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Reasons smd pcbs are ****e no 75!!

Yes from a usa machine i think. Getting one of these machines myself, though am in team ultraman now. One reason i have one coming was to be able to assist people with tech stuff and repairs on new board sets, though i'm not sure what could be done if the board destroys itself like this

If the mosfets were plate through if would still destroy itself but would be less likely to burn whole in the board aswell. Having smd parts tight against the pcb just ask for trouble...

Real interesting issue on supposedly a decent new board design by ben heck. What the hell happened and why didnt a fuse offer some protection... Very strange..
 
myPinballs said:
Yes from a usa machine i think. Getting one of these machines myself, though am in team ultraman now. One reason i have one coming was to be able to assist people with tech stuff and repairs on new board sets, though i'm not sure what could be done if the board destroys itself like this

If the mosfets were plate through if would still destroy itself but would be less likely to burn whole in the board aswell. Having smd parts tight against the pcb just ask for trouble...

Real interesting issue on supposedly a decent new board design by ben heck. What the hell happened and why didnt a fuse offer some protection... Very strange..
Click to expand...
There has been some dodgy wiring and bad crimping with these machines and now some mini pc HD issues where it’s stuck on the boot menu. There are more things to look out for and I wish I made a list now as I can’t remember them all.

Going to be giving mine a good looking over when I get it, hope I don’t get one that’s blows like that. Something shorting somewhere surely and you can’t just keep changing boards if it keeps doing it and that’s the 3rd board they have put in that machine. If there was some schematics you could probably trace it to something but at the moment they are saying you need to trace wiring to work things out.
 
I don't know what SMT driver transistor they've used here and if it had internal flyback diode back EMF dampening but I've certainly had fried drivers due to the diodes on the solenoids going weak or open circuit / dry jointed. They'll not take back EMF for long until they pop! Any further boards will also suffer the same fate until the true fault is found.

I'll confess I've used these kind of SMT mosfets in my own work but I've been an industrial PCB designer for 10+ years and know from experience the pitfalls of going 100% SMT in your output driver circuits. Always go for as many PTH components as I can get away with after passing the initial resistance from management with their argument of it costing more due to not just being able to shove it in a pick & place machine and be done with it. I guess manufacture costing was probably a factor on this board.

Last few driver board designs I've completed all use intelligent mosfets, you just cannot blow those things up no matter how hard you try. Very difficult to find those parts in these times though unfortunately.
 
licksweets said:
I don't know what SMT driver transistor they've used here and if it had internal flyback diode back EMF dampening but I've certainly had fried drivers due to the diodes on the solenoids going weak or open circuit / dry jointed. They'll not take back EMF for long until they pop! Any further boards will also suffer the same fate until the true fault is found.

I'll confess I've used these kind of SMT mosfets in my own work but I've been an industrial PCB designer for 10+ years and know from experience the pitfalls of going 100% SMT in your output driver circuits. Always go for as many PTH components as I can get away with after passing the initial resistance from management with their argument of it costing more due to not just being able to shove it in a pick & place machine and be done with it. I guess manufacture costing was probably a factor on this board.

Last few driver board designs I've completed all use intelligent mosfets, you just cannot blow those things up no matter how hard you try. Very difficult to find those parts in these times though unfortunately.
Click to expand...

If there's one environment where mosfets can be killed no matter what the 'theory' its pinball systems!!!! Seen so many designs over the years that are supposed to be impossible to kill but they still blow up!!!
 
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