after the 7180 was -100volts.  At first we were a little worried about the scope handling that voltage.  Eric had never used it for more than 5 volts.  We read the manual and our fears were laid to rest, we were OK with -100 v.

First we tested known good segments so we knew how the wave should look.  This is what we saw on good segments.

This was a known good pulse.  So we expected to see something like this on the "A" segment:

 But we didn't!  We got a good pulse all the way through the 7180 "out" pins on the "A" segment!  That was a relief.  I thought I was going to have to spend $20 replacing the hard to find 7180 chip.  Since the chip was fine and the resistors after the chip tested within spec, I must have a bad trace between the out of the 7180 and the glass display.

We figured we would get to that during the "repair" phase.  Next we set our sights on the "J" segment.  We were hoping to find that it was the same thing -- a bad trace.

See our careful notes, well, we knew what they all meant at the time.

We tested the "IN" for the "J" segment on the 7180 and the signal was bad.  It wasn't gone, it was just really really weak.  That was a relief because we figured that the problem must be with the cheaper 4050 chip. 

We checked the out (Pin 6) on the 4050 and the signal was weak.  That must lock it right?  Wrong.  We checked the "IN" on the 4050 (Pin 7), weak.  Ah, so then it must be a bad trace from the J1 connector to the 4050!

I buzzed out pin 12 to pin 6 and there was no continuity!  But then we noticed that I was checking the wrong pins.  It gets confusing when you're flipping a board over back and forth.  I checked again and the trace was OK.

Then we thought it was a bad ribbon cable!  That can happen!  It's the next thing in line.  We tested it and, nope, that was OK too.  We kept testing signals until we were completely off the display board and on the actual "J" segment pin of U41 on the main board.

The weak signal is coming off pin 3 of U41, the 6821 chip on the system board!! 

Disaster!  That chip is huge!  How much is it?!!?

It turns out that it costs about $6 - $7!  What a relief!  I'll order one tomorrow with a new socket!  Hopefully that's the end of that problem!

We then returned our focus to the "A" segment.  We checked every trace and found, with a Digital MultiMeter and a magnifying glass, that the very last trace before display pin 1 was broken.  It was very hard to see.  We couldn't get it on camera.

I took tweezers and pulled the trace off the board.  The trace had lifted from the board and I didn't want it shorting on anything.  Here is the trace pealed away from the board:

With Eric manning the camera and being a third hand, I soldered in a jumper.

Completed work:

And does the "A" segment work?  You bet it does!

I'm down to fixing just one more segment, and we're fairly certain that U41 - a 6821 chip - is the problem.  I'll update you when I get the new chip in!

To conclude.  I said it was important that I stopped checking traces at the 7180 chip when I was tracing out each leg of the circuit.  I should have gone all of the way to the display.  Next time I'll check each trace segment end to end.  Had I done that in the first place, I wouldn't have needed all of the fancy equipment to fix the "A" segment.

We also guessed wrong that the "A" and "J" problem were the same.  They actually couldn't have been further from each other.  One was a bad trace at the display end of the circuit and one was a bad chip all the way back on the system board.  I'm glad we tested each separately otherwise we would have wasted more time chasing an assumption.

We both got a real high from tracking down these problems. 

Is it wrong to hope something is wrong with a machine so you get to fix it?

Saturday, March 27, 2010

Better to be good or lucky?

Today I went to the Midwest Gaming Classic in Brookfield Wisconsin which is just outside Milwaukee and less than 2 hours from my house.  There was a lot to look at and maybe once my head has stopped spinning I will post about it.

This is a work journal though and the work I did was on my display.  While up at the classic I dug through a "junk" box and found this:

It's a 7 digit numeric glass display from a Williams game older than my F-14.  I thought that since it was Williams and I'm sure they wouldn't re-invent the wheel, this might be the same display as is used in my F-14.  I paid $10 for this.  Not knowing if it worked or not I probably should have paid $5.  I'm just not savvy enough yet.

What I would need to do is unsolder the display from this board, unsolder my bad display from my board, then solder this "new" one in place.  I had no real concrete evidence that it was the glass display on my board that was actually the problem.  I checked the voltages on the pins of my working and non working displays and found them both to be the same. 

I figured that if the voltages are making it to the display that if it was good, it would do something.  But it was black.  The downside of my gamble was that I could go through all of this work to put a bad display in place of another bad display.  I could have tested the display in another pinball machine, but I don't have one that works.

Here is a pictorial of the process:

This is a desoldering tool.  I will use this to heat the solder on each connection, then release the suction ball and the liquid solder will be sucked off the board and into the tool.  Here's a tip:  Before you squeeze the ball again to prepare for the next "suck", make sure it's over a paper towel or something and not over the board -- you'll shoot molten solder back out of the tube onto the board!

On the left you see where I've unsoldered the pins (is it unsoldered or desoldered?)   The pins are pretty big so this was pretty easy to do.

Now that the pins are all unsoldered, I need to remove the display from the board.  You can see it's attached with two sided foam tape.  I used a razor blade from a utility knife (no knife, just the blade) to separate them.  I was being carful to not cut myself while also cutting on the board side.  I was cutting on the board side because if damage was done I wanted it to be done to the board which I was going to throw away, not the glass I was re-using.


