I may have found another contributing factor to the Bad Sector trouble that has been occurring lately on my 8080 CPM machine. I have two 8" drives, A: is a Siemens FDD-100 which is the last drive on the cable and B: is a Shugart 800, which is in the middle of the cable. After finding a intermittent short in the chip select of my 8259 PIC and repairing it, I have still gotten a few (maybe three) over the past week, Bad Sector errors. I actually had bad sectors on the disk as attested by ANADISK. I had the two drives set up with the terminating resistors in place on the Siemens and the jumpers out on the Shugart. But yesterday I found that the WRITE and WRITE GATE were not going high enough for the Shugart to write consistently, hence the sector errors. The Siemens uses a resistor network for pull ups. A two resistor network of a 200 ohm and a 330 ohm resistor in series. The 220 is tied to the +5 and the 330 to ground, the pull up is in the center. The Shugart uses 150 ohm resistors tied to the +5v. So, I installed a couple pull up jumpers in the Shugart and have not had a bad Sector error since. Has anyone else tried to use two different drive manufactures like this, with similar trouble? I'm wondering if I should get another drive that matches, maybe I'd have less trouble. Mike
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