dbstallman
Member
I just picked up my THIRD (!!) non-working Tekken Tag board. I had picked up a copule of them several years ago thinking I would be able to combine parts together to make a working one, but was only able to make them boot about 10% of the time and neither ever had any sound.
Last week I caught another one for just $10.00 figuring I would give it another shot. This board, like the others, would not boot. I had learned that the top board (CPU board) is interchangeable between the different System 12 games when working on the other two and had managed to verify that one of them was working 100% on my Soul Calibur PCB. I swapped that CPU board onto the new one and plugged it in... I was greeted with a black screen. I turned away for a second to see if I could find the other CPU board when I heard the opening movie playing! Looking back to my cabinet I still saw the black screen. I tried coining it up and the game was playing blind.
This was very promising, I now only needed to figure out why there was no video. I started by testing the RGB signal level at the JAMMA connector. All three colors were setting at a steady 1.64 volts, but the sync signal was at a proper voltage of around 3.2 volts.
I tried following the traces back to figure out where the trouble might be, but I quickly lost track of them under components and into the middle layer of the board. Not wanting to give up, I went to the MAME driver to see if I could figure out which chips were the video processors. According to the MAME driver, the RGB signal is run through a "Pre-Driver" - Sony CXA1779P. I checked the RGB outputs from that chip and found it to be the same as on the JAMMA connector, but the input signal for each color was around 3.2 volts. I tested the other pins and found the Vcc voltage was right at 5v. It took a couple of minutes looking at the datasheet before I noticed that the Vcc on that chip is supposed to be 14v.
I pulled my Soul Calibur out and verified the voltage of that chip's pin 1 and found it to be 11.8v. I was unable to determine where the break in 12v was on the Tekken board, so I just pulled it from the JAMMA connector like so :
I gave it a test and it is now working perfectly! Finally I have a working Tekken Tag (although, I have spent as much as one working board costs over the years to purchase these three
).
Now for my question : Somehow, the VRAM on this board was cleared before I got the video working (or maybe even before I got the board), is there a quick way to unlock all the time release characters? I can't even find any info on the web as to how long it takes to unlock the hidden characters, what order they unlock in, how many at a time, etc. The best I can find is just the info for unlocking in the PS2 version.
Thanks for reading my log,
Brian.
Last week I caught another one for just $10.00 figuring I would give it another shot. This board, like the others, would not boot. I had learned that the top board (CPU board) is interchangeable between the different System 12 games when working on the other two and had managed to verify that one of them was working 100% on my Soul Calibur PCB. I swapped that CPU board onto the new one and plugged it in... I was greeted with a black screen. I turned away for a second to see if I could find the other CPU board when I heard the opening movie playing! Looking back to my cabinet I still saw the black screen. I tried coining it up and the game was playing blind.
This was very promising, I now only needed to figure out why there was no video. I started by testing the RGB signal level at the JAMMA connector. All three colors were setting at a steady 1.64 volts, but the sync signal was at a proper voltage of around 3.2 volts.
I tried following the traces back to figure out where the trouble might be, but I quickly lost track of them under components and into the middle layer of the board. Not wanting to give up, I went to the MAME driver to see if I could figure out which chips were the video processors. According to the MAME driver, the RGB signal is run through a "Pre-Driver" - Sony CXA1779P. I checked the RGB outputs from that chip and found it to be the same as on the JAMMA connector, but the input signal for each color was around 3.2 volts. I tested the other pins and found the Vcc voltage was right at 5v. It took a couple of minutes looking at the datasheet before I noticed that the Vcc on that chip is supposed to be 14v.
I pulled my Soul Calibur out and verified the voltage of that chip's pin 1 and found it to be 11.8v. I was unable to determine where the break in 12v was on the Tekken board, so I just pulled it from the JAMMA connector like so :
I gave it a test and it is now working perfectly! Finally I have a working Tekken Tag (although, I have spent as much as one working board costs over the years to purchase these three
Now for my question : Somehow, the VRAM on this board was cleared before I got the video working (or maybe even before I got the board), is there a quick way to unlock all the time release characters? I can't even find any info on the web as to how long it takes to unlock the hidden characters, what order they unlock in, how many at a time, etc. The best I can find is just the info for unlocking in the PS2 version.
Thanks for reading my log,
Brian.
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