Rebuilding a pinball flipper

On the Harlem Globetrotters pinball machine, only two of the three flippers were working and they seemed sluggish. It was time to rebuild them!



Step 1 was to get it off the table. I unscrewed the plate everything was on and tried to remove it. No luck. It was connected to the flipper on the other side. I thought I would just pry the flipper off, no luck.

Finally after some head scratching I noticed the hex pins on the side of the shaft. It took awhile to locate the proper sized hex tool, but eventually I was able to loosen it.

Once it was removed I was able to take the whole unit apart.

Into the tumbler all of the parts went for an overnight cleaning and polishing.The plunger itself was sanded with 1000 grit sandpaper and then polished with some polish so it would slide through the solenoid with ease.

After a night of tumbling and cleaning everything out, it was time to put it all back together. I don't have too many pictures, but I do have a nice little 15 second video of the flipper in action. Check out the action on this thing!

Woohoo, now to do the other two!

And..... its alive!

The Harlem Globetrotters table is alive!

After all this time, the lights come on and the solenoids move and the sounds beep. Its amazing.

When I got it  back in 2015 ( link ) I never thought it would take this long. Part of it was my limited skills, and part was I seriously underestimated how much work was needed. I opened it up and it looked pretty clean so I thought it was a minor problem and I would be good.

live and learn.

But now after replacing a fuse that looked good but intermittantly did not make contact, its all in good shape.

I could actually try and play a game on it but the next step is to figure out what is wrong with the front door and the "start a game" switch which currently does nothing.

A gigantic step forward

Finally, finally, I have made progress with the Harlem Globetrotters pinball!

and this isn't a little progress, this is a LOT of progress!

I started working on the unit, checking and identifying cables and connectors. I thought perhaps I had plugged the wrong one in and accidentally swapped a couple. So I sat down with the schematic and verified cables and wires (J2 is a 28 pin connector, wire 1 is green with grey stripe: check) and marked them with Sharpie.

I dug around and found a 2-wire connector that was supposed to go to the sound board that had not been connected and plugged it in.

When I was finished I turned it on. Lo and Behold I heard a sound!! yes, the startup music played and most of the lights started flashing:

it works!

According to the manual, self-test #5 was the sound self test, so I pushed the test button.

And some lights came on, not all of them but some changed and this was the light test!

With baited breath I pushed the test button again. The second test was the score displays. These had never shown anything in the 18 months I have had the unit. They all came on and counted up!

Seriously - this thin has been dead for 18 months while I slowly worked it over and now it has at least partially come to life!

Test 3 was the solenoid test and as usual, the only solenoid that works is the "match" solenoid. None of the playfield ones do anything.

Test 4 was the switch test, it shows a zero on the displa, not sure what that means yet

Test 5 was the sound test, it makes a continuous changing sound so I think its ok.

Theoretically I should be able to start a new game. The MPU board is set for free-play.

But when I push the "Start Game" button, nothing happens. No spark of electricity, nothing.

Looking at the coin-door unit shows it to be in pretty bad shape:

coin door

so its possible I am unable to start a game because the door wiring is screwed up...



Back to the schematic, but hey.....its alive!!!!!

bad flipper switch

While looking at the burned out ball drain coil, I also looked at the flipper switches.

The left switch was in bad shape. It was all rusty and although I didn't get a very good picture, the contacts were touching even without the flipper button being pushed! that would be a real problem!

It was also off-center a little. So I pulled the rusty metal off and used a flapwheel sander on it which got rid of the rust quite nicely. 

I then used the dremel with wire brush to clean the contacts and finally needlenose pliers to bend it out a smidge. After some repeated banging around just to test, I think I have it set up correctly.

A problem I didn't even know I had! one more thing to check when working on pinball machines.

Ball drain coil repairs

on the Harlem globetrotter table the new MP3 board isn't resetting all the way. Of course there is no information with it such as what it means when it stops after only 4 blinks  of 6.

