DavidMil Posted July 7, 2017 Share Posted July 7, 2017 I found another mystery board mixed in with all the other Atari stuff in my attic yesterday. I'm wondering if this may be something for an ST but with the dual 13 pin SIO connectors, I'm miffed. It has a 6809 processor and a 17 pin dual pin dual connector as well as a four pin Molex connector (see pics). One complete row of the 17 pin connector is tied to ground as well as pins 4 and 6 on the SIO connector. The board also has two 7805 (5V) regulators and a 7812 (12V) regulator. One 7805 and the 7812 regulators supply the Molex connector. The other 7805 supplies the rest of the board. The EPROM window is covered with a sticker that has AT88 V. 1.3 The three large chips have the following designation's: 40 Pin F68A09P 40 pin F6821P 24 PIN F6850P I'm open for suggestions... DavidMil 2 Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted July 7, 2017 Share Posted July 7, 2017 (edited) Percom AT88-S1PD board... Edited July 7, 2017 by AtariGeezer 1 Quote Link to comment Share on other sites More sharing options...
+Nezgar Posted July 7, 2017 Share Posted July 7, 2017 (edited) Looks like the controller board from a Percom AT88 - SS SD drive. 40pin connector for standard floppy drives.. Wonder if it works, was replaced as defective, or upgraded to a double density/double sided controller in whatever drive box it came out of... Review here: http://www.atarimagazines.com/v2n8/productreviews.html And according to: http://www.atarimagazines.com/hi-res/v1n2/previews.php "The Percom "Doubler" requires no special tools to install and doubles the storage capacity of the AT88 from Atari. The retail price is $169.95. Percom also released its new family of double-density disk drives containing a parallel printer port. With these drives, you can attach a parallel printer to your Atari while by-passing the 850 Interface Module. The AT88-S1-PD is a single drive that retails for $529. The AT88-S2-PD is a double-drive that retails for $829." Picture i found: Edited July 7, 2017 by Nezgar 3 Quote Link to comment Share on other sites More sharing options...
RodLightning Posted July 7, 2017 Share Posted July 7, 2017 Very cool find. I have a working AT88 and it's my favorite floppy drive. That board will run a standard IBM 5.25in mech. The regulators along the edge screwed directly into the enclosure and use it as a heat sink. I had to replace a 7805 that broke off from the stress of pulling the SIO cable in and out. A weak point in design for sure, but still a nifty piece of hardware. 2 Quote Link to comment Share on other sites More sharing options...
DavidMil Posted July 9, 2017 Author Share Posted July 9, 2017 Looks like the controller board from a Percom AT88 - SS SD drive. 40pin connector for standard floppy drives.. Wonder if it works, was replaced as defective, or upgraded to a double density/double sided controller in whatever drive box it came out of... I think it was replaced with another board. If you look closely at the left side SIO connector you can see that pin 12 is missing. I don't suppose anyone has any schematics? DaviMil Quote Link to comment Share on other sites More sharing options...
Kyle22 Posted July 9, 2017 Share Posted July 9, 2017 Pin 12 is +12V output. It's not used by most peripherals. Quote Link to comment Share on other sites More sharing options...
DavidMil Posted July 9, 2017 Author Share Posted July 9, 2017 Very cool find. I have a working AT88 and it's my favorite floppy drive. That board will run a standard IBM 5.25in mech. There was also an old IBM 1/2 height, black face drive in the plastic container and I was wondering why it was in with the Atari stuff. Maybe if I keep digging around up there I'll find the rest of the Percom unit?. Worth a try... Thanks everyone for your knowledge! DavidMil 2 Quote Link to comment Share on other sites More sharing options...
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