Thursday, 20 August 2009

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.

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