To add to Harold's post, we've been directly emailing each other, trying all the things I can think of. Here's what I know thus far.
All the SD Cards are talking back but at a 1.5V range, not the 2.5V that I measure on my board.
He verified there are no shorts on the SD Data out to the 74LS299
He replaced the 74LS299
I'm awaiting some (inexpensive) 1G SD Cards from ebay, when they come, I'll try them on my system and if working, send one to Harold. But while we are waiting, it would be interesting to hear back from other builders on their experiences with the SD card.
> Date: Thu, 30 Oct 2014 05:40:18 -0700
> From: n8vem...@googlegroups.com
> To: n8vem...@googlegroups.com
> Subject: [N8VEM-S100:5471] Problem with ALTAIR-IMSAI 8080 CPU Board
> I just finished assembly of the S-100 8080 CPU board for my ALTAIR 8800. The board appears to run great except that I can't get the SD card to initialize! I have tried several different makes of cards from 256Mb to 1Gb but no luck.
> Any ideas from those who have built this board? Any feedback would be great.
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