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1200XL only tests 34K or RAM then restarts ROM/RAM test


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Another 1200XL troubleshooting problem. In self test, the ROM checks out and it runs through two complete rows and two blocks on row 3 three (i.e. 34K) and restarts the ROM/RAM test as if everything was good. No errors shown. Even 16K games don't load. I just re-modified the ROM from 28 pin back to 24 pin for the OS ROM. I removed R11, R12 and R13 and returned back R6, R7, R8 and R9. I get the Atari banner, so the ROM works. Did I possibly get some solder touching an adjacent pad that is screwing up the addressing or do I have possible bad RAM?

Edited by ACML
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Solved my own problem. I knew if I didn't look at the solder work I did earlier today, I'd be thinking about it Monday. Sure enough, as I suspected, I had a tiny solder overlap and it was shorting two address pins together. A little solder wick and viola!

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