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techknight

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  1. techknight

    I saved 100+ iBook G3 Clamshells

    He was giving them away with contests awhile back. its possible he gave them all away.
  2. techknight

    SCSI to Ethernet Adapter on New Hardware

    I actually use the ATXmega128A1U in our product. Sadly this chip even though powerful, is super sensitive to voltage glitches and flash erasure. Mine has a bootloader so I can do software updates, Even with tons of filtering, and the BOD enabled continuously with the thresholds set it, every great once in awhile i find a device that is stuck in a bootloader reset cycle and flash memory erased. Its weird. Only reason why the bootloader remains is I have the fuses set to make it read/write locked.
  3. techknight

    SE/30 PDS Adapter Epic Blunder

    Thats.... Stupid. usually its the other way around. your package is larger/heavier than the label. Thats odd...
  4. techknight

    Mac SE Monitor On/Off Switch

    you just need to tack a couple capacitors. 0.1uf ceramic/film, and 1uf electrolytic. across the VCC/GND lines directly at the chip. Also, a 5.6V Zener diode with the stripe side of the diode body soldered on the VCC pin, and other lead to ground. Then, put a 10 ohm resistor between the wire coming in from the switch, and the chip's VCC where all the above parts are attached. this will serve as a dump resistor if something were to overvolt or short causing the zener diode to clamp. You could go with the metal film non flammable type here. Maybe fusible type so it pops open if failure.
  5. techknight

    Mac SE Monitor On/Off Switch

    Wouldnt it have just been easier/safer to put a switch in the sweep supply at pin10 on P3? You will blow out that 74LS IC eventually doing it the way you are doing it. At minimum you need a Zener diode, a resistor, and capacitor filter network now at the IC. Just C23 alone isnt good enough anymore now that you have wires running half way to China and back, along with EMI generated by the switch, which is now closely coupled with the 12V line. All kinds of bad here. But hey, at least you tried.
  6. techknight

    Should it be recapped?

    looks like its nearly burned, so yea i would say that IC is shot. But that is the least of your concern. The bigger concern is the chain-reaction collateral damage potential that happened when the IC blew out. How many other parts went with it?
  7. techknight

    SE/30 PDS Adapter Epic Blunder

    Not sure of the feasibility, but it may be worth taking a few of those more badly damaged ones, and sending them to a Chinese reverse engineering house to see if the chips can be reverse engineered and the logic put into an FPGA or something.
  8. techknight

    512K Flup Flup Flup and Schottky diodes

    You cant reliably read Diodes in resistance mode. you need to use Diode check mode and check the voltage drop across them. Best test is out of circuit. (by removing them).
  9. techknight

    SE/30 does not boot

    Well, if it has one of those Quantum hard drives, its of no surprise this is happening.
  10. techknight

    LC575 screen

    Unless the thing has 50,000 hours on it and the CRT has gotten weak. its rare, but I have seen a couple computer monitors this has happened to. IBM PS/2 monitors being one of them, I have an IBM PS/2 monitor that the CRT has been worn into the ground. Has burn-in of course, but the emissions from the electron gun are so weak, turning up the brightness has severe color bleeding and blooming. Thats how you know the CRT is done for. Surprisingly, I found a NOS replacement. Havent changed it out yet though.
  11. techknight

    Apple 13" Monitor failing

    Ohh ok, thanks for clearing that up. These particular monitors are KNOWN for capacitor issues, so that is likely the cause. Sometimes the flyback housing can crack and start developing arcing points, but youll smell the corona it gives off if this is happening. More than likely though, you have bad caps, especially the two or three near the horizontal drive stage.
  12. techknight

    Mac plus probing signal at J8 pin 1

    It could be. You would have to try a known good PAL from another logic board if you had one. otherwise, you would have to burn a new PAL which I dont think the bitstream files are out there for the Plus.
  13. techknight

    LC575 screen

    The trinitron CRTs are pretty much all the same. that CRT, (if its the same size) can fit in some of the other Apple Trinitron monitors of the same size. I know some of those displays were actually 13" but the CRT may still be the same.
  14. techknight

    Mac plus probing signal at J8 pin 1

    Your video signal is kinda weak. Might need to look into that. Check the CRT Neck board for a shorted video driver transistor, and/or check the logic IC on the analog board where the video is gated through. Also probe the video signal on the logic board as well. it seems as if the signal for the video is being damped for some reason.
  15. techknight

    Apple 13" Monitor failing

    I would almost need to see a picture of what your describing. CRT Monitors are very complex little devices and it can be many different things to cause those symptoms. Could be capacitors, could be the video amplifier IC, could even be the flyback itself.
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