I have been working on a Laser Cue - Williams System 7 - pinball game. When I got it there were a lot of problems. I removed the boards and resoldered the pins and replaced some resistors and transistors that were bad. When I put the boards back in and turned the game on, The Lower Bumper - Solenoid 18 - would immediately lock on and the game would not boot. I removed fuse F2 and restarted the game.
Now the game would start and boot up. The GI lights on the playfield and backbox worked. The lights on the playfield that blink did not work at all. The ball did not kick out to the plunger but I assume that is because the solenoid fuse is out. All of the targets, rollovers and spinners scored properly. When I looked at the Driver Board - I noticed that the 8 large resistors in the lower right corner - R149-R156 - were real real hot. I stopped the game and removed the Driver Board. I noticed that the solder that was holding these resistors on had started to melt. I am showing some pictures of the Driver Board (Resistors R149-R156 are the large white resistors). The area where these resistors are had some previous burning damage but I had these blinking lights working before I removed the boards to work on them.
Anyone have any idea why the blinking lights would not work and why these resistors would get so hot? Also any idea why the bumper solenoid would lock on - The switch under the bumper is open? I did not do any work to this bumper but I did change the bumper skirt on the right bumper. I just replaced the Q4 TIP122 Transistor when I took the board out but I have not tested this yet to see if it solved the bumper solenoid issue - I doubt it.
Thank you.

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Doing a lot of reading on Williams System 7 and it appears as though those HOT resistors on my game are a common problem and a potential fire waiting to happen. There appear to be several possible fixes for this issue and I have to figure out which one I will do. Now my remaining 2 issues:
1. The playfield attract lights do not work - None of them work. The GI lights in the backbox and playfield do work. Can someone direct me to a connection or a part of the power supply that I should be focusing on to fix this problem? When I turn the game off some of these attract lights will light up very briefly before the game shuts down. I do this with the solenoid fuse out of the game.
2. The bottom bumper - solenoid 18 - locks on as soon as the game is turned on. I replaced the Q4 transistor and that did not fix the problem. I have taken this bumper apart and can confirm that the switch is open. I have not done anything else to this bumper other than clean it. Could I have touched something while cleaning it that would make it lock on?
Any help is appreciated.

I have put all new caps on the power supply. And I have replaced and checked the fuses on the power supply. Is there a fuse that only works the playfield/attract lights? Which connector would you suggest looking at? I do not have the full schematics and having a little trouble finding a printable set on the internet. As for the Driver Board....I have had it apart and checked all the resistors, resoldered all the pins and replaced some of the transistors. Is there a particular part of the Driver Board that I should be looking at? Thanks.

Thank you. That is what I needed. Now need to figure out how to check for these voltages.

Started the machine. Took off connector 3J4 from the Power Supply and checked the DC voltages from the pins on the Power Supply Board. These were my readings - Pin 1 is at the bottom and Pin 12 is at the top of the connector as it sits on the Power Supply Board:
12.....- 36.8
11.....- 36.7
10.....- 36.7
9......- 36.8
8........ 18.9
7........ 18.9
6........ 18.9
5........ 18.9
4......- 36.9
3......- 36.9
2......- 36.9
1......- 36.9

Now I must say I do not know what this means but I assume it means there is plenty of power leaving the Power Supply. Do I now plug in the 3J4 connector and check the power at the Driver Board?

Just pulled off connector 2J4 from the Driver Board. I checked all the wired connectors on 2J4 and found they all were getting 19.14 volts - DC.

Just checked the 2 bridge rectifiers below the Power Supply Board. The BR on the right measured at .491 on each of the legs adjacent to the + and - legs. The BR on the left measured at .501 on each of the legs adjacent to the + and - legs. I believe this means that these rectifiers are working properly. So the correct power is going from the Power Supply and is getting to the Driver Board. Therefore, I assume the problem is somewhere on the Driver Board - But I am really not sure about that one.

Thanks. For now I am trying to get the controlled lights to work since I think this is the easier problem to fix. When I start the machine (with the solenoid fuse out) - All 4 scores go to 0,000,000 for less than a second - Then it goes into audit mode and 2520 2 comes up in the left top score. I can cycle through and set 04 18 to 00 - for free play - When I get to 04 50 - The game does go into start mode and when I hit the start button I can score points with my fingers hitting the targets and the game will stop after 3 balls go into the trough. The match score comes up and the top left score goes to 00. When I shut the machine off - the playfield controlled lights that will not come on - flash on momentarily then the machine shuts off. So I think I know that there is proper power going to these lights because they do flash on. But I can not figure out why the game does not know to put them on when audit mode is over.

