The latest installment to my repair journey had me flexing my troubleshooting skills to the max.
One of my clients contacted me months ago about issues with his TZ. Turns out his display was showing nothing but garbage after swapping in a ColorDMD. On top of that, the game was doing a bunch of other weird things like firing all the coils momentarily when you powered the game up, the clock was throwing "Clock Broken" errors and the flippers were so weak that when you pressed the flipper buttons they would barely make a full flip! I told him that I unfortunately didn't have time in my schedule to get up to his place, plus with the amount of issues the game was having I felt it would be best to have it in my shop to troubleshoot. Fast forward a few months and I finally had enough room in my shop to make room for delivery, so the owner brought it down.
Now, between the time he initially called me for help and the time I got my hands on the game another tech had gone through the game at his home, and unfortunately was not able to determine the cause of all the issues. This is what I was dealing with on power-up
As you can see, that just isn't right. On top of the garbled display, I had the "Clock Broken" error, I had GI in the backbox and sections of the PF slowly strobing, and in test when the flipper buttons were pressed the flippers were SUPER weak and would barely make a full flip. I decided to start with the display, as that is crutial to testing everyting else in the game.
Initially it would appear that the data from the game being sent to the display was corrupt, and the first thing you check for that is ribbon cables as it's the easiest thing to do. (all of the other issues the game had wouldn't normally be assosiated with ribbon cables) At some point all of the ribbon cables in this game had already been replaced with repro units, so the chances of it being a bad cable was remote but I did find this...
As you can see this connector was not installed correctly! This is the daisy chained cable from the MPU to the Fliptronic's PCB over to the sound PCB and then finally the DMD controller PCB. Unfortunately for me this didn't fix ANY of the issues with the display or anything else happening in the game. The next thing I tried, again just because it was easy, was swap ALL of the cables from the game out with known working ones from another game. Once again, no change. Where the game wasn't using a stock plasma DMD I wasn't sure if the display issue was with the ColorDMD assembly or not, so I swapped the ColorDMD with a stock plasma DMD.
At this point I made a little progress, as the stock DMD was finally showing correct display information but there was still an issue with it. If anyone has seen an outgassing DMD, that is the best way to describe it but I know the DMD is perfect as it came from one of my own games. On power up the display was only showing informatoin sporradically, mostly on the left side of the DMD but the longer I had the game powered up the better the image would get to the point where in test I could finally see all of the menus. Where I knew the DMD was good I suspected a failing High Voltage power supply section on the DMD controller PCB but probing it with my DMM all of the voltages were well within spec! WTF?
What we know is the DMD is good, the voltages are good and all of the ribbon cables are good. I have a spare working DMD controller PCB so I swap that into the game to eliminate that from the equation, and you guessed it... no change! So at this point I have pretty much eliminated all of the easy stuff and I need to turn my attention further up-stream.
With the DMD working enough I figured it was time to put the game through some of it's self tests. First I ran the DMD tests, which passed as I suspected it would at this point. I ran the coil tests and noticed that a bunch of the coils were not working even though all the fuses are tested good. I ran the clock test, which presented a little more information. The clock was actually working, but the clock hands were running REALLY REALLY slow which is why the game kept throwing the "Clock Broken" error. It was as if something in the game was tanking all of the 12VDC power driving the clock motor along with all of the opto's in the game. I had a bit of an A-HA moment at this point, because remember the weak flippers? TZ uses flipper opto PCB's so I realized that the flippers and the clock issue are now related, but I still didn't know how. Where all of these issues seemed to stem from the DMD, for giggles I ended up disconnecting the ribbon cable to the DMD during the clock test and wouldn't you know it the clock hands began to move at their correct speed?!? I then hit the flipper buttons and those too were now working perfect! Reconnect the DMD ribbon cable and the clock and the flippers both sh*t the bed again.
