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mark66j
April 25th, 2010, 10:28 AM
It's on eBay now, and the seller is not sure what it is, and I'm curious:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150435127111

I'm bidding on it for the heck of it, but it might be more use to someone else depending on what it is.

Bobthearch
April 25th, 2010, 12:08 PM
Third party SCSI card?

wmmullaney
April 25th, 2010, 01:37 PM
Third party SCSI card?

More likely a simple I/O adapter, with the 6522s

Chuck(G)
April 25th, 2010, 01:57 PM
I'm with Wmm--most likely a digital I/O card, particularly seeing the 6 opto-isolators. John Bell Engineering made a lot of stuff like this.

wmmullaney
April 25th, 2010, 03:21 PM
Out of curiosity, did you win it Mark?

mark66j
April 25th, 2010, 03:48 PM
Out of curiosity, did you win it Mark?

Yes, I did. I'll try to post some more detailed photos when I get it.

mark66j
May 1st, 2010, 04:21 AM
Here's a photo of the front of the board. No manufacturer's markings or numbers on either the front or back of the board!

http://www.3cat.com/images/Apple_II_mystery_board.jpg

tcpaehart
May 2nd, 2010, 01:49 AM
The 6522 was an i/o chip used in some 8 bit computers. It was used in the Commodore Pet to do the i/o for the parallel port.

The chip has, if I remember correctly, 2 8 bit i/o ports and a 16 bit shift register.

It was difficult to interface to the Apple by itself because Apple didn't put a correct phase 2 clock line on the bus.

You had to take the phase 0 line and run it thru 2 gates to delay it to get the correct timing.

John Bell Engineering made a 6522 card for the Apple that used that technique.

Or you could find the phase 2 line on the motherboard and run a jumper to the card to provide it.