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About bob1200xl

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    River Patroller

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    Placerville, CA 95667

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  1. Bob Woolley did a simple hack that allows you to hook up a PC monochrome monitor to the XEP80. I think it even got published in Atari Classics magazine. Probably in the SLCC Journal, also. Bob
  2. You probably are doing one of two things when you touch the head mechanism - slowing it down or moving the head alignment. The head should not move much unless there is slack in the mechanism. Anyway, try putting pressure on the head (gentle...) in each direction while it's trying to read. Have you tried formatting a disk? Don't worry too much about the RPMs. Just set it close to what it was. Listen to another drive and adjust the speed from that. It doesn't have to be too close. The strobe decal sets the drive to 300 RPM. Tweak down a little from there. Bob
  3. 10K is not a valid error code. I would guess that your DOS is corrupt. Can you write to a disk that has already been formatted somewhere else? Try to write data to the drive: try a different DOS. Bob
  4. I have 'many' 35 year-old diskettes that generally work just fine. Are you sure that the drive itself is OK? How does the format fail - can you read sectors on a failed disk with a sector editor like DiskWiz? Be aware of the XF551 density - it gets confused sometimes. For the most part: Old Atari disks (APX and such) are questionable. Old 3M disks are very good. HD disks will not work, no matter what. Any disk will work Double Sided. The oxide will shed on many ICD disks. Good luck. Bob
  5. OK... follow along here... You put pressure on the head mechanism and it reads about 12-14 sectors. Then stops, trying to read. If the drive is spinning too fast, you may get this. It has not read all 18 sectors, so it doesn't try to seek to the next track. With no 'load' on the spindle motor, the disk is so fast that it can't read data at all. Press on the head mech and the disk slows down so that some sectors can be read, but not all 18. Try slowing down the drive to see if you can get it to read all 18 sectors. Keep your fingers outa there - use the speed control pot. Bob
  6. KLund: Are you booting or formatting? Do I see a felt pad on the head carriage? Bob
  7. Why not just use the native m/b for a particular type? i.e. 4164s in a 1200XL or 800XL, 4116s in a 400/800. The 41256s can be run in a 1200XL or 800XL with a minor circuit change. Unless you have hundreds of chips to test, (in which case, the PBI thing sounds most feasible) just use the sockets that come with the machine - test 8 chips of a type at once. There is an Atari diagnostic cartridge out there that seems to work pretty well for testing RAM, and other stuff, for that matter. Bob
  8. I can see banding on my 35 year-old monitor. Try soldering a wire to J2-2 (ground at the DIN connector). CAREFULLY touch the wire to the ground pin of the ICs on the m/b while watching the screen. See if the banding goes away. Try the ground side of R52. If you have a scope, look at the grounds with the scope probe ground connected at the J2-2. Bob
  9. Axial caps have green bodies, axial resistors have tan/brown bodies. Color codes are the same except that the third color is pf. Brown/black/orange is .001ufd (1000 pf) - I think. Except when it's different... Vertical banding is from ground bounce on REFRESH cycles. Count the bands, should be 9 on a GR.0 screen. I don't know how to fix it. Seems like I have seen extra ground wiring added on stock machines. Maybe. Bob
  10. The XEs put out too much video. Try shunting a 68 ohm resistor to ground. Or, 100 ohms. If you have a 'real' monitor, look for a terminating switch that says something like '75 ohms' Bob
  11. I have a bunch of keystems. You might be able to drill the center out of the keycap and remove the four pieces left in. Don't drill through the top of the keycap. Use something like a 1/16" drill at low speed. Take out all the tiny screws and remove the k/b PCB. You may have to fix your k/b when you do this. PIC: Remove the old keystem by prying it up with a suitable tool - I use a pair of curved tweezers. Insert the new keystem and press the keycap onto the new stem. Put it all back together. Test each key. Good luck! Bob
  12. Huh? Lemme check.... Ya! I'm Bob Woolley! Bob
  13. Hey... Don't I know you? Welcome back! Bob
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