When I replaced the transistors, I also replaced the pre-driver transistors. I checked the IC chips and replaced IC6 because it had some weird readings (Higher than 700). All the other chips and resistors tested ok. I did not check the other transistors because I was not sure how to do it - But now I think I will and can do that tonight. I also need to check the transistors in that burnt area on the Driver Board. I wonder if it is possible the problem is in the Memory Protect section of the CPU Board in the area near IJ3 and IJ4.

I changed to this thread because the heading on the other one was not quite right for the lights and solenoid issues. I really appreciate the help.

I just started the game with connector 2J12 - the output to the bumper solenoid - unplugged and the bumper coil did not lock on. I assume that means that the problem is in the Driver Board since I now know that it is the output from the Driver Board that is causing the problem. Do I have that right?

I just started the game with connector 2J13 - Special Switch Inputs - unplugged and the coil did lock on. So based on this - I think the problems are definitely in the Driver Board....But I am far from an expert on this stuff.

I just checked all of the Transistors on the Driver Board and they all checked out good. Seems like the only thing to check out now is the IC chips.

Going through and checking all the IC chips on the Driver Board. I replaced chip IC6 and put in a socket. When I check the pins on this IC - Pin 1 when it is in the socket reads .250 when doing a diode check....When this chip is not in the socket - Pin 1 measures .700. All the other Pins read between .580 and .700. Does this mean I have a bad socket? IC6 Pin 1 is connected to Transistor Q2.

I have checked everything that is checkable on that Driver Board. All the resistors and transistors and IC chips. The only thing I have not done is replace the PIA chips. Could they be causing the problem?

Question: It appears to me as though all the controlled lights go through PIA III (IC10) - Lamp Matrix. PIA III is the same chip as PIA II (IC11) - Switch Matrix - which I believe works because the switches on the playfield seem to work. Can I take PIA II out and move it to PIA III and then turn the game on and if the controlled lights work - I can assume that PIA III is the issue. Not sure I have any other way of checking PIA III.

Thanks. Yeah....Not comfortable working with the logic probe since the power has to be on. Doing the best I can with what I have and can do. Easy thing to do is to send it out to someone who may or may not know how to fix the problem. Unfortunately, I am never one to take the easy route. Just trying to find out if what I want to do will work or not.

Thank you!!! Yes....PIA was socketed. Replaced the Lamp Matrix PIA chip - that measured as bad - out with the Solenoid PIA chip - that measured working - and....Amazingly the controlled lights all work as you can see. The game still starts out in audit mode and will not save any of the settings that I make. I have to think this has to do with the battery holder - which is the original - and the game is not holding the changes when the game is shut off. I think the best think to do is to replace IC19 - 5101 CMOS RAM - with an NVRAM chip and eliminate the batteries. Anyone know where the best place to get that would be. I see several online but they seem to all require some extra soldering work which I would like to avoid. My IC19 chip is already socketed.

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Just ordered one so it should be here next week. Now the only problem left would be that solenoid locking on. As I look at the Logic Diagram. The main transistor is Q4 - which I replaced and tests good - also transistor Q3 which I replaced and tests good. Then it hits IC8 pins 11, 12 13 which I did not replace but which tests good. Then it hits IC6 pins 8, 9, 10 which I did replace and which tests good. Resistors R10, R11, R12 all test good also - Although Resistor R12 tests at 2.0k ohm and not 2.7k ohm but all the similar resistors - R9, R15, R18 - test the same. Not sure what else could be causing the problem.

Thanks Xenon75. I have replaced the 2 transistors - Q4 and Q3 - associated with the bumper that is locking on, I have replaced IC6 and IC8 (They both tested a little off on some of the pins), I replaced the Lamp PIA to get the lights working, I think the solenoid PIA is ok but I have a replacement if it is not. I am replacing the coil and diode on the left kicker which was the original issue - it seems a little fried (I might have done that) and the sleeve would not move inside it. The bumper coil - which was locking on - tests ok and looks good but I am replacing the diode on it. Everything else looks good. The switch on the bumper looks good but I will check that resistor. I replaced the capacitors on the Power Supply and some on the Sound Board. I have removed the battery pack and am waiting for the NVRAM. Once the NVRAM and new coil come in, I am going to put in the solenoid fuse and start it up. Hopefully I will get more of it working. I will update on Friday.

I did everything and tested everything that I could to all the boards. I put in the new 5101 NVRAM and removed the batteries. Replaced everything that tested bad. I redid the solenoids under the playfield that were not working properly. I plugged it in and turned the game on and....the GI lights came on and the Display for the Diagnostic on the CPU Board flashes 0 twice quickly and then some of the playfield lights flash quickly and the Diagnostic Display goes out. Nothing works on the Backbox displays. Any suggestions would be appreciated.

