johnf@sag4.ssl.berkeley.edu (John Flanagan) (05/12/89)
Netters, and especially other LUCAS board builders, First, a general question: does anybody know of a source for 86-pin card-edge connectors which fit the expansion connector? I want to build the bus terminator which has been discussed here before. Second, a LUCAS-related plea for advice. I have a 20 MHz LUCAS board (12 MHz 68020, 16 MHz 68881, 20 MHz oscillator) which has worked very well for me for the past two months, except for the past 2 weeks. The LUCAS board is mounted on an A500 motherboard, which has the A501 memory expansion card installed. About three weeks ago, the motherboard was relocated to an XT clone case, which also houses 3 of my 4 floppy drives. About two weeks ago my computer started randomly "resetting". Without a Guru, the screen suddenly goes dark grey. Then the the power light flashes about 10 times, the screen turns light grey, and then the computer resets (dark grey screen), and tries again. After a few cycles of this, the computer gives up and shuts down (dark grey screen, no lights). The keyboard usually keeps working through this until the final shut-down, to the extent that I can Ctl-A-A it into resetting again. But to restore full functionality, I have to turn the power off and then on again. This all doesn't happen with the 68000 in there. So it looks to me like the LUCAS board somehow gets into a boneheaded state, and needs to be restarted to sync up again or something. The final clue: I've found that an easy way to generate this problem is to run a disk drive for a while. Formatting a disk once or twice is pretty much guaranteed to send it over the edge. So I'm thinking that maybe putting the LUCAS board in such proximity with the drives was not a good idea, although I've tried to shield everything as much as possible. Other things I've thought of: flakey oscillator chip, overheating, failing power supply. I think I've eliminated those possibilities, but if anybody else knows better, I'd sure appreciate hearing about it. So, does this sound familiar to anyone? I'm running out of my own ideas, and would really appreciate any suggestions from people of things to check. I will make a terminator when I can find an 86-pin card-edge socket. I hate having to back to the 68000. Thanks in advance, John Flanagan Space Sciences Laboratory johnf@sag4.ssl.berkeley.edu University of California, Berkeley ...!ucbvax!sag4.ssl!johnf Berkeley, CA 94720 (415) 642-7635 John Flanagan Space Sciences Laboratory johnf@sag4.ssl.berkeley.edu University of California, Berkeley ..!ucbvax!sag4.ssl!johnf Berkeley, CA 94720 (415) 642-7635