JODY
Active member
One coil was burned so I replaced it. It controls the back right drop targets. The drop targets still would not work.
I traced it to a blown TIP120 transistor as well as its pre-driver transistor and resistor on the driver board. I replaced all three. Used a TIP102 for the TIP120.
At power up, the TIP102 blew immediately. Smoked and blew a hole in one side. The resistor and pre-driver transistor still check OK. I powered it off immediately.
Even if it was locked on due to a bad chip upstream would it blow immediately at power on? If not, do this point to a possible short somewhere on the playfield or something else?
I traced it to a blown TIP120 transistor as well as its pre-driver transistor and resistor on the driver board. I replaced all three. Used a TIP102 for the TIP120.
At power up, the TIP102 blew immediately. Smoked and blew a hole in one side. The resistor and pre-driver transistor still check OK. I powered it off immediately.
Even if it was locked on due to a bad chip upstream would it blow immediately at power on? If not, do this point to a possible short somewhere on the playfield or something else?