My guess is I have a bad coil or two, so let's take a look at them and see.

The most obvious starting point is the ball drain coil. Just looking at it, it looks like the paper cover is crispy, a sure sign it has over heated.

Checking the resistance on it confirms. it is only a few tenths of an ohm, basically a direct short.

After removing it I can also confirm that it's toasty, I am unable to move the plunger at all, a sure sign it has heated up and expanded inside.

I pulled it apart and set about the clean it.

Some soap and water later, it wasn't too bad but still had a lot of gunk on it, so I set to it with  some sandpaper. Finally I had it decently clean.

'The plunger was pretty crappy, and it needed to be smooth for easy moving, so I sanded it down and put some metal polish on it, it looks pretty good!

Now to get a replacement coil and put it all back together. One down and who knows how many to go.

Harlem Globetrotters pinball power trouble

The power troubles for the Harlem Globetrotter on Tour pinball machine appear to be solved!

After connecting the boards up, the test point on the board was showing low voltage. I was looking at having to pull components of the circuit board to try and solve the issue but after reading about Nic's "swab-polish-swab" technique where he wipes with alcohol, then polishes with a dremel and wire brush and then a final alcohol wipe - I decided to try it on the connectors. 

It solved the problem! Although they looked perfectly ok to me and I had seated and unseated the connectors many times, this time it seems to have fixed it and I was getting the correct voltage.

I plugged all the boards in, including my new MPU board and turned it on with great anticipation.

The lights came on, but the MPU board would not go through its self-test successfully. I could hear a coil pop and then it looks like it froze.

My guess is that I have a bad coil and its causing the new power board to pop its internal breaker.

Tme to start testing coils!

Power Trouble

Well, I didn't get the table up by New Years as I had hoped. I plugged everything in and started checking voltages.

According to the manual that came with the CPU board, do NOT plug it in unless the voltage at TP1 is 4.9-5.2 volts

Mine shows at 6.30 volts....sigh...and this is with a BRAND NEW voltage regulator board.
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more posting to the forums
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I get the reply back - "You should check this measurement at TP1 of the solenoid driver board, not the rectifier board."

Nice of them to provide 2 test points with the same name...sigh

Unfortunately, plugging the multi-meter in to the correct spot didn't work either...

As I suspected, I would need to replace the big Capacitor on the solenoid driver board...stay tuned!

Hot Tip Finally Working

After my soldering woes, I was getting close to throwing in the towel on the Hot Tip and start looking for a replacement board.

I pulled the board again, scraped some more, plugged the board back in, turned it on. And again - no solenoid action except one that was on continuously until the fuse blew.

I lifted the playfield and thought I might unsolder the solenoid that was having trouble to see if that helped, but when I looked underneath it looked to be in great shape and worked manually just fine. Besides, the only thing that changed was my soldering in the new DIP-Switch.

sigh...

Time to pull the board out and scrape some more, I must still have a short where I accidentally over-soldered the connections.

This time I noticed one of the chips was halfway out of the chip holder, one side was up high and the other down low. I pushed it in, scrapped some more and put it all back together.

Low and behold it worked!

Now that I think about it, it may have been the chip all along and I may not have needed to do the scraping at all.

But, now everything seems to work. In test mode, all of the lights, bumpers, switches, etc. all fire just fine. The game plays, scores count, everything is good except...


Now the flippers won't work.


...sigh...

I checked the fuses again, and traced the wires I could see, but whey would any of that have been messed with. All I did was unplug the circuit board a bunch of times. I was really getting nervous that I had somehow totally broke the table and was getting ready to post a "help me" message to the pinball forum when I had a thought tug at me. I seem to recall something similar happening on the table. I could not pin it down and I spent all evening trying to remember. Then just as I was heading to bed, I remembered!

There was an extra wire on the connection between the head and the body. Although I never touched it, it was worth checking.

Low and behold (again) it was disconnected!

