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Everything posted by yorgle

  1. Not sure what you mean by "drive" but yes, it connects to each of the keyboard matrix lines at both 4051's.
  2. Ok, I think I understand what I need to do to make this work. I can use the 5v at the programmable encoder (when it's on) as a signal to a spdt analog switch at the 4051 to pull the inhibit pin from ground to hi; and similarly, a normally closed quad spst between pins 10-13 at the connector to disconnect the Reset, Start, Select and Option lines. I suppose I could even include a relay to kill power to the encoder whenever the Atari is powered on, eliminating the need to unplug it from my PC when using the Atari.
  3. Thanks for all the help Bryan. This is really a learning experience for me. In the present configuration, the encoder and the Atari do not share either vcc or ground. So this "inhibit pin" you mention- what does it actually do?
  4. I want to use the same keyboard for both the Atari and a separate, programmable keyboard encoder. The two systems each work independently, but because they are electrically incompatible, I need to make them invisible to each other. In other words, I need the programmable encoder to think that the keyboard isn't plugged into the Atari (even when it is). The programmable encoder reads the keyboard matrix using physical connections to the respective row and column connections at the 4051's. It works fine as long as the keyboard isn't physically connected to the Atari. On the other side of the coin, the Atari reads the keyboard just fine-- even with the programmable encoder connected-- so long as it's unpowered, so I can just use a switch to solve that issue.
  5. Thanks for the info, guys. So I'm thinking that I should be able to give the keyboard its own, dedicated power source and then replicate the hi or lo state of each line at the connector using an optical signal instead of actual connection. Cutting power to the 4051's should make the keyboard invisible. Does that make sense?
  6. Forgive my noob question here, but when a given key is pressed, what exactly shows up at the 15 pins at the keyboard connector on a 1200xl? From the schematic, I see that some of the lines are ground and +5 vdc, but what about the the lines that connect to POKEY? I believe I am just looking for combinations of volts on/off at those pins? or something more complicated? The reason I ask is that I'm trying to electrically isolate the keyboard from the motherboard and would like to use optocouplers so that no actual current passes between the keyboard and the motherboard. Any help or thoughts?
  7. I've got a couple Atari 400 or 800 (not sure which) expansion boards in my parts pile. Neither has any IC's, just empty sockets. Are these things worth anything to anyone or should I just chuck 'em. The part no. on one is C012989 REV E 1979, and the other has CA051109 REV ? in ink stamped over the top of C015500 REV 6. If anyone wants them, let me know.
  8. If you mean the case itself (not the PCB), the one I have here is 71/4 inches L x 3 3/4 inches W x 1 3/4 H. These are the overall measurements, including the "bump out" area on the bottom, but NOT including the bump out for the PBI connector. There is a 1/4 inch wide, 45 deg bevel around the outside edge, top and bottom.
  9. Back in the day, a native 80 column display would have have been all it took to set the XL line apart from the toys.
  10. I've been using my 1200xl and a CX85 numeric keypad as my primary keyboard on my work pc for a few years now. 99% of my work is text editing and numeric input into spreadsheets so there are plenty of keys available. I keep a wireless usb keyboard in a drawer for the few times I need special keys. I love having my Atari on my desk all the time.
  11. That thing takes yellowing to a whole new level.
  12. Yes. But why? It's never going to be portable unless you want to drag a monitor around and that would still need a power supply.
  13. I'm typing this right now on my 1200xl using a programmable controller that is hardwired into the keyboard matrix. But I like the joystick port idea even better.
  14. I finally got around to working on this using Candle's schematic. Here it is so far squeezed onto my tiny breadboard and I'm learning the hard way that there is an art to placement of components. Unfortunately, this is as far as I can go for now since I'm waiting on the crystal and my programmer to arrive.
  15. My workhorse 1200XL because I use it (at least it's keyboard) almost daily.
  16. I've had good results cleaning both the gold pads and the carbon pads with a soft pencil eraser- just rub the gold pads until they are shiny and the carbon pads until they are grey instead of black. Clean the eraser on a scrap of paper as you go and make sure you blow away any bits of eraser from between the mylar and the pc board before you put things back together. You can also avoid dealing with the connector issues by using a paper binding clamp over the connector and pulling the mylar back for cleaning one side at a time. When reassembling the keyboard, turn the tiny screws in until they stop and then maybe a quarter turn past that-- they don't need to be very tight at all or the pc board will warp.
  17. I dunno, 1200xl's affect you more than most. It's weird.
  18. Wow. I've been away for a good long while and just stumbled on this thread while hunting for an original .bin of my missadventure hack. Amazing bit of work there, Nukey.
  19. OK, so both of my dead units are plain old boring rev 10
  20. I went through my pile of 1200xl's and none of them display the trademark symbol. I've got two dead units so there is still a chance that one of them might hold the elusive rev 11 os. Is it possible to tell by looking at the chips?
  21. The 1050 is my CD/DVD drive and has a usb port in the spot where the power switch used to be.
  22. Sorry to veer aside from the topic, but reading that makes me feel like I just awoke from a cryogenic sleep and zillions of years have gone by.
  23. The stuff I have is called Wire Glue and is made by andersproducts.com. It's the only one I've used so I can't say if it's better or worse than others, but I can say it does work for fixing 1200xl keyboards.
  24. I think the problem with the pens is that after a few weeks, the conductive particles separate from the ink/glue/whatever and no amount of shaking will mix them back in. Last year I bought a tiny jar of conductive glue off ebay and it still works. The stuff does separate from sitting, but I just stir it up each time with a paperclip and use a fine paintbrush to apply it. The other advantage of the jar over the pens is that you can paint as wide or thin a line as you want.
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