Hey there. I am fixing up a long neglected tri-zone and it is almost done (so happy and amazed). I think I am down to the last problem.

When the "N drop target" (switch 33) closes, the entire Row of switches (on the matrix, row 1) sometimes close as well. This includes the outhole, so you only get three hits on that drop target. I lifted all the diodes on every switch in that row and they all check out. There is some board damage on the small IC's next to IC11 (which I believe drive the switch matrix. Is it possible that this chip is also my problem for the row? Or should I be looking for a transistor somewhere?

I know the photos look scary, but I have good continuity everywhere the traces are supposed to go. Looks like the previous owner had a board fire and someone paid to have it repaired.

Thanks so much in advance with what I hope is this last little step in restoring a game (fingers crossed)

Edit: I forgot to mention that this board has been bulletproofed as per Vid's guide. The SCANBE's are all gone, the header between the boards has been replaced, and the faulty resistors were all beefed up. And just for completeness, I did just fix the +5V logic on this game by installing a new psu5 to replace a faulty voltage regulator. Somehow, I doubt that is the problem in this case.

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You mean just jumper the row wires to the column wires with the connectors disconnected, right? I should just take a lead from the row wires to the banded side of a diode, and then tough the non banded side to the column headers, right? I have looked for "Clay's Guide" on this but wasn't able to find it.

Thanks again for being the one to help out barakandl. I definitely owe you a beer.

So using the procedure I outlined above, I confused myself even more. I never seemed to get more than one switch to fire at the same time, but the knocker kept going off like crazy. I think that means the game thinks I was pressing the "credit button" but I don't know where that is. Unfortunately my master display is still out, so I can't see if I was adding credits or not.

Can anyone tell me if the game knocks when you add credits, and where the credit button switch is?

Also, specific to Tri Zone, is the Z O N E drop complete a physical switch somewhere?

Thanks.

Ahh, this makes sense. Thanks! Did you know that from the switch matrix? I don't see how they connect there.

OK, so now that I know that the numbering on the connector does not match the numbering on the switch matrix, things make more sense to me. My problem is definitely in the board, as when I short Row 1 and Column 5 with the connectors off, I get the same behavior as when I hit the switch on the playfield. Several switches fire, including the eject hole and the outhole. Those make sense, because they are in the same row, but that switch also seems to fire switch 35, all drops down, and so all of them reset as well.

So is this a bad 4049? Or is that solder job the problem. There are no pads left on the back of the board, but there were also no traces on the back (except two large ground plane-esque traces). If that solder job is the fault, the only way I'll be able to fix it is with jumper wires on the back of the PCB to the right pins.

Thanks for all the help so far.

So I still can't seem to figure out what's going on. The schematic I have isn't helping me much either. None of the pins on the 4049 at IC15 switch when I close game switches. Is there a way to see which switch rows should be tied to which pins on IC 15 and IC16?

Also, I'm still a bit unclear on what I should be looking for to determine that the chips may or may not be bad. Theoretically, this problem could be on either the input or the drive side, right?

So I finally got a chance to get back to work on this and I found what I thought were all the problems. It appears as though I was not getting good connectivity between the 7406 and the PIA for the Column 5 Output. So I replaced the socket that the PIA was in and now connectivity is great.

However, now when I have everything plugged in, the game won't actually start, The two LED's flash, but my blanking is low (0.11V). I did find loose wires on the jumper that carries all the ground connections, so I replaced that with a good connector, I also reseated the interconnect (which has been replaced) and tested for connectivity on every pin. I'm afraid that maybe in the process of plugging and unplugging all those connectors (has been a lot of times now) I messed something up. Any ideas on where to look first?

Feels so silly to finally get so close to a working machine only to have it fail now.

Bump from a long time ago.

I can't get the board to boot now and I'm not sure where the problem lies. I have checked and double checked for continuity on all the sockets that needed work, but now the blanking circuit is low. Is there any chance that I damaged the blanking circuit while testing things? I was going to order the parts to rebuild the blanking circuit, but that really seems like I am chasing the wrong problem. I don't have a Test Rom, but I am thinking I might need to get one...

I forgot to mention in my post from September that when the game powers on, my two test LED's flash, but then nothing else happens. If I press the test button on the board, I get no flashes or lights of any kind. I did check to make sure that the button itself is working.

At what point in the boot sequence is the PIA II (IC11)? Would an error with this chip (either physically in the chip like I fried it, or a connection issue with the surrounding circuits) prevent the game from booting?

Thanks ABH. I've been looking into a reader for a while but have been avoiding pulling the trigger. I think this project has finally convinced me.

Where do you order blanks from?

Also, the DL site I knew of for the Williams Test Rom seems to be down (Mark's Site linked to Planetary, neither have the code). Know where I can get the image?

