Quoted from johnwartjr:Well, what I'm getting from some other techs who I regard as quite skilled is these MOSFETS are rated at 20 volts, which is what the lamp matrix puts out - and it's quite possible that the lamp matrix in these games, while rated for 18 volts, would put out closer to 25 volts
So, the recommendation is
1) Just leave the board stock
2) Instead of zero ohm jumpers, perhaps install a smaller current limiting resistor
3) Find mosfets that are capable of handling higher voltage
Still doesn't explain why they work fine in WMS boards with the same voltage ratings and not in the DE boards...
I'm not done with my research yet. I did switch to SQT resistors on lamp matrix repairs some time ago, which guarantees the resistors are off the board and can get a little bit of air under them - but still doesn't remove the heat.
Why not simply take a Darlington like TIP125?
With a current gain of 1000 or so nothing gets hot in front of the the base.
Suitable mosfet with 25V could be FQP17P06!!!
Lake Charles, LA