One of my clients contacted me months ago about issues with his TZ. Turns out his display was showing nothing but garbage after swapping in a ColorDMD. On top of that, the game was doing a bunch of other weird things like firing all the coils momentarily when you powered the game up, the clock was throwing "Clock Broken" errors and the flippers were so weak that when you pressed the flipper buttons they would barely make a full flip! I told him that I unfortunately didn't have time in my schedule to get up to his place, plus with the amount of issues the game was having I felt it would be best to have it in my shop to troubleshoot. Fast forward a few months and I finally had enough room in my shop to make room for delivery, so the owner brought it down.
Now, between the time he initially called me for help and the time I got my hands on the game another tech had gone through the game at his home, and unfortunately was not able to determine the cause of all the issues. This is what I was dealing with on power-up
As you can see, that just isn't right. On top of the garbled display, I had the "Clock Broken" error, I had GI in the backbox and sections of the PF slowly strobing, and in test when the flipper buttons were pressed the flippers were SUPER weak and would barely make a full flip. I decided to start with the display, as that is crutial to testing everyting else in the game.
Initially it would appear that the data from the game being sent to the display was corrupt, and the first thing you check for that is ribbon cables as it's the easiest thing to do. (all of the other issues the game had wouldn't normally be assosiated with ribbon cables) At some point all of the ribbon cables in this game had already been replaced with repro units, so the chances of it being a bad cable was remote but I did find this...
As you can see this connector was not installed correctly! This is the daisy chained cable from the MPU to the Fliptronic's PCB over to the sound PCB and then finally the DMD controller PCB. Unfortunately for me this didn't fix ANY of the issues with the display or anything else happening in the game. The next thing I tried, again just because it was easy, was swap ALL of the cables from the game out with known working ones from another game. Once again, no change. Where the game wasn't using a stock plasma DMD I wasn't sure if the display issue was with the ColorDMD assembly or not, so I swapped the ColorDMD with a stock plasma DMD.
At this point I made a little progress, as the stock DMD was finally showing correct display information but there was still an issue with it. If anyone has seen an outgassing DMD, that is the best way to describe it but I know the DMD is perfect as it came from one of my own games. On power up the display was only showing informatoin sporradically, mostly on the left side of the DMD but the longer I had the game powered up the better the image would get to the point where in test I could finally see all of the menus. Where I knew the DMD was good I suspected a failing High Voltage power supply section on the DMD controller PCB but probing it with my DMM all of the voltages were well within spec! WTF?
What we know is the DMD is good, the voltages are good and all of the ribbon cables are good. I have a spare working DMD controller PCB so I swap that into the game to eliminate that from the equation, and you guessed it... no change! So at this point I have pretty much eliminated all of the easy stuff and I need to turn my attention further up-stream.
With the DMD working enough I figured it was time to put the game through some of it's self tests. First I ran the DMD tests, which passed as I suspected it would at this point. I ran the coil tests and noticed that a bunch of the coils were not working even though all the fuses are tested good. I ran the clock test, which presented a little more information. The clock was actually working, but the clock hands were running REALLY REALLY slow which is why the game kept throwing the "Clock Broken" error. It was as if something in the game was tanking all of the 12VDC power driving the clock motor along with all of the opto's in the game. I had a bit of an A-HA moment at this point, because remember the weak flippers? TZ uses flipper opto PCB's so I realized that the flippers and the clock issue are now related, but I still didn't know how. Where all of these issues seemed to stem from the DMD, for giggles I ended up disconnecting the ribbon cable to the DMD during the clock test and wouldn't you know it the clock hands began to move at their correct speed?!? I then hit the flipper buttons and those too were now working perfect! Reconnect the DMD ribbon cable and the clock and the flippers both sh*t the bed again.
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I was amazed at how one IC on the databus that is responsible for controlling the GI could fail like this and tank the entire data-bus in the game. I proceed to play a couple games just to make sure everything was working and it played like a champ, so I tossed the ColorDMD back in and it too is now working as it should.
