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About techknight

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  1. Nice! that looks like uninitialized RAM, so the CPU isnt starting up for some reason. Wonder if theres another address/data line that was missed or unconnected.
  2. Solder paste and heatgun method only works if you have a stencil for the PCB and you can apply the proper even amount of paste. just going willy nilly with the paste without a stencil is asking for a disaster. Something to keep in mind.
  3. Yeap this is the area to investigate. Also, you can use the blowdryer/heatgun method if the freeze spray makes it worse. heat would make it better albeit temporarily. Regardless, now its time to try and narrow the field, hitting it component-by-component and watching for changes in between.
  4. These are one of those sheet-by-sheet style schematic. Regardless, you have to follow the connection points back to another sheet which has the pinouts of the connectors. I don't want to sound cold, but I cant really teach you how to read a schematic, as its a super involved process and I am not really a good teacher. If you don't know how to read schematics, you have a long long way to go. May I suggest youtube videos or something for basic electronics training and schematic reading. I know there are some good ones out there.
  5. Looking at your picture closely, you do have a handful of issues with the soldering of that CPU. you should use a flux pen, and then drag soldering with desoldering braid for cleanup. the ATMega128A1U is the same package, and I deal with those almost daily and have 0 issues with this method.
  6. I was gonna say this board needs thoroughly cleaned alongside all the caps being replaced. Then if that fails, replace opto-isolator, shunt regulator, and the SMPS controller if necessary.
  7. Not everyone has access to that though, I dont. So the tube idea is a decent solution.
  8. This is known as vertical fold-over and 9 times out of 10 its most certainly caused by a bad capacitor in the vertical output stage. If you recapped this already, you need to go back and double-check your work. a cap was either missed, wrong value installed, a solder bridge, backwards, etc.... The vertical output IC could be damaged as well, but its rare.
  9. Could be anything to be honest. youll have to troubleshoot it. Meanwhile, why in the heck would colby make such an abomination? the original Mac would have been smaller
  10. Then you need to follow the schematic in the keyboard section and verify all the traces from the two sockets back to the keyboard controller IC. If that verifies good, then replace keyboard IC.
  11. broken traces between the keyboard connector and the keyboard controller chip. Try plugging in the keyboard on the right side instead of the left side to see if the problem goes away. the caps eat the traces right there on the left hand side where the power controller circuits are, and so are the keyboard traces.
  12. Oh, Nice discovery! Now just need to figure out what size the bumpers are on the drives which have the rubber bumper actually under the platter.... Only can service single-platter drives this way, But.... still doable.
  13. I read through that, appears its a disk you have to boot from an SE that performs the tests on the Portable. Wonder if anyone has gotten a copy of said disk and archived it.
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