(Topic ID: 108195)

[System 11] Replacing Lamp Matrix TIP42's With MOSFETs

By UvulaBob

9 years ago



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Linked Games

  • Taxi Williams, 1988

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#1 9 years ago

There's a System 11 bulletproofing thread that mentions replacing the TIP42 lamp matrix transistors with MOSFETs. There's even a link provided to the suggested ones to use. This is the same replacement as in Vid's System 6 bulletproofing thread, which also says that you can replace the 27 Ohm, 5W resistors with jumper wires. I did some asking around a few months ago, and while I don't recall getting 100 percent confirmation, all signs were that the same steps are done with System 11's as they are with System 6's. I went ahead and replaced the TIP42's with the appropriate MOSFETs, and replaced the resistors with jumper wires.

I plugged everything back into my Taxi, and immediately heard a pop as at least one pre-driver transistor pretty much exploded. I quickly turned everything off and pulled the board back out. I did some extensive tests with my DMM on diode mode and connectivity mode. I suspect that I was sloppy with my soldering work and had some dead shorts between two pads in each of two transistors. I pulled the damaged MOSFETs and pre-drivers out, and all the other transistors appears to have been unaffected. I'm assuming that this is because I only had a few of my lamps plugged in at the time.

Anyway, before I buy some replacement parts, I was wondering if anyone can tell me about anything else I might need to do for this mod, or what else I need to look out for. I'd hate to order parts, put em in, triple check my work, turn it on and have another part explode on me. Is this mod as simple as it seems (and I just screwed it up) or is there something I'm missing when doing it?

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