System 11 sling always energised.

[Goingpinsane]

Need some help guys. My tomcat left sling fired up on start up and stayed on. I've checked a few things. Transistor. It was bad. Replaced it. Still locked on. Checked diode-good. Both switches are open. Is there something I'm missing or could it be something else?
Cheers

[Goingpinsane]

Sorry I forgot to say the right sling has been firing on start up for a little while but doesn't lock on. Maybe connected or just coincidence?

[Strangeways]

Check the resistance of the coil. Sounds like a bad diode on the coil.

[Goingpinsane]

Is  that for the locked coil or the one that quickly fires at start up? Is the start up coil fire normal?

[Strangeways]

Is  that for the locked coil or the one that quickly fires at start up? Is the start up coil fire normal?

Locked coil. The misfiring coil will be a different issue (I think).

[Goingpinsane]

I'm a bit lost with it now. Pop bumper not working at all now as well. Could it be an issue with the board. Transistor for the left sling has gone again. Any advice on where I should start looking? I tested coils and fine. Diodes fine. Disconected special solenoid switch connector and was still energised until tranny gave up. So I guess it's not a closed switch. Could it be a bad chip or something on board? Thanks in advance for any help.

[Retropin]

If you've tested components from the transistor to sling and all is OK then it must be back to the board. There will be a "buffer" chip between main logic chip and transistor.. its there to protect the main chip. Im not familiar with sys11 games but preceding SS games always have this feature in place ( normally a 7407, 5407 or similar). That's where I would be looking next... it may well have more than one transistor fed by its gates.
Dig out those schematics!