tep392 Posted December 29, 2009 Share Posted December 29, 2009 I bought a 400 and 810 drive on ebay recently and was pleasantly surprised to find a few undisclosed modifications. The 400 had an aftermarket ram expansion and the 810 drive has some kind of modified rom. I don't know what the modification does though so thought I would post a picture in hopes that someone might know what it is. The rom chip sitting off to the side has the numbers for a factory 810 rom. The side board has an eprom and a few extra wires soldered to it. Any guess about what this is? Quote Link to comment Share on other sites More sharing options...
jaybird3rd Posted December 29, 2009 Share Posted December 29, 2009 Interesting. Another member once asked about these boards in an earlier thread, and it seems that the extra board at the top (part number CO17227) is an Atari daughterboard containing the floppy controller chip and an external data separator. Apparently the early versions of the floppy chip (the 1771 you see on the daughterboard) had inadequate data separators built in, so this board was added to early 810 drives to improve their reliability. Perhaps the EPROM and jumper wires were installed as part of this upgrade. Quote Link to comment Share on other sites More sharing options...
+Larry Posted December 29, 2009 Share Posted December 29, 2009 The so-called "Grass Valley" 810 upgrade? Original 810's were unreliable to the point that people were hacking the 810's adding data separator circuits from other floppy drives. A guy in our user group had one of these hybrids, and IIRC it had a Percom or TRS data separator hacked in. When I got my first 810 in 1982, fortunately it had the upgrade. It's been a long time, but those boards look like what was in my original 810. -Larry Interesting. Another member once asked about these boards in an earlier thread, and it seems that the extra board at the top (part number CO17227) is an Atari daughterboard containing the floppy controller chip and an external data separator. Apparently the early versions of the floppy chip (the 1771 you see on the daughterboard) had inadequate data separators built in, so this board was added to early 810 drives to improve their reliability. Perhaps the EPROM and jumper wires were installed as part of this upgrade. Quote Link to comment Share on other sites More sharing options...
tep392 Posted January 31, 2010 Author Share Posted January 31, 2010 The so-called "Grass Valley" 810 upgrade? Original 810's were unreliable to the point that people were hacking the 810's adding data separator circuits from other floppy drives. A guy in our user group had one of these hybrids, and IIRC it had a Percom or TRS data separator hacked in. When I got my first 810 in 1982, fortunately it had the upgrade. It's been a long time, but those boards look like what was in my original 810. -Larry Interesting. Another member once asked about these boards in an earlier thread, and it seems that the extra board at the top (part number CO17227) is an Atari daughterboard containing the floppy controller chip and an external data separator. Apparently the early versions of the floppy chip (the 1771 you see on the daughterboard) had inadequate data separators built in, so this board was added to early 810 drives to improve their reliability. Perhaps the EPROM and jumper wires were installed as part of this upgrade. I think I have it figured out now. I found some info on the daughterboard and C version rom. They both went into production in late 1981. My drive was made in early 82 so it would have had these from the factory. The EPROM responds to the Archiver s/w and will write bad sectors while copying so I believe it is an Archiver chip. It might be a bootleg copy though. The 1966 written on the chip is the open code. Thanks for the help everyone! It's been fun and educational researching this drive. Perry Quote Link to comment Share on other sites More sharing options...
tregare Posted January 31, 2010 Share Posted January 31, 2010 Interesting. Another member once asked about these boards in an earlier thread, and it seems that the extra board at the top (part number CO17227) is an Atari daughterboard containing the floppy controller chip and an external data separator. Apparently the early versions of the floppy chip (the 1771 you see on the daughterboard) had inadequate data separators built in, so this board was added to early 810 drives to improve their reliability. Perhaps the EPROM and jumper wires were installed as part of this upgrade. even the later 1771 chips had marginal data seperation Quote Link to comment Share on other sites More sharing options...
sup8pdct Posted February 1, 2010 Share Posted February 1, 2010 (edited) I bought a 400 and 810 drive on ebay recently and was pleasantly surprised to find a few undisclosed modifications. The 400 had an aftermarket ram expansion and the 810 drive has some kind of modified rom. I don't know what the modification does though so thought I would post a picture in hopes that someone might know what it is. The rom chip sitting off to the side has the numbers for a factory 810 rom. The side board has an eprom and a few extra wires soldered to it. Any guess about what this is? please ignore Edited February 1, 2010 by sup8pdct Quote Link to comment Share on other sites More sharing options...
+Stephen Posted January 3 Share Posted January 3 On 2/1/2010 at 7:26 AM, sup8pdct said: please ignore We're doing that over here now. 4 Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted January 17 Share Posted January 17 all such deleted/please ignore messages should be moved to the ignore thread !!! Quote Link to comment Share on other sites More sharing options...
deffroe Posted January 17 Share Posted January 17 9 hours ago, _The Doctor__ said: all such deleted/please ignore messages should be moved to the ignore thread !!! That's a good idea but bet you it gets ignored!!! 1 Quote Link to comment Share on other sites More sharing options...
tep392 Posted January 19 Author Share Posted January 19 On 1/17/2024 at 11:44 AM, deffroe said: That's a good idea but bet you it gets ignored!!! Already has been. Quote Link to comment Share on other sites More sharing options...
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