Star trek back online

Yesterday, I've managed to get the Star trek back together

As I (and Pinrepair) suspected what needed to be replaced was the Q16 transistor on the auxiliary (8 - driver board).

Here's the picture of the sinfull pcb, right before installing it.


For the first time in history I now have two fully functional pinball machines in my possesion and I wonder where all this will end.

Bigfoot ramp

I should have put this post together before, but I just couldn't find the time. Here are some pics of how I've fixed the pretty badly broken bigfoot ramp. It took me a whole week to do it, since epoxy glue that I was using takes around 24 hours to dry properly.

This is how it was broken:






My approach was the following:
I've cut out the missing piece from some sort of durable plastics and glued it to some other piece of plastics. This bit came from some old fax machine I found lying around. Here's what came out:


I than glued this bit to the ramp with epoxy. I took me two days, since I did not have enough clamps to do it all at once.



Half way there:


And the result:



I've been using this thing. I just could not find anything stronger on the market.


Luckily, this ramp is almost completely hidden from view, so the artistic impression won't count much, but I bet, this will hold the thing together properly.

Star trek on it's knees

I had an interesting episode with my Star trek the other week.

I was playing a game, when suddenly it started to behave a bit strange. It was popping the balls out during a regular gameplay, it lost the track of number of balls in play an was being all weird in general. A couple of minutes later a coworker came into room and started complaining about something burning. By that time I was already done with my (weird) game and i noticed that the machine was unable to put the balls into proper places. I also smelled something funny so i turned the machine off quickly. I took the backglass down and to my surprise, it was full of smoke!

After panicking a bit I pulled myself together and dug into the problem. It turned out that one of the diverter coils underneath the playfield simply melted.





What followed in the next couple of days was a classic procedure of:

• traveling home
  
• picking up the needed tools
• finding the replacement coil
• forgetting to pick up some fuses (F103 got burned when the coil failed)
  
• looking for a place to buy the proper fuses in Ljubljana
• etc....
  

Anyway, today I was ready to test the thing and it was also over in a second. The moment I turned on the machine the new coil fired and the next second the F103 fuse failed again.
I am now in the process of investigating, what could be wrong. Pinrepair has a whole paragraph dedicated to this exact problem with the Star trek exclusively, thus I have more than enough info on my hand. At a first glance it seems that some problems with the wiring took down some transistor on the auxiliary driver board, but I haven't found the time to check one or the other yet. I will report on the progress.

The DMD, Part II

I came back home today and naturally the first thing to do was to fire my whitewater.

To my surprise, here's what I found:

Now that's something that puts my soldering skills to trial. I started dealing with this issue immediately, so the first thing i did was to measure the voltages again. The two negative voltages were perfect this time (-118 and -106). The wrong one was +62 which read only 24 volts. Here's what pinrepair has to say about too low +62 voltage:

"The +62 volts is not +62 volts.
On WPC-S and earlier games, the positive DC voltage trace that comes from a very small bridge rectifier BR1 is physically routed underneath resistor R9 (1.8k 5 watt resistor). Because of the heat generated by this 5 watt resistor, and the current drawn from the bridge rectifier, this circuit board trace can become burnt and break underneath resistor R9. Because the trace physically runs under this resistor, the broken trace can be hard to see. "

And here's what my controller looked like:

Apparently this is exactly what happened to my board. I consulted the enclosed board schematics and here's the solution I came up with:

The DMD lightened up and I was really thrilled until I noticed that some sparks are flying around the board. It' seemed as that the cable I soldered on to the resistor was to close to the heat sink. I quickly turned the machine off. The board worked, so no other components were burned. I just had to replace the missing trace in some other way.

My second attempt looks like this:


And here's the result:

No sparks this time. I guess it's playing time again and let's see what the testing will bring.

The DMD

The first to deal with on my journey of bringing White water back to life was its non working display. We all now that display is a important part of every pinball, but you can't really tell how important, until one is actually gone. Imagine. No self diagnostic, no error reports, no tests, no settings, no score, nothing. Anyway, it was obvious that this is going to be the first issue to address in order to move anywhere.

The symptoms.
The DMD was not completely dead. It showed some life, but only around the edges and even there it was barely lit (again, no picture :(). It seemed that picture was getting through, but there just wasn't enough power to display it.

The diagnostics
Luckily I still had my Star trek at hand (loaded and ready to transport), so naturally, the first thing I tried was plugging the White water's DMD into Star trek. The thing worked and a 180€ that a new display would have cost me was saved. Since the display itself was flawless, there was only one remaining option left. There had to be something wrong with the Dot Matrix controller. After re seating all the cables that come from the controller a couple of times didn't worked I grabbed my multimeter to measure the voltages that come from the controller which gave me some answers. The first two pins read only -75/-63v while it should be at least -115 / -103.
The reason for non working display therefore is: Too low negative voltage produced by the dot matrix controller.
At this point I had to leave for Ljubljana where I live and work, so I just packed the controller and some tools and took the stuff with me. Unfortunately it'll have to pass a couple of weeks before I'll be able to work on White water again, but at least I'll try to get the controller in order till then.

The cure
The problem was solved by rebuilding the enitire high voltage section of the DMD controller.
Here are some pics.

1. The DMD controller


2. The (faulty) high voltage section


3. The shopping list


4. Printout from pinrepair


5. The tools used


6. HV section without components :)


7. Garbage


8. and finally... freshly rebuild HV section



The test
It's a good thing that I recently moved my Star Trek here to Ljubljana, so I was able to test my four hour hard work.
Here's the result, after switching the controllers:
HOORAY! The thing works.

Let me add that this was my first real attempt at PCB soldering, so I'm really really proud about the result.


The thanks
www.pinrepair.com. I'd be doomed without this site.