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!

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....

Putting the heads on

After the move it was time to put the heads back on.

Unlike newer pinball tables which have a hinge for ease of transport, mine need to be disconnected and unbolted. Since all of the electronics and power are in the head, there are a LOT of cables.

The Hot Tip pinball, being a few years older should have been harder to disconnect. In fact it was the opposite, the Hot Tip table has snap connectors for every cable running between the two cabinets.
 


The globetrotters pinball does not. Each wire runs up from the base and directly to a board connecting to a board-edge connector.

So, after disconnecting everything it was time to pull the bolts.




Reversing the process was a lot harder. While keeping the door open, we had to hold the head up so the cables could be fished through the hole in the bottom. Then trying to move it around to find where the holes lined up - all without damaging anything!

Back up and running

After self-inflicting damage to my Hot-Tip table, I ordered a replacement solenoid for the right flipper.

I pulled the damaged solenoid assembly...

And put the new solenoid in

Then put it back into the table and fired it up.

Everything works but no right-flipper.

Checking the circuit, the wiring is pretty simple. There is a blue wire that runs from the fuse directly to each flipper solenoid.

I checked the voltages, I had voltage at the fuse, voltage at left flipper and nothing at the right flipper.

After scanning the circuits for some kind of problem I went back to the solenoid. The solder on one of the posts did not look very good so I resoldered it.....and lo and behold, it worked!

and the light has been replaced, so the table is back in operation!!

whew

Finally - a success!

After quite a bit of trying, I finally achieved some success!

 

Let me back up two months....

 

When I purchased the Hot Tip table, one of the solenoids was on continuously. I ran some diagnostics and even went so far as to unsolder transistors that I thought might be the problem and then test them. All the transistors tested ok so I still have no clue on why that particular problem is there.

 

However, after soldering the transistors back in, I put the boards back together and although the original solenoid still was in the same state, now the flippers would not work.

 

I pulled the boards again, double-checked that I had not shorted anything, reseated all chips, reflowed the solder on all the parts that I had touched....nothing.

 

The flippers have a very limited logic, they are not computer controlled as back then the computers were not fast enough, so the circuit for them is very simple on the schematics. Trying to figure out where the problem might be on the actual boards based on the schematics is really tough though and I have pulled the boards about a dozen times trying different things and checking ever more carefully.

 

Fast-forward to last night. I tested the fuse underneath the playfield. It should have had 28 volts on it since flippers, like all solenoids operate at 28v, but it did not, it only had about 5v......

 

.....great - some kind of voltage problem.....

 

 

......But it is really strange that it happened while I was pulling boards......

 

 

As I prepared to get out the multi-meter to start trying to follow voltages on the power-supply, I noticed a lone wire hanging inside the cabinet. It had a simple press-connector on it and was not connected to anything.

 

Was it supposed to be like that? or am I missing a connection somewhere...

 

After pulling up the playfield and looking around I found the other end of the wire, with the matching connector on it.  I connected them....

 

 

Low and behold the flippers started working!

 

Why every single other connection on the table goes through a board or a multi-wire connector and this one lone wire is all by itself I have no idea.....but at least the flippers work!

 

I have successfully made it back to the state the table was in two months ago!

More solenoid frustration

I made limited progress on finding what the problem with the solenoid was.

After downloading the user guide, it explained how to run the diagnostics. I ran the switch diagnostics which told me that none of the switches were faulty. I then ran the solenoid diags and the solenoid was on the whole time as the other ones fired one at a time.

The process gave me 2 important clues.
1 - during the switch test the solenoid was not on. This tells me it is not a short as a true short should have powered the solenoid even then.
2 - during the solenoid test the solenoid was on all the time. If it was shorted to a couple of other solenoids it should have powered off at least once as they all fired one at a time.

Based on this it is most likely something on the solenoid board. When the board is unpowered (during the switch test) the solenoid is off and when the board is powered tne solenoid is on all the time.

Hopefully it is an easy to replace transistor!

I labeled everything and pulled the board, then ran the simple multimeter test on the transistors without any success...sigh
So I have ordered a real testor. Keeping my fingers crossed!

Stuck Solenoid

One of the two problems with the Hot Tip table is that the solenoid powering the left bumper right above the flipper is on all the time. As soon as the power is turned on, about 3 seconds later the table boots up and the solenoid pops up:

I checked the wiring in the back, looking for obvious shorts:

But everything looked ok. Time to break out the multimeter...

I checked the switches, verifying they were open unless pushed on. I traced the wire (Blue with brown stripe) back to the board and verified power was working ok as when I pulled the connector from the board it did not turn on. Although it is still possible there is a short with some other connection on that same plug.

While rechecking the switches, I noticed a 3rd switch almost underneath the solenoid. It appears to be tripped when the solenoid fires. I checked it and found that it did not close:

It looked like I had found my problem! I carefully removed the switch. It is difficult to tell from the picture. They are close but do not make contact:

So, I bent the wire a little, put it all back onto the table and fired it up with high hopes!

Sadly, the problem still exists. Ugh, back to the drawing board.


Edit: After more research, that switch is a scoring switch - for incrementing the score and has nothing to do with firing the solenoid.

Problems with the Hot Tip Table

I haven't done an in-depth analysis yet but here are the problems with the Hot Tip table:

Shell:

The wooden cabinet is in bad shape. corners that have splintered badly, and the front center looks as though the wood was torn apart by a tow-hitch.

The top glass display is also in poor condition with multiple spots where the paint is missing or bubbling up.

Playfield:

The playfield is in decent shape with only minor wear and all graphics very visible - not bad for a table that is almost 40 years old! However - There are 2 solenoids that are not firing. Don't know if that is a wiring problem or dead solenoids, and if they are dead, how long till the rest suffer the same fate?

Electronics:

The boards have all been replaced! it turns out the previous owners did quite a good job of keeping it going, including purchasing replacement boards a few years past. So things look pretty good on this end.

The digital display is working good, no problems with lights or logic.

Another Table!

Out of the blue, I received a call from a really nice couple wanted to sell their old "Hot Tip" 1977 digital pinball table.
The price was good and the table has some issues but overall is in repairable shape so I am now the proud owner of two pinball tables!

A bit blurry but it is in my garage!