Re: low power coils with diodes

"David Gersic" <usenet_spam_trap@xxxxxxxxxxxxxxxxxxxx> wrote in message
news:dn9tui$jbh$1@xxxxxxxxxxxxxxxxxxxxx
> You're missing the diodes that need to be in the circuit to prevent this
> from
> happening. Your new TIP102s are now blown and will need to be replaced
> again.

Yeah I destroyed my only two TIP102s, so I have 30 on order from Big Daddy
;-)

The bad diode explanation makes sense, and explains why the two coils had
diodes on them -- apparently the diodes on the motherboard itself are bad --
although they passed my DMM's diode test in-circuit.

But with new (though poorly replaced) transistors, and diodes on the coils
that apparently worked at least for a while, I'm a little concerned as to
why they failed again.

Interesting that when I got the game, the coils would not fire at all. I
guess that could also have been bad transistors, but not what happened to
them when the diodes were removed from the circuit (the replacement
transistors shorted on, whereas the old bad transistors wouldn't even try to
fire the coils.)

So I'll re-replace the 102s and replace the on-board 1N4004s and hold my
breath...and report back.

Randy


.

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