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Showing results for tags 'schematics'.
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I booted up my Atari 2600 JR the other day, and I found that both controller ports were unresponsive to any input from the paddles or joystick. I popped it open and took a peek at the board, and there’s no visible damage. I’m using the attached schematic and a multimeter to try and find the issue. I’ve tested C20 and L3 but they both work fine. I suck at reading schematics. What components should I be focussing on to test?
Hello. I found an old Atari 2600 console clone in my basement. Seems to be broken, some parts are missing, but the chips are all OK (CPU and ROM, I guess). Therefore I'm wondering about reusing these parts somehow on a breadboard or something. But in order to do this, I need some information on these chips and their pinouts, maybe some datasheets or schematics. The chips are labeled as follows: 6591 9208A 922511 DIP-48 (two rows of 24 pins each, 48 in total) Seems to be the CPU. WB2600-4MP DIP-32 (two rows of 16 pins each, 32 in total) Seems to be the ROM. As far as I know, there was no cartridge slot, so the games must be stored on that ROM. There's an empty place on the PCB for another DIP-28 chip, the silkscreen label says "IC3 512K MASK ROM", but there is no chip there and it seems that it has never been. HD14011BP 2C26 Just four 2-input NAND gates. MC14024BCP FFES9206 Motorola chip, 7-stage ripple counter, I guess for clock division or something, since it is near the quartz resonator. The resonator is: STANDARD 17.734475 (which I guess is its frequency in MHz) I see no separate TV circuit/chip, so I guess the TV signal is generated on the main CPU somehow. Could it be that the CPU has a TV signal generator integrated in it? I can post some photos of the PCB if needed. But I hope the labels on the chips will be enough for the experts to identify them. Can anyone help me with identifying the chips and supply some descriptions of their pinouts? Perhaps some more detailed datasheets? --- I also found an old Atari 65 XE motherboard. Unfortunately it's broken in half so the chips in the middle of the board are broken as well ;/ But other chips on the edges of the board are OK, so I'll try to reuse them as well. But I'll describe that in a separate thread later.
I've scoured the web and the AA archives and I can't seem to find any schematics for the 7800 Maria. I'm referring to logic diagrams for the chip itself, not the 7800 motherboard. These do seem to exist for TIA but I can't find any for the Maria. Does anyone know if they even exist? Surely GCC must have had to conceptualize the internal logic of the chip at some point during development, right? The reason I ask is because I'm working on a hardware project for the 7800 and I've hit a point where I fear the only way to proceed forward will likely be to attempt to replace the Maria chip with an equivalent. This has already been done with TIA but I have yet to see this done with Maria. If anyone has any information at all, it would be greatly appreciated.
Hi everyone, been awhile since I've posted here. I have a Colecovision pcb I've been trying to troubleshoot. The problem is, the board is an older version and the schematics...the only schematics...I've found seem to be for a later revision. The board revision is 75743 Rev C. The daughter board is revision 75745 Rev B. The console powers on, boots, plays and has sound but no display. Upon opening the console I found that someone had done some work to the daughter board in an attempt to repair it. The problem is every time I try to follow certain traces it leads to something else in the schematics or vice-verse. I've verified voltages are good, cleaned the power switch and tested for video on pin 36 of the VPU. Even if someone can post a picture of the section with the daughter card removed might be helpful. The best would be if there are schematics for this revision but I'm not holding out hope for that Any help or advice would be great, thanks