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Title: Raymond, really need your help with track&field Post by: gonemad on October 12, 2012, 09:35:23 AM I recently acquired a dead Track & Field. Dead G07 and pcb. Monitor, no problem, up and running. PCB, a different story. Now, what I'm told about this pcb, is that it's the non-custom logic version, so the schematic I have is no good. Nothing matches. It has only the 2 boards and uses a 6809 cpu instead of the Konami custom. Powered up I get just a white screen and a hum. Probed the cpu, I have good reset and activity on the 2 clock pins. I replaced the LS245 and the 2 LS244 that are supposedly isolating the cpu. I am not sure if it's getting as far as reading the code from the program roms because if I remove the roms, it makes no change. I also put in a new OSC. I am not the swiftest try to figure out what does what, Buffers and such. I have done a ton of reading on your repair logs and others, trying to understand how things work. The tools I have on hand are solder station, probe(with audio), good DMM, Willem GQ-4X programmer. I don't have a scope, and even if I did, I would be like a monkey with wrench. Really hoping I can find someone with the patience to help me along with this. I have a feeling it's probably something simple, but I just don't have the expertise to find it. Thanks
Title: Re: Raymond, really need your help with track&field Post by: channelmaniac on October 13, 2012, 10:16:22 AM Hrmmm...
Bootleg boards can be tough to work on! There are generally no schematics and sometimes the code is different. First thing to do is to check the ROMs. Read them in and save their image to disk. Drag and drop the image file into WinROMIdent and see if it can identify the ROMs. If it can, you can use that to see if one of them is bad. Replace any bad ROMs and see if that was the problem. If it can't identify the ROMs then you will not know if you have any bad ones or not and that will suck BADLY. Next, you'll really need an oscilloscope or frequency counter to see if the clocks are the right frequency and are a nicely shaped signal. Also, if you have a dual trace oscilloscope you can check to make sure the E and Q clocks are properly phased. The 6809 CPU has some strange clocking requirements. When the /RESET signal goes high, the CPU will start accessing memory. Look for the CPU to start reading the ROMs. This means the /OE and /CE lines on the ROMs will go low for the CPU to access them, one at a time. Many systems will have one of those 2 pins tied to ground and use just one to control access. The / means the lines are "active low", which translates to "take this line to logic low condition to activate." If none of the lines are going low at the right time then you either have a problem with the CPU or a problem with the address decoding circuitry. This can be tough to diagnose - get a logic manual and look for stuck gates. RJ Title: Re: Raymond, really need your help with track&field Post by: gonemad on October 18, 2012, 07:38:58 AM This one is actually an authentic Konami board. If you look at the pictures here, you can see they are quit different. This one used the 6809 like stated above and a non-encrypted set of program roms different from the one in the mame set. I was lucky enough to have someone send me a working set from their own board. It's like Konami's own bootleg version, with no schematic. I will check some of these things and see if I can find anything that sort of sticks out. Also, the video sync does not seem to be running either.
http://www.ebay.com/itm/Track-Field-PCB-TESTED-WORKING-/250879040084?pt=LH_DefaultDomain_0&hash=item3a698e5a54 (http://www.ebay.com/itm/Track-Field-PCB-TESTED-WORKING-/250879040084?pt=LH_DefaultDomain_0&hash=item3a698e5a54) http://www.ebay.com/itm/Track-Field-PCB-TESTED-WORKING-2-/250923529460?pt=LH_DefaultDomain_0&hash=item3a6c3534f4 (http://www.ebay.com/itm/Track-Field-PCB-TESTED-WORKING-2-/250923529460?pt=LH_DefaultDomain_0&hash=item3a6c3534f4) |