Thanks. No the solenoid is not locking on but I also can not get the game to start so I can check if all the special solenoids are working. I replaced the Lamp PIA after I swapped it for the good solenoid PIA - I think I will try putting them back the way they were and just replacing the bad one. Funny you should ask about the Blanking issue - I swapped the IC23 chip in the Blanking section of the CPU (Because I got what I thought was a bad reading with my DMM on the original chip) - But I swapped an MC1455P1 timer with an MC1455 that I got from Marco. Do you think there is a difference between an MC1455 and an MC1455P1? I need to check the blanking signal But not sure exactly how to do it.

Plugged the game in this morning and turned it on with the coin door and backbox closed. The GI lights came on, nothing came on on the displays, the playfield lights did not go on. When I opened the backbox - the number 2 was on the Diagnostic display on the CPU. This means an error with the chip IC 16 Ram. I have read some things about this diagnostic that it should only be used with the backbox and/or coin door open. Is the reading I got with the coin door and backbox closed - 2 - a real diagnostic?

Did not touch anything else in the blanking section. Used a DMM to test the IC23 chip and got a 0.00 reading on one of the pins - probably not a good testing procedure. I just turned it on and got the GI lights to go on, some of the playfield lights went on and the displays were all 0's but very weak. Could not adjust any of the audits. When I checked TP4 with a DMM set to DC I got 3.62 volts.

I am trying to recheck all of my power supplies. I just started the game and removed connector 3J4 from the Power Supply and these were my readings:

Pins 9-12 -21.8
Pins 5-8 18.8
Pins 1-4 -21.8

When I did this previously (12 days ago) I had readings of -36.8 for pins 1-4 and 9-12. Clearly something has changed. What? What would cause these voltages to be down so dramatically and could that be causing the problem with the game not starting? Thank you.

As best I can tell this is that connector. Does the fact that Pins 1-4 and 9-12 are ground have any impact on the fact that the numbers have changed?

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Just went down and started the machine again. This time the GI lights came on, No playfield lights, No displays and the Diagnostic Display went to 0 and stayed at 0. All fuses are good. My feeling is it has to be the Blanking section. Tempted to take out the new IC23 and put back the old IC23. With the game on I checked TP4 - the blanking TP - and it registered 143 DC volts. I am assuming this means that there is too much voltage and the Blanking is shutting down the machine. Is that right? And what could be causing that much voltage at TP4? Thanks for any help.

I think you are right. Might be time to figure out if it is the driver board or CPU board and get a new one of those. I think there is a way to do that by starting the game with the driver board out of the machine.

Hmmm...So I just checked the NE555 chip that I replaced. Checked it by putting my positive lead on the ground - Pin 1 - and checking the the other pins with the black lead and the DMM on diode mode. I got a reading of .720 on Pin 4 of my 2 new "good" chips and I got .100 on Pin 4 of the chip now in the machine. According to the database - Pin 4 is the Reset - active low reset input forces output and discharge low. Also I got a reading of .233 on Pin 8 instead of a reading of .620 on the "good" chips. Pin 8 is Vcc - input supply voltage, 4.5v to 16v. Could that chip be the problem...or one of the problems?

I just pulled out the Driver Board, plugged in the machine and turned it on. The Diagnostic Display went to 0 immediately and stayed solid at 0 - No flashing at all. I believe this means that the problem is with the CPU because if the CPU was good - The 0 would have been flashing. Am I correct with this? All the troubleshooting guides only talk about doing this with the 2 lights on the CPU - not the display - which would be flashing and looking for the Driver Board if the CPU was good.

Thank you. Is there a somewhat simple way to tell if the problem is the Driver Board or the CPU?

Yeah I have read that so many times. Bottom line with that article…If your System 7 locks up - Go get a new CPU because it will be a miracle if you find the cause.

I know it can be done. And I certainly admire and respect anyone who can do it...I just might not have the talent and tools required to go through all the necessary steps. As for what I did - Everyone who has done it knows it is very hard to fix a game that has been sitting for 15 years. Sometimes when you get things working that haven't worked in a long time - other things break.

But talking about work that I did that may have caused a problem. When I was replacing the large capacitor - C10 - on the power supply, I spilled a small piece of solder - maybe 1/8" x 1/4" on the capacitor. I left it because I was not sure I could remove it. I did not think much of it but maybe that is causing some problems. When I just checked that capacitor with my DMM - I did not get a reading. Any thoughts on that screw up/

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