ranjit@eniac.seas.upenn.edu (Ranjit Bhatnagar) (03/14/90)
For a couple of months I've been using an ancient Bare Boards RAM card plugged into my Amiga 1000 w/Hurricane 020/881. It does not autoconfigure; I had it half populated with 1 meg of 256kx1 150ns chips. It worked beautifully, no problem. Today I bought another megabyte worth of 256kx1 chips and threw 'em in the card. Now, however, the card only works intermittently, and in a weird way. I have three 1.3 kickstart disks: one normal, one patched to addmem 1M of RAM at 400000, and one patched to addmem 2M of RAM at 400000. Since installing the second meg of chips in the bareboards card, I find that booting either of the patched kickstart disks ALMOST always leads to a purple or red screen, at which hitting ctrl-A-A leads to a light gray followed by a dark gray screen. Once in a while, booting a patched kickstart gives a flickering screen, and very occasionally it boots successfully. If I boot the unpatched kickstart and then manually addmem the extra memory, either 1M or 2M, the machine gurus a few seconds later. When I am able to keep the machine alive long enough to run memory tests, they report no errors, yet the system usually gurus within a few minutes. Why this is weird: assuming any of the new RAM chips were bad, why should it cause even the old bank of RAM, which used to work perfectly, to work no longer? If one of the new chips is bad, it should lead to bit errors in the new bank. I tried pulling the new bank of RAM out, and, sure enough, the old bank worked fine. I suspected a power shortage, so I unplugged my genlock and 2nd disk drive, but it made no difference. My voltmeter reports a nice strong 5V on the RAM chips. I suspected a cold solder joint, so I resoldered the 86-pin SOTS connector, just to be sure. No difference. I swapped the buffer chips on the RAM card (5 74F04's) around. No difference. I tried running with 1.5 M (48) chips plugged in. Same as with all 64 chips. Any ideas? I'm bewildered. Occasionally - I can't say why - the thing works fine until I reboot. I'm using the first 1M bank at this moment, with the second 1M left un-addmem'ed, and it hasn't crashed yet, but who knows. Let me sum up the facts: Used to work with 1M installed and 32 empty sockets With 2M installed, any attempt to addmem either the old 1M or all 2M leads to purple screen or guru. However, if I don't attempt to use the memory, there's no problem. I took the 2nd 32 chips back out and it worked again, so I didn't blow the refresh chip or anything like that. Sometimes it works anyway, like right NOW, but fails after a reboot. I used to have problems with interactions between the Hurricane 020 card and a Comspec RAM card, but the symptoms were VERY different. I don't want to swap out the Hurricane unless it's very likely to be the culprit. Thanks for any help or suggestions you can give. I really WANT 2M, but it seems to turn the machine into a time bomb. (No, wait, that ticking noise is just the empty disk drive :-) - ranjit "Trespassers w" ranjit@eniac.seas.upenn.edu mailrus!eecae!netnews!eniac!... A woman came up to me and said "I'd like to poison your mind With wrong ideas that appeal to you, though I am not unkind."