Hi there, I've analyzed the RAM problem on my Fat40 a bit more. I've recorded the broken addresses - which are stable - and measured the RAM chip in question (UA16 ) with the scope. See https://www.flickr.com/photos/afachat/sets/72157646409152698/ What looks interesting is that the data I/O pins of the RAM even stays high when I write a zero into it! I.e. either the RAM is broken and pulls the line high, or the driver (or something else) is broken. However, I cannot see why the combination of address bits should create a driver failure. Measuring another chip in the same bank shows the corresponding data line going low as it should, as well as the same chip with another address. Anyway, I've ordered a 4116 RAM replacement and will replace the chip to see how it works out. André Message was sent through the cbm-hackers mailing listReceived on 2014-08-28 23:00:02
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