OK, so test rom installed (Andre's) and the board won't boot. I'm following along very closely with the repair section of Mark's pinball guide.
1. Test LED confirms teh "always on" state when probing the CPU.
2. I can't check the ROM, as I don't have any other williams games readily available
3. The CPU is active on all the right pins.
4. My 5101 is not socketed, so I haven't pulled it out yet. The implied rarity of this problem made me not want to do it, but I certainly could if people think it's important
5. The address bus signal buffer at IC4 checks out good, with all pairs behaving the same, but the buffer at IC3 does indeed have a problem. Pins 6 and 7 do not have the same behavior (see my overkill demonstration video https://goo.gl/photos/3q3Cqb5LX3jJQB1V7). This seems like it needs to be replaced! I did want to make sure that there shouldn't be other issues at the same time, so I continued down the list. I hate paying for shipping more than once.
6. My board is jumpered, so this is not an issue
7. Pin 20 has activity, so selection is good.
8. Pins 2 and 3 on IC8 have pulsing activity, but average about 3.5 V with the DMM
9. Pins 13 and 14 on IC8 are also good
10. TP4 only reads 0.18 V, but if I understand correctly, this could happen because the ROM never loaded? My game doesn't boot at all, so I don't think I can say anything about the blanking circuit.

So, with all of this, I am leaning towards the bad address signal buffer at IC3. Does it seem likely that is why the game won't boot? If so, I'm trying to figure out why it would have failed in the process of fixing the switch matrix circuits on the driver board. Is it in any way related? or did taking the combination of boards in and out of the game as many times as I did just finally take it's toll on an old part?

Thanks so much for all the help so far. I Maybe now I'm one part away from a working game...

Hey Andre, thanks so much. Great to hear from you!

The board isn't quite up yet, it's still locked. I will pull all the Ram and the 5101 when I get home this evening and see if that will allow the board to boot. I do have the LED diagnostics installed, but haven't been able to get the Test Rom to boot yet.

When you mention "replaying" the PIA, do you mean I should desolder and re-install IC18 on the system 6 board? (Obviously, I would reinstall with a socket instead of soldering back to the board.)

I have the Data buffer on order in case that is in deed the problem that is preventing the board from booting the ROM (But I kind of doubt it. it seems like this problem is more likely a connection/bad trace problem on this old and previously damaged board.)

Thanks so much!

So, even with all the Ram pulled off the board, the Test Rom still won't boot. Both LED's stay lit on power up. I have ordered the data buffer, so I'll install the new one when it gets here and we'll see if the board can boot.

So I'm losing more and more faith. With all the Ram pulled, and the new hex inverter installed at IC3 (which tests out great now with the benchtop PSU and the Test Rom installed), the board still won't boot.

The CPU has activity, so at this point I'm not sure where else to look. Are there any components on the Driver board that I should be checking? Could a problem with IC11 (PIA II) on the driver board cause the cpu board to not boot?

Thanks in advance!

Thanks Andre! It seems like perhaps my image for the test rom was NOT good. The burner (and the chips) I am using is perhaps not the best, so I suspect it may have failed to write the code correctly. I went back and tried the gamer roms and the board still won't boot (Both LED's flash once, then go out, but the diagnostic button fails to produce any flashes). I burned an image of Leon's test ROM and it seems to work enough to get the LED's flashing. So I'm trying to check my game roms now, using my reader.

Both of my flipper ROMs pass checksum tests, but my two game roms (4871 and 4872 ) both test Blank with my reader! So I think I found out why the game won't boot, but now I have more issues. (Firstly, how did both of these chips get erased? That seems like an uncommon event)

I have a burner, so I figured I was going to just download the game code and burn myself a new rom, but I get conflicting information on the internet.

Online at a few different spots, people refer to the Gamerom for Tri-Zone, and suggest that it should be a single chip. I have two chips, in the PROM 1 and PROM2 spots, and no chip in IC14. Can the 2 chips be replaced by 1 single chip? Also, all I have for chips are 2732 and 2532. What chip should this game ROM be on? Online sources seem to say a 9316, but I haven't heard of that chip very often. Is there anyway I can burn the code onto a 2732 and have it work?

Thanks so much

Thanks again! What solid help. I could have probably put all that together but it would have taken me quite a while. Interestingly, my board already has jumper 3 installed instead of J4. I wonder if someone was intending to switch this before I got it and never got around to it.

I'll get the SCANBE at IC14 knocked out and report back soon.

Thank you so much! I may never know why suddenly two game roms went blank, but I have a booting system once again. Now I just have a master display to fix up, and this game is as good as new. Thanks so much for all the help from everyone!

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