Hey all,
Working on a Rescue 911 that continues to blow the switch matrix fuse. F6. Having eliminated the driver board connectors, the fuse now holds. Tells me the problem is on the playfield. However I'm trying to narrow the short, or what kind it could be. Any guidance would be great. As we cannot seem to actually step through test menus at this moment. I have my DMM out. Wondering if there is a way to test line voltages and look for a spike? A3P3 and P4 are pulled from the driver board and the fuse holds. Does this point to the playfield? Or is the Board still in question? Thanks.

Hey Guys,
Thanks for the info. Put a new filter cap in along with a bridge rectifier. Fuse continued to blow. For some background the fuse was blowing at startup. Pulled the lamp strobe in and the switch strobe in to the rectifier board. Fuse held. Put both in one after the other while cycling the power. Finally decided to put in a new ribbon cable between the driver board and the mpu board. Cleared the issue up. Don't necessarily know what the issue could be or continue to be. The game has seen better days, but I've cleaned up the wiring. Now its just a burnt out C relay on the play field and figuring out why the half the coils aren't firing. Hopefully this can help someone else.

(update) Yea so trying to update this repair as I go. Maybe help someone out. I've replaced the ribbon cable that joins the driver board and the MPU. That seemed to clear up the blowing of fuse F6. Now I'm tracking a problem of playfield fuse F30 (the back subway lift solenoid) fires on startup then blows the fuse. Also in solenoid test only half of the solenoids fire, flippers do not fire. Checked fuses, and other than F30 they all seem fine. Starting to suspect the driver board possibly. Seems odd so much would be out however. Traced solenoid power, all the power lines seem fine. Any other tests I can try? Its a pretty beat up game externally, but the playfield is great, 9 outta 10. Got it for a system 80 trade, and revived it from the dead. I feel like I'm close.

Alright, after running through the line for solder issues I got lucky, and had a buddy sell me a box of old gottlieb system 3 baords. Swapped in a driver board from my working Street Fighter and that solved the blowing of Fuse F30. So I've begun to track down the transistor on the original board to solve that problem. Still missing the lower half solenoid firings however. Including flippers. They work to drive the test menu, but nothing in game or in solenoid test. I'll get a list and postion for the solenoids that are out when my replacement manual comes in later this week. (Had to order one)
Maybe an under playfield board is the culprit.

Hello all. Another update. So after poking around I found that during solenoid test the "Q" relay in the bottom of the Cab is not engaging. I've finally my manual in and starting to pour through it. Is there a controlling transistor on the driver board for this relay? It obviously must have a control circuit somewhere, I'd love a bit of guidance on the theory of how the relay works as far as controlling a certain number, but not all the playfield solenoids. Or does it, but somehow others are working? Seems like the few solenoids near the back of the playfield work, while others near the front don't. Thanks in advance.

Alright. So after really going over the (A3) driver board, I found 6 transistors that were completely blown or out of tolerance. So after a rebuild all the solenoids are firing now! Still working on the optical switches. None of them are working either. So on to that next.

Hey, Thanks for the help so far. So after running through the schematics and looking over in test, I found several control lamps were out as well as a couple of non optical switches. Began to pour through the play field and fix those issues. None of the optical switches work still. I have one dim diode on one of the A25 boards lit dully but that is it. seems odd both boards would be out at the same time however. And not a single one of the 8 optical switches they control are working. Sadly my Tee'd off doesn't have one of these boards, so I'm going to look in my SF2 and see if there is the chance it uses one of these. I've checked the resistor board as well and it seems fine. May pull it and begin ohming resistors. Seems odd I'm getting nothing however. Any further guidance on testing would be great. Do the boards work in circut? From the schematic it seems one can work without the other.

Bingo, you found it. Thanks man. Yea the 5v line seems to have massive oscillation, between 3 and 7 volts. Somewhere the 5volt playfield line must have gotten crossed with a lamp strobe somewhere. I ran it back as far as I could found a clean 5v signal and ran a new line. Bingo. Now everything on the playfield works. Back to the driver board as Q2 and Q3 keep blowing. Checked the coils, guessing its a voltage regulator further up the board. But after that... this rough guy will finally liiiive again!!!!!

Alright, so this game still has me running in circles. It seems the smaller dioded flipper board seems to be out. Replaced the two PnP transistors and it worked for a few minutes. Then after entering the solenoid test the board goes out again. Suspecting a short. Just don't know where. Any ideas would be appreciated.