The Sorcerer I acquired earlier this Summer is coming along nicely; however, I have two tech problems that have yet to be resolved. I am hoping that someone with more experience than myself might nudge me in the right direction.

The first issue is the right jet-bumper. Contact with the switch will score points, but the coil will not fire. If I apply ground to Q83 the coil fires fine. Is this a bad transistor at Q83, or is it upstream from there? I’m not sure what to try next.

Issue number two is with the two flashers in the center island with the Sorcerer bank. They will light up at power on and stay lit. When I run the solenoid test, they will flash slightly brighter, but not turn off. All of the other flashers are performing as expected. I have removed these two bulbs for the time being.

I’d welcome any suggestions.

Where is the pre-driver in relation to the transistor?

The flashers are 63's. The previous owner had installed a few LED's under some inserts in the lower playfield, but it's mostly still incandescents.

I'm getting resistance on Q83. I'm assuming that Q82 is the little pre-driver. I'm getting .5 on one leg, but only .2 on the other. Is it shot?

Thanks for the tips. I'll check the surrounding transistors for a benchmark reading, and take a closer look at the schematics.

Q82 is indeed attached to Q83. .2 was lower than the others I checked. The schematic has it as a 2N4401, and I see Great Plains stocks them. Should I still replace Q83 with a TIP102 even though it doesn't read as open?

Back to the flashers. I'm guessing you asked about LED's because the sockets have a trickle charge to keep the bulbs warm and ready, which could be enough juice to light the LED continuously. Why would the incandescents stay lit?

The TIP102 at Q83 (jet-bumper) read .5 on one side and .07 on the other. The TIP102 at Q41 (flashers) read .5 on one side and .03 on the other. The pre-driver for Q41 is Q72. I did not bother with a reading here as I will proactively replace it per your suggestion. I have an order in with GPE and will post an update once I am able to replace the transistors. Many thanks Vid, for taking the time to walk me through this.

Update:
I received my order from GPE and spent some time with the Sorcerer yesterday. With the MPU out of the machine and on the workbench, I could clearly see a cracked solder joint on the middle pin of Q41 (flashers). I probably could have gotten by with just re-flowing the joint, but I went ahead and replaced it and its pre-driver at Q72 anyway, along with Q83 and Q82 (jet-bumper).

With the board still on the bench, I took readings on each of the newly installed transistors using the steps outlined by Vid. Everything was within spec. I restored the MPU, replaced the flasher bulbs in the Sorcerer bank, and put the machine into solenoid test mode. The good news: the flashers are now working as expected. The bad news: the right jet-bumper is still out of commission, furthermore, the newly installed TIP102 at Q83 that read within spec on the workbench now reads .5 on one lead and .049 on the other.

The schematic shows U6, a 7402, as upstream from Q83 and Q82. Could a problem here be killing the transistors?

The coil looks brand new. I get 4.8 ohms at the coil lugs, which is the same as the other jet-bumper coil. I had replaced the diode before starting this thread. Should I cut it and test anyway? I had assumed that since the coil fires when applying ground to Q83 that things were good downstream from there.