The DMD, Part V

I tested the DMD board today. It was over in i second. I turned the machine on and the R5 resistor exploded.

I'm running seriously low on ideas now.

I am a honorable player

I beat the grand champion on my Star Trek today. I almost forgot what a great feeling that is :).

I know 8 billion isn't that much, but I will improve it. I promise.

The DMD, Part IV

I was finally able to get back to my White Water this weekend. Of course, my primary goal is still to get the DMD controller back into working state. I just picked up the controller and some tools and took it back here with me

Here's the approach I'm taking now.


On the left, there is a broken White Water's controller and on the right the Star treks, that is all fine and dandy.

I measured the resistance of all the components and all the traces on both boards and try to identify any suspicious components, that might be causing too high negative voltages.

Anyway, the following measured quite different than on the working board: D4, D5 and D7 diodes. Q4, Q5 and Q6 transistors and R3, R4 and R6 resistors. These are the things I'll replace.

I guess I'm going shopping tomorrow. Naturally I will report about the results.

The DMD, Part III

The DMD controller failed again yesterday. This time it went with a bang and scared the hell out of a friend playing the machine.

At first it seemed that only the fuse failed, but after replacing it, the display looked really really weird. No letters, no graphics, just some sort of huge blob in the middle. I measured the voltages (Again) and the two negative voltages were waaaaaay of the normal readings. They read -152/-130.


What am I going to do about this one? I don't know yet. I'll see in a couple of weeks, when I'm back with my Whitewater.

It seems that if things continue to evolve in this manner I'll have to start a new blog and dedicate it to DMD controller exclusively. :)

Broken switches

Now that the DMD works again I checked out the whole bunch of broken switches that the self diagnostics reported.

Result: All of them actually work.

I guess my dad was playing and hit very little switches in a whole lot of games :).
Must I add that he is not a very good pinball player.

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.

Fun, fun, fun

After quick-fixing the both faulty switches I decided that it is not the time to begin with the other repairs or even cleaning yet.
I just didn't feel like it, so I ended up playing, playing, playing and then playing some more.
Man, this pinball is fun. Even though it is horribly dirty, the switches are all wrong and some ramps are not quite as they are supposed to be, it is so much fun it's almost criminal. This gotta be some of the best layed out playfields ever.
I can't remember ever having this much fun with the Hurricane. Thank goodness I got it back.