I reconnected the wire and the flippers started working. It appears the table is back to functioning again. But it was past bedtime so I didn't have much time to try out the DIP-switch and see if it worked correctly.

Today I dug back through my posts and found the relevant one.  It details exactly the same problem I had. I don't know why the wire was disconnected, it doesn't plug into the boards I was removing, I must have just hooked it somehow during one of the processes. But hey, at least it is up and running!

Harlem Globetrotters Soldering

Now that the box for the Harlem Globetrotters pinball table is painted and looks good, I am starting to put everything back together.

As you may recall I pulled everything out of the header ( link ) and painted it.

Time to put it all back in. As I re-assembled the light-panel (The wood with the lights on it) I noticed one of the LED displays had what appears to be burned out resistors on its little board:

Burned out resistors

Another soldering disaster! 

While I was able to get the resistors out of the board, I managed to deconnect the tiny traces and ring that the solder is supposed to connect to - why is my soldering so bad???

I spent all evening soldering them back in, using a meter to verify I have connectivity but I have no way to test them until I get it all put back together.

Looking at my soldering iron, I am going to try and lower the temperature on it. I have it set all the way up,  under the theory that hotter means faster but it could be its just too hot and is screwing things up. We will see if that helps.

In the meantime the Harlem Globetrotter table awaits reassembly as somehow I managed to lose one of the back pieces of sheet metal. Not a big deal but it means a wait until I can go back to the store for more.

Hot Tip Wounds

When my son arrived for vacation, the only pin I had in working condition was the Hot Tip, and it had a problem. The DIP-Switches on the motherboard had broken and I was trying to manually set things by sliding the tiny sliders with a pair of needle nosed pliers.

Once he was gone I decided it was time to replace the switches. It seemed easy enough, unsolder the old switch, solder on the new switch.

The old one came off easily enough, and I soldered the new one on:

The new dip-switch

However when I turned the system on, it groaned (hummed) and made weird sounds and woudl not work.


....sigh....

so I reflowed the solder intro each socket. No change...

so I reflowed and added more solder. this time (or perhaps the first time) I noticed that it looked like I had melted the green stuff and there might be a connection under it:

Arrgghh.. another self-inflicted wound!

I ended up scraping it away with a knife. But I have been unable to test it as all the fuses are blown.

I replaced them but the one that runs the solenoids keeps blowing, but I noticed one of the solenoids was stuck in the on position and it finally went back, but that was my last fuse... so back to the store to buy another batch of fuses and see if that was the problem or not....

Bingo Pinball not resetting

After some discussion online with the experts on what my next steps should be, I plugged the United Brazil Bingo Pinball machine and and manually set it up a couple of games (by pushing on the lever).

When turned on, it is supposed to rest back to zero. I plugged it in and turned it on:

and it runs! but it never resets back to zero.


After digging around and looking at it, it looked like the solenoid that was pushing the reset level wasn't doing its job....seemed like a straightforward sticky solenoid plunger.


I pulled the unit out of the Bingo:

and pulled off the solenoid.


Surprise! it was in great shape, not mushroomed or sticky at all. In an effort to figure out what is going on, I managed to film myself working the unit manually:

Analyzing the movement, it looks like the little lever connected to the tiny spring is not moving the way it should around that shaft. I'm going to pull off the lever and clean the shaft.

A big thanks

A big shoutout to the previous owner of my United Brazil bingo pinball game.

In order to get the Brazil upstairs and into my workarea, I had to remove the topper. No big deal, those come off all the time. But in the ancient pre-electronics era when this thing was made (circa 1956) they didn't have modern connectors.

So what did they do?

They used an ancient knife-connector style of thing. The problem is that the "knives" fit in multiple connectors.

I searched desperately for some method other than the "try it and see if smoke comes out" method. Fortunately the previous owner was smart enough to put a dot of colored paint on each connector - you can see the yellow dot easily on the top of the leftmost connector.

Then it was simply a matter of checking each "knife" and matching up the colors!

