SO I just replaced the Sound/aux board that took out a bunch of lights when it failed.... unsure about how, anyway it played ok before this last episode but now it plays but has an issue i'm trying to track down. when you hit play ball ejects for play and there is already 1K lit on the progressive lights/counter. If i just reach in and hit one of the advance actions it jumps right to 10K then repeats its count back to 1 to run to 20 if I hit it again. When ball reaches end of game play, it starts counting out the score but before it can get to zero the 10 light comes on again and it resets and just keeps counting forever and ever lol.... All playfield switches appear to work normally except as noted above and all bumpers also seem to function correctly. Anyone have any ideas?

Ok, so got the schemtics and doing a bit more troubleshooting/fault identification.... everything above still holds true.... however I have found a couple new symptoms that seem related... 1st. SW1 Toggle 7 On/Off DOES NOT change the multiplier.... I cannot seem to run the test using the test button. The Start Button appears to work ok on MM, BUT 6 out of 10 times it auto starts a game when I turn the power on.... about 4 times it doesn't and waits for the start button confirmation. I cannot seem to get the coin mech to register a credit on either left or right coin slots.... What I have done so far:

Cleaned all edge connectors, replaced the aux board with what appears to be a good one, Changed and serviced every light and checked and adjusted all switches... I do notice some "dim" bulbs in the progressive stream until they light but the connections are good. I'm pretty sure this is all MPU related in some fashion. I removed the CPU and cleaned all the legs and re-installed... no difference....

Going to try to find my 40 year old Logic Probe lol.... Going to start on that SW1-7 and see why it doesn't appear to be changing the multiple as that is a good as any place to start...

Okay fixed the symptom of it auto starting, was a bad switch... simple. I'm confused on the circuit diagrams... it shows the 2 blocks of dip swithes on the OUTPUT side of a BCD decoder? then it goes through the switches to a common side on the other with what appears to be a pull up resistor. this seems just backwards to me. what am I missing? what good does it do to tie an output of a BCD Decoder to 2 dip with blocks then all the outputs are used for a single switch but the other side is a common? like it should go somewhere else as well but I'm not seeing it? I get the BCD decoder could enable or disable one of the switches by bringing one side to a high or low, but it would need to branch off somewhere and feed that input back to the processor on an input.... I'll study them again, but I only see the one connection to the switches.

Ok, so I went back an read the manual, probably should have done that. SO they are using the Demux units to address a serial bus and monitor for all the switch decode data.... Ok, I get it now... not going to try to decode all the data as most functions seem to work. I'm now stuck on Plug J7 Pins A,1,3 The Green Wire is a common wire used to feed both the Tilt Cabinet and Self Test button. Both these functions do not work. I cannot seem to get it into self test mode. So I chased the green Pin 3 wire ( schematic is hard to read but pretty sure it is 3 since that is where the green wire is. It passes though the audio board, don't ask my why, and then over to the main board. It is an output pin of a 145 decoder chip F9 pin 2. When I monitor it with a logic probe is has noise or something, shows kinda a logic low but not really.... I think I am going to try to probe B+ and B- to see if I can send it into test mode. I'd like to see if the CPU will tell me if there is a switch decode stuck issue. the BUS that switch data rides on is a single line ( aka serial) and i would think by forcing it high or low it would be ok... wish me luck. I have some 145 chips on the way, as this chip had been soldered on before hmmmmm....... but I cleaned and removed it and all runs and pads appear in nice shape. I guess if needed, I can get my scope out to see all the data running down that line, but would prefer not to at this point. I think if I can get it in self test mode, I can make progress... What say anyone out there?

YeahI can have a look on that Ethan... I think I'm headed for pulling my scope out on this one... lol I saw in the schematic where the with is tied to one of the switches on SW2 switch 1.... FWIW, they didn't put these in order so you have to match the schematics 1-8 crossing to 16-9 unsure why, I suppose to confuse us...if that switch is open then the test never runs.... I'll double check it, but pretty sure I did.... I ordered some spare 145's since they are cheap, I"m going to shotgun in about 8 on by board, along with some of the other mix/demux stuff.... FWIW, I don't seem to get ANY switches to change.... I can't even get it to change the scoring multuplier... I did check the pull up resister R127 I think and it was fine.... the other common items on that line seem fine....

PROGRESS!!!! after getting the scope out and not being able to get any of the switches to respond to any changes.... I ordered up a 9301 AT e11 position, that is the decoder feeding all the 75145 chips and WALLA!!!! My switches now function normally!!! I can change all the dip switches and they are read and work correctly. This has allowed me to now enter the self test modes, and I tested all light and solenoid circuits and everything test A-OK!!!!

BUT my issue persist. When I hit the play button, the first progressive marker automatically lights before any play ( i would think it should light once you get a progressive score" then when I activate ANY switch that would normally count up on the progressive, the first time, it kicks up to Double bonus! then it counts to 6 and Jumps again to Tripple or whatever the next multiplier is.... it plays fine.... when ball hits end play pocket it starts to count down, but as it passes 7 down to 6 it auto lights the double and just keeps counting down then adding a double and counts forever. It is almost like there is a STUCK high bit on the bus that feeds the counter.... Gonna have to dig deep into this one.... anyone have any guesses? FWIW, I could see ALL the data on the serial line from all the 75145 chips as switch data, but toggling the switches didn't change since the decoder 9301 wasn't toggling the input lines properly I guess....