OK, Onto my board.  I have to repeat the same process on my board.

This is the F-14 board after the display was removed.  You can see that there is a lot of left over flux.  I used a toothbrush and a little acetone to clean the flux off the board.

Here is an "After" shot, much better!

Here the pins are all fed through the board.  The toothbrush isn't the only handy dental tool.  You can buy a set of dental picks really cheap from Harbor Freight tools.  This was key for getting all of those pins through the holes on the board.  before soldering, I "backed the pins out" a little bit.  I didn't want to solder that much pin, plus I thought I might need every bit of length of those pins on the display side.


So did it work???  Did my $10 gamble and 30 minutes of board work pay off?

It works!  There is a problem though.  The pins are just a HAIR shorter on this display than the current displays.  It's making it sit weird.  You can see it here.  Since I know it works, I'll cut the pins and use the pins from the bad display to extend the length enough to make it sit correctly.

I excitedly showed my wife and she said, "Uh, good."  and left the room.  I stood for a few minutes appreciating my work, a little disappointed by her reaction.  I found her and said, "I'm a little unsatisfied with the enthusiasm you showed for my victory."

"To be honest, I don't really understand what you were showing me",  she said.
"Well, I fixed a $200 board with a $10 junk part."

That's when she gave me the high five.

Now to fix this:

Friday, March 26, 2010

Oh, no... oh, yea!

It's called Jungle Lord.  It is VERY dirty and needs a lot of work, but that playfield is really nice for this old game.  I got it really cheap.  Now I can stop worrying about what's next after the F-14 is done.

Thursday, March 25, 2010

In case you were thinking I might make some kind of business out of this:

Let me start by saying that I never had any intention of making any kind of living doing this.  I did think that maybe I could buy a machine cheap, then fix it up really nicely, sell it, then take the proceeds to buy 2 cheap machines.  The idea is to build the stable of pinball machines so to speak, also to gain more money to get into the more expensive pinballs.

This new hobby also couldn't cost my family anything.  I "borrowed" money from our budget to start this hobby and I need to pay the family back.  I swore we wouldn't miss a vacation or something because I spent our money on pinball machines.

I've put up for sale a lot of stuff I had laying around so I could pay my budget back right away. I've almost got that accomplished.

I put together a spreadsheet of all of the things I've purchased and a worst case cost of those things that I still need.

I'm new to this hobby, so I have no connections.  Having no connections means I may have paid too much for this F-14 Tomcat.  But I was itching to go and it was cheaper than I had originally budgeted.  Also, having no connections means at this time every part comes at a premium.  I have no buddies with 8 year old plastics in a drawer somewhere that they'll sell me cheap.

I have a lot of nice F-14's on my watch list on eBay.  Not one is priced lower than $1,495, which you would think would be encouraging.  But not one has sold.

My only hope of staying right side up on this pinball machine is to find the toppers for less than $135, find replacement plastics cheap, and to repair the backboard display instead of replacing it.  I could go without the decals, but, it needs the decals.

I have had a VERY good time working on this machine and I can't wait for more.  I'm not in this to make money.  I just posted this to burst the bubble of anyone who is thinking of starting the hobby to try and make money.  You'll need one of two kinds of connections.

1. Someone who will sell nice machines, cheap.
2. Someone who will buy machines for a lot more than they're worth.

There is one last problem.  I really like the F-14.  I don't want to sell it.  I want to play it.

Saturday, March 20, 2010

Treasure found in the nether regions of the cabinet

I vacuumed my cabinet out today.  Before I did, I dug around in the back corners with a magnet and my hand.  This is what I unearthed.  There look to be parts from a coil rebuild and some leg bolts.

I scored a nice little T-20 security torx tool.  There are two plastic pieces though, I don't know where they come from and they look important.  I'll have to ask R.G.P. and also look through the manual.

Thursday, March 18, 2010

Wednesday Night Maintenance

Many things happen Wednesday's when I have Chad's help.

The spinner switch was fixed.  It just required some bending.  There was a diode loose on the right (currently good) flipper which we soldered back into place.  We replaced some lightbulbs, did a trial on a couple of LED's, cleaned up the grunge with Novus 1, and finally, yes finally, checked all of the fuses.  It turns out I had 3 over rated fuses in the box.  They were only off by .5 to 1 amp, but that can be enough to cause problems.

Also, we replaced the left flipper which had stopped working.  I wonder if it stopped working because of this artful wiring job some "tech" did:

Yea, he even used wire nuts on the capacitor.  I think this was actually more work than just soldering it.  I wonder if this wiring had anything to do with the coil failing.

There's only one other interesting thing about this flipper rebuild.  There is a secondary switch on the main flippers.  Here it is pre rebuild:

Here is the after shot.

The rebuild kit only came with one switch, so we cleaned up and reused the original switch. 

And here it is from the other side.  No more wire nuts.

Edit:  I thought that I should add a couple of things.  First, I bought two rebuild kits that included the parts to rebuild 4 flippers.  I rebuilt the top left flipper, then pulled parts out from the same bag for the lower left flipper. 