As a side benefit of this work. The lights now have come on, so apparently part of my problem was just corrosion on the connectors!

Cleaning the Pinball Wiring

With all the postings about my Steampunk-inspired lamp, it is hard not to forget that I am still working on the renovation of my Harlem Globetrotters World Tour pinball.

One of the key pieces is getting the wiring cleaned. It sounds simple to clean a wire but in reality you've got a large bundle of wires in poor, oily, dirty condition and it can be a lot of work to clean them.

After reading of several different techniques, I opted for Vid1900's guide. He basically says to throw it in the dishwasher, it will be fine!

Wiring harness in the dishwasher

So it was with considerable trepidation that I put my precious wiring into the dishwasher, worried about the colors on the wires (what if they all come out white!) worried about the connectors (what if the old plastic softens and the connectors fall out) worried about the moisture (what if water gets under the insulation and rusts the wires)

Per the recommendation, I put it on "High Temp Pots and Pans" rather than "gentle," crossed my fingers and pushed "Start"


90 minutes later I had a perfectly clean wiring harness!

Cleaned wiring

it looks like everything worked perfectly. My blue tape with labels on it even survived. 

I fired up the air compressor and blew out the moisture still trapped in the connectors just in case. But it all looks good!

whew

THoughts on a lamp switch

I've finished the basic design for the Steampunk-inspired floor lamp. But although the individual lamps have switches in their bases, I wanted a central switch that would turn on/off the light inside the box as well as the lamps.

It ought to be something appropriate for the design of the lamp.

I was thinking of something like a portion of the box rotating to turn the light on/off or something like that.
Looking around the web for inspiration I found a pretty cool "vintage industrial light switch" on eBay but it was over $100 - no way!

still, perhaps I can take a regular lamp switch and make it look appropriate, worst case I can do some kind of pull-chain with a real chain or something.

Backboard is complete!

After going through 2 soldering guns and 1 soldering iron I have finished soldering a new ground wire on the backboard for the Harlem Globetrotters Pinball.

It is not as beautiful as I had hoped to make it, but it was quite the learning process.

Next up is cleaning the wiring harness for the head unit. Time to head for the sink in the garage.

Soldering Iron woes

My old 65 watt soldering iron that I had in high school seems to have given up the ghost. It was getting hot only intermittently.

So I purchased a nice big beefy 140 watt soldering gun to finish up my soldering with. With almost double the wattage it should heat up and melt the solder twice as quick!

About 3/4 of the way through soldering the backboard the gun died. Cheap modern crap! So this time I purchased both a new gun and a little soldering iron.

After about 1/.2 hour of soldering, my new gun died.....dammit!

I was looking at the label, examining the manufactures info when I noticed a tiny statement:

It might be hard to read, it says "Duty Cycle: 1 min on, 4 min off"

So basically it is supposed to only be turned on for 1 minute at a time and then must cool down for 4 minutes before it can be used again!

I'm not sure what kind of soldering procedure that would work with, but it sure doesn't fit mine. Fortunately I also purchased a soldering iron. Slow but steady for me from now on.

Wide Ground Wire woes

This is one of those "Who knew?" type of things.

When I was purchasing parts and equipment for the repair of the Harlem Globetrotter Pinball table, I knew I wanted to replace the groundwire. Although it was not in too bad of shape:

The poorly implemented runs bothered my sense of perfectionism (those wires should be parallel!!) and this seemed like a great time to try out a complete redo.

The old groundwire is a small one, so I purchased a big fat one. After all my Dad always said, no matter what it is, if a little one is good, then a big one is "gooder!"


The problem with wide ground wires is they don't curve very much and while it is possible to do the bed-over turn, its tough to make it look good.

Couple that with my poor soldering skills and you end up with less than beautiful results.

When I started this, I hoped to make something that would look good enough to be in a glass case, where people would ooh and ahh over how beautiful all the behind-the-scenes work was. Now I'm just hoping the lights all light up.

