Linards Ticmanis wrote:
Michael J. Mahon wrote:I'm currently having trouble with a Softcard, a 1:1 clone of the Microsoft design, it seems.The card works well in a IIe, but fails to work in a II+. The symptom is random crashes during or shortly after I boot CP/M 2.23. The card doesn't seem to disturb normal 6502 operation though.I tried pulling all cards except for the Sofcared and one Disk II controller. No improvement.Unfortunately I don't own a second II+ and/or a second Softcard to test.What do you think? Is this likely to be some problem on the II+ mainboard, or is the card likely to be at fault?Interesting... The original SoftCard is supposed to be flakey in a //e (and, of course, work reliably in a ][ or ][+). The SoftCard uses several features of an Apple II that are not often used in other cards (like DMA), so it may be exercising things that don't work on your ][+. Unfortunately, it will take either serious work with a 'scope and/or logic analyzer or several parts substitutions to localize the problem. (You have tried "skootching" all the socketed chips up and reseating them, right?)Ok, thanks, yes I tried reseating the chips. I'll take a hard look at the schematic then.If anybody else has an idea, I should add that this is a Rev. 7 (but pre-RFI) motherboard.
My homemade Softcard clone worked fine in my Rev. 7 ][+ back in 1983. That was the "design center" for the Softcard. -michael Music synthesis for 8-bit Apple II's! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it is seriously underused."