The plunger assembly all comes together and apparently, it matters which side they go on.  You can't use one rebuild kit to rebuild two lefts.  They are meant for one left and one right.  You may be able to take apart the linkage and flip a part over so the tab that moves the EOS switch is oriented correctly.  I haven't checked that yet.  But it's something to think about when buying a rebuild kit.

Second, the game is finally playable.  I posted 1.8 million last night.  I'm sure I'm not breaking any records but I'm starting to figure out the rules and flow and I have to say that I'm liking it a lot. 

This past week I fixed a doorbell, our clothes dryer, and my pinball flippers.  I like fixing things, but fixing the pinball machine has a much better effort to fun ratio.  It's nice that my clothes are dry, but I'm not inviting any friends over to have a beer and dry clothes with me until midnight.

Tuesday, March 16, 2010

Digging through my stuff

Old laptops, telescope, hard drives, tape drives... gotta get them up on eBay to pay for this new hobby.

Tidbit learned

All of the system boards have serial numbers.  If the machine was new, all of the numbers would match.  The fact that very few of mine match means that many parts have been swapped out over the years.

Monday, March 15, 2010

Display Problems

This is driving me bonkers.  I just checked all of the traces from U41 on the main board to J22, the connector.  I toned out everything on one side of the chip.  Everything was going OK and making sense.

I'm trying to do some recommended tests on the chips on the display but things aren't adding up!

  Schematic of the display board showing U1 being a 6118 Chip.

Picture of my board showing U1 being a 4050 Chip

Is my display board out of some other game?  I need that schematic!  Or am I just reading this wrong?

Here is the whole board:


Sunday, March 14, 2010

Finding more to do

I took off the rear plastic so I could get to the rear rubber. It had rotted out completely and I wanted to get a new one in there so I could play. By play, I don't mean "I'm done!" but just test plays.

I found more problems than the rubber. First, boy is it dirty! I know it's not time for finishing, but leaving it as dirty as it is will only cause problems. I'll be vacuuming it out and cleaning up all of the dust.

The targets have foam backing. It's missing. The targets are $6 each. I wonder if I can refurb them or if I'll need to buy all new targets.

There were also som holes where something must have been screwed at one time. I wonder what those are for?

I'm coming to the conclusion that I have to stop worrying about making things perfect. I wanted to make everything as good as possible, but this is my first machine and I'll drive myself crazy trying to make it perfect. I'll settle for clean, functioning, and reliable. I don't have enough experience for perfect and this machine has been too hacked to hope for that anyway.

Flipper Rebuild

I picked up my coils and the other miscellanious small parts to rebuild my flippers this morning. I had a lot of stuff to do, so it wasn't until 3 PM that I could start on the rebuild. I assembled things and disassembled them at least a half dozen times to get it right... I hope I have it right...

First, the thing on the left is a bushing, the thing on the right is a grommet. I kept calling the bushing a grommet (see previous posts). Don't do what I did. It created unecessary confusion at the supplier.

I started by putting the new bushing in. It takes a little pushing and prying to get in place. I used needle nose pliers to pinch, push, and pull it in place. Then I put in the new stop and last I put the coil in place.

The coil didn't fit correctly. I thought maybe it had something to do with the coil sleeve, but that sleeve came with the coil in that direction. I thought it must be right, who am I to question?

So I did what a guy who used to work in a body shop does. I used pliers and "adjusted" the stop. I figured that maybe it came from the manufacturer a little bent or something. The coil fit a little better, but you can see here what happened.

I put the front bracket in place before I realized that the plunger wouldn't go in with it put together. So I took it apart again. I put the spring and plunger in place and when I tightened it all, the sleeve pushed out of the front bracked about 1/8 of an inch. It was then when I finally realized something was really wrong. I checked the coils I hadn't touched yet and yea, it was backwards.

After I figured out what I had done wrong, I bent everything back the way it was supposed to be and it all lined up correctly... like they meant it to.
I soldered the EOS switch and capaciter (with heat shrink tube on the capaciter) before I put them on the mechanism. Another note, put the heat shrink on before you solder the capacitor in place. I forgot on the first side and had to redo it.
Here it is, all soldered together. I used nice new clean green 18 gu. stranded wire.

I wasn't sure how the bushing screws went in at first. The plate is threaded so I tightened the screws in first, then I used the nuts to lock them in place.

Here it is, all together, correct, I hope.

The next step was to get this new flipper in place.

Here is the underside of the playfield with the flipper post coming through.

I screwed the flipper assembly in place and tightened it just enough so the flipper wouldn't swing around. I adjusted the flipper so it was in line with the ball exit then tightened it the rest of the way.

Before I soldered the wires back in place, I put some cardboard down so I wouldn't drip solder on anything. I used a clamp to hold the cardboard in place against a strong bracket.
Here it is, all done. I fired up the game and it worked great. The bottom left flipper was still weak, but I already knew I would probably have to rebuild it. I played for about 15 minutes and asked my wife if she wanted to try. She did, but before she got to the machine, this happened. I guess I used the last few flips. Sorry hon, gotta rebuild another flipper before we can play.