Here are a couple of shots showing the difficulties. Its not bad when the wide ground wire only has to make a couple of bends, but when its a zig-zag pattern it really makes it tough to do a good job!

not quite what I was hoping for in the "beautiful work" department...sigh

Light Panel for the Harlem Globetrotters table

Now that the computer table is almost finished - just waiting for another set of lights - I have turned my attention back to pinball.

To recap:

The Harlem Globetrotters table was in serious need of topper work.
The glass was in good condition but:
There were boards missing.
No power was going to the table.
The case had flaking lead-based paint
There were an unknown number of  light bulb problems on the light board.

So to start with, I pulled out the light board (the piece of plywood that all the light bulbs are attached to) and took a look at it.
The board wasn't in too bad of shape, but it seemed like a good warm-up for the full cabinet, so I took pictures of where all the old wires were and pulled them all out as well as the lamp holders the wires were soldered to:

I threw all of the lamp holders into the tumbler:

Although they are not going to win a shinyness contest, they look much better and hopefully will work better without all the corrosion all over them.

The wood panel itself was sanded down (being careful to wear a lead-based paint rated mask,) sealed and repainted in the brightest white I could find.

Now comes the slow work of stapling and soldering the wires and the sockets back into place. I've tried to be a little more careful about 90-degree angles and keeping things parallel where I could, just to make myself happier. 

The work is coming along with about half of the ground wire in place

Nightmare with a soldering gun

After 2 hours of work, I am still not finished removing the corroded and burnt parts from the power board on the Harlem Globetrotters table.

 The removal really highlights my lack of skill with a soldering gun and just how hard it is to do a decent job. Especially with the multi-pin connectors.

I started out removing the burnt fuse holders. This wasn't too bad, though the connectors were large and it was hard to unsolder them enough to pull them out.

Then I tried to do the connectors. After several passes with the solder-sucker there was still enough solder to keep them from coming out, so I had to try and heat all of the pins at the same time enough to pry out the connector with a screwdriver.

A complete nightmare. I had to hold the board with one had, hold the soldering gun with the other hand, hold the screwdriver with the third hand and try to pull on the board with the fourth hand.

Trying to unsolder all 8 pins at the same time didn't work, so I tried to unsolder a few and then pull the edge of the board up. Backbreaking work hunched over the board. The solder gun got so hot I couldn't hold it, the board got so hot it burned my fingers.. and after 2 hours of work I am still only partially finished.

Whats even worse is that I am destroying the board in the process.

As you can see from the pictures, it is not a very good looking board. Many of the pads that you are supposed to solder to are gone. My only saving grace is that this is the simplest easiest board there is. Giant traces 3/4 of an inch wide. several pins in a row all connected together.

I may be able to get this board working but it really shows just how hard doing board work really is.

Repairing the Globetrotters Power Board - stage 1

The Globetrotters power board is in bad shape. Scorch marks, burned components, missing pieces, etc.

However, the good news is that I can easily buy a replacement, so..... that makes it a perfect candidate for my first board reconstruction!

If you recall from the last entry, this is how the unit started.

Separating the board meant unsoldering each one of the wires:

But at last, I had it separated!

Unfortunately, my soldering skills are still not quite as good as they should be. But in my defense, removing the big Bridge Rectifiers (essentially big square boxes soldered to the board) is hard. All 4 contacts have to be heated simultaneously while the board is held in the second hand and the rectifier is extracted with the 3rd hand.

Anyway, as you can see, I managed to remove the little metal slots and pads where the solder wen through the board:

I still have the big connectors to remove and I need to check the resistors and diodes to see how they look, but I can't do that while they are under a layer of dirt and grime......so, into the bath they went!

After 1/2 hour in concentrated soap and with a light scrubbing from a delicate paint brush, the board looks much better:

Next step, remove the rest of the components I plan to replace (multi-pin connector and the fuse holders) then brush with a tougher brush (toothbrush)