• Hello MLAers! We've re-enabled auto-approval for accounts. If you are still waiting on account approval, please check this thread for more information.

Recent content by GiGaBiTe

  1. G

    Sourcing Legit MC68882 FPUs - Data

    Must be one of the classier remarked parts, since it passed the CRC Lectra Clean solvent test and it looks to be laser etched. I replaced the CPU as well because the original 25 MHz 68030FE25B ran burning hot and was unstable. Even at its stock speed it ran burning hot for the 30 years that...
  2. G

    Sourcing Legit MC68882 FPUs - Data

    I wonder if the one I have is legit. The board boots with it installed (LC III upgraded to LC III+ specs), but I've not done extensive testing with it yet.
  3. G

    Mac PLus Q1/Q2 transistor replacements?

    The "two prong" transistors you're looking at are probably TO-3 style transistors. Yes, the case is one of the connections, usually the collector. This transistor has similar characteristics to the one you need, but you'll need to get its sibling if you want to have a matched set (MPS650 - NPN...
  4. G

    Overclock Mac LC II?

    Nice, so you can have the best of both. If he ever gets around to adding cache to the upgrade, it'd make it a whole lot snappier on the crippled 16 bit bus.
  5. G

    Overclock Mac LC II?

    There is no easy way to overclock an LC II and not have other things affected on the logic board. The easiest solution would be a logic board swap, or installing a PDS card processor upgrade. The downside with this is that if you have a network card, you have to choose one or the other. Someone...
  6. G

    Variations in benchmark performance on LC475/Quadra 605 with 68040 CPUs and VRAM

    I'm a few years late to the party, but I came across this thread when browsing information on the J18 jumper. I've hotrodded one of my Quadra 605s to 40 MHz with a full 68040. Removing J18 made a measurable, but insignificant performance difference, depending on the test. Results were 2-5%...
  7. G

    Quadra 605 - J13 fan connector

    As long as you get the power and ground pins in the right places, modern fans will work fine. You'll want to make sure you don't try and backfeed the sense wire with +12v (usually yellow or white) or the PWM wire (usually blue) or you'll likely fry the fan.
  8. G

    Classic Power Supply with weird voltage, repair

    Have you checked any of the resistors? I've had bad resistors cause SMPS power supplies act erratically. They can go open, short or drift far off their rated value. They can also start arcing internally and cause intermittent connections. There are color code calculators online to get the...
  9. G

    Macintosh SE wobbly raster (analog board problems)

    Well the bad part just revealed itself, the horizontal output transistor just went thermonuclear. Whole house stinks like burning silicon, lovely. Customer will definitely need a replacement analog board now unfortunately.
  10. G

    Macintosh SE wobbly raster (analog board problems)

    @bibilit My method was to tap the analog board with the handle of an insulated screwdriver. I'm pretty sure all of the bad joints have been fixed because nothing happens when tapping anymore. Initially the tapping would cause bright white raster lines and eventually the machine would crash with...
  11. G

    Macintosh SE wobbly raster (analog board problems)

    Not sure what I did, but it got better after reinstalling the old 3.9uF deflection cap, and another cap on the horizontal section of the analog board. I also cleaned the potentiometers and reflowed some still suspect looking solder joints again. https://i.imgur.com/0YCy9Al.jpg It's now back to...
  12. G

    Macintosh SE wobbly raster (analog board problems)

    I'm working on resurrecting a Macintosh SE for a customer. Everything has been roses and sunshine except the analog board, which just doesn't want to work. After getting the machine to actually boot (stuck floppy, stiction miniscribe drive, bad RAM, leaking PSU caps, bad caps on motherboard...
Back
Top