• Updated 2023-07-12: Hello, Guest! Welcome back, and be sure to check out this follow-up post about our outage a week or so ago.

Recent content by techknight

  1. techknight

    What size and angle for a PowerBook 145B screen polarizer?

    That has to reeeeeeeeeally smell bad. I peeled a polarizing film off of a 2300c display and man... putrid.
  2. techknight

    What size and angle for a PowerBook 145B screen polarizer?

    I wonder if there is a chemical process to dissolve the remnant adhesive on the glass. because the razor method seems like a pain in the ass and can go incredibly wrong if you slip and hit a ribbon.
  3. techknight

    So, I bought a portable…

    its because the DC input goes through a resistor... need full battery voltage to switch on the FET
  4. techknight

    Macintosh Color Display: How did I royally screw this up???

    I would also fathom that is part of the reason the LCs and other machines are shielded, is to help with EMI produced by the HDD, FDD and PSU which could radiate into the monitor and introduce wobbling. Also two CRTS side-by-side will do the exact same thing.
  5. techknight

    Macintosh Color Display: How did I royally screw this up???

    Make sure the monitor isnt near any alternating magnetic fields/EMI sources, ive occasionally found fans, transformers, and other nearby objects to cause CRTs to wobble.
  6. techknight

    30MB Miniscribe Hard Drive from Mac SE -- reads data, but cannot be written to!

    Is this a miniscribe drive? I have seen the write amps fail on these drives in the past. Entirely possible thats what happened. The head isnt getting the write current from the write amplifier IC.
  7. techknight

    The Color Classic LCD Project.

    I have never studied the CC/LC5XX signaling in that amount of depth before, I doubt that anyone has.
  8. techknight

    Macintosh Classic Sad Mac RAM expansion error

    Necropost.... I just ran into a Classic doing the exact same thing. I am suspecting the 74LS174, I will know further when i get back to it.
  9. techknight

    Twentieth Anniversary Mac PSU replacement

    Did you actually test the 1 ohm resistor associated with it to see if it was open? because thats how you determine if the TOP Failed or not...
  10. techknight

    PowerBook 5300ce Plastics Replacement in 2023?

    Seems like @ThisDoesNotCompute is very good at modeling parts to fix these things.
  11. techknight

    PowerBook 170 with e-ink screen

    The UV produced from the bulb itself will accelerate this. It might be possible to retrobrite, or vaporbrite, but it would probably re-yellow with time.
  12. techknight

    PowerBook 170 with e-ink screen

    Its the plastic light spreader/diffusor plastic which yellows as it degrades.
  13. techknight

    blown component on Sony MP-F75W

    Ive never personally ran into it before, at least not yet but just looking at the pictures I can map the circuit out in my head pretty much right away and see whats going on, luckily.
  14. techknight

    blown component on Sony MP-F75W

    yeah Q4 is the high-side VCC switch for IC3. Whatever happened with IC3 blows Q4. Q4 and Q9 are NOT zener diodes! They are transistors. Q9 shorts CN3 1 and 3 together when enabled. R48 is a pullup to keep the transistor turned OFF when not asserted by the control circuitry.
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