1450XLD Hand Drawn Schematics You will find on this page the schematic drawings I have made of my 1450XLD TONG motherboard. I find to better understand the workings of a computer such as the 1450XLD, schematics are very important. Legal mumbo jumbo: Note - the following drawings are provided to help people better understand the inner workings of the Atari 1450XLD computer. These schematics are not 100% complete. I assume no responsilbities for missing information. They are provided AS IS and are freely distributable for all to share. Now that's out the way, on to the schematics... These schematics were created through many hours of following circuit traces using an ohm meter, well lit area, magnifying glass, and data sheet diagrams of the various I.C.'s. Call me crazy, but I enjoy analyizing the work done by Atari. IMHO (humble opinion), Atari was the greatest at innovation (remember their motto: Innovative Leisure back in the 1970's) even during their final year's in business with the Jaguar (my favorite game system)!! My only regret's in life is that I never got to work at Atari and that I didn't do enough dumpster diving!! I shutter at the thought of all the innovative stuff that is buried and gone forever in the vast landfill in Sunnyvale, CA...sigh... :^{ The following links are greyscale JPEG images of schematic drawings that I drew by hand. I made the best attempt I could to make them accurate and as detailed as possible. These drawings do not cover the entire computer, but about 80-90% of the machine. The JPEG images vary in size and are in 150 dpi resolution. I had to compromise between size and image quality. Each image contains a brief legend to the type of I.C.'s used and their circuit board designator (Uxx). Click on the following link to open that schemtic in a new window. Right click to save the image to your hard drive. "dram_sch.jpg" -> Dynamic RAM circuit - 176kb "data_bus_sch.jpg" -> Data bus circuit - 192kb "mmu_1.jpg" -> MMU #1 circuit - 172kb "mmu_2.jpg" -> MMU #2 circuit - 173kb "audio_sch.jpg" -> Audio mixer/amplifier circuit - 173kb "disk_sch.jpg" -> Parallel disk drive circuit - 253kb "modem_sch.jpg" -> Modem circuit - 192kb "speech_sch.jpg" -> Speech circuit - 124kb
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