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OleLila

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  1. OleLila

    G4 MDD PSU

    Thanks for the link it was very helpful, sorry to repeat up information that is already out there. ....I have the same video card that you have and it inspired me to reassess and I found that I can shut the case with the 500 watt power supply mounted in that area. So the power supply swap worked.....on with the original power button, resets with a power button hold down, used an external power adapter for the display. The ATX to MDD adapter board was handy primarily because it has a standby/on button that allows you to turn on the power supply and test all of the voltages on the MDD molex before plugging into the logic board. However it is bulky and to close the case with it in place I will have to leave out the hard rives opposite of it to make room. If the power supply If the power supply you have has colored wires, I'd opt for the molex removal tool instead. Some of the descriptions sound like a wire to wire swap (just changing the location of the pin connectors) but I did have to double up on a 5 volt and 12 volt connection. I put a jumper wire from ATX pin 8 (power OK) to ATX pin 2 (3.3 volt ) then attached that to pin 18 of the MDD, this is described in the link above. I cut off the "plus 4" portion of the 24 pin atx connector and plugged in one of the CPU 4 prong connectors from the ATX power supply in its place to get 2 additional 12 volt connections. The MDD needs 4 pins on 12 volts so I attached 2 of the 12 volt lines to one of the 12 volt lines now available from the ATX cpu power (one of the 12 volts now in the "plus 4" portion of the cable).
  2. OleLila

    G4 MDD PSU

    My video card is full length, it’s looking like the largest power supply I’m going to be able to put in and get the case closed (and keep cost under 40 bucks) is 350 watts. Searches say this if ok if you are not using adc to power a monitor. Still have to build the cable and test it on a 500 watt power supply before springing for a 350 watt to fit in case.
  3. OleLila

    G4 MDD PSU

    Going to try this https://www.amazon.com/gp/product/B01NBU2C64/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1 and this http://atxg4.com/mdd.html To any electricians out there, if I used a separate DC power supply of 25 volts to pin 14 in parallel with the atx power supply could I still use the adc power for adc monitors?. If the dc supply pugged into the same outlet as the ATX are they grounded the same?
  4. OleLila

    G4 MDD PSU

    Any news or follow up on the silver door G4 power supply repair or replacement successes?
  5. OleLila

    twenty one pilots - level of concern - new lyric video

    Thats fun, awesome detail and work there
  6. OleLila

    A Bit Of A Rarity

    I had never known of the Twiggy Mac before this thread. Looking forward to the rest. Thanks.
  7. OleLila

    A Bit Of A Rarity

    This looks like one of those deals where OldMacGuy disappears and this thread disappears and its all best if no one asks any more questions.
  8. OleLila

    Help with my Macintosh Classic

    May or may not be helpful to your exact problem but pretty good series right now on troubleshooting several Mac classics....go to YouTube and search Adrian’s Digital Basement
  9. OleLila

    Laser 128ex....how to revive

    This is after I removed capacitor and cleaned up with wick. isolation is over and had to clean up for a while....will take the laser apart again hopefully in a couple of weeks and look at u26 as suggested and post follow up
  10. OleLila

    Laser 128ex....how to revive

    ......and right on cue that's what I get for giving a definitive answer, I am measuring these but blew this one (maybe got it mixed up with the C127 change).....anyway, was going to take one more look at C286 this afternoon and just replace it and turn on, but when I took it off...yes there is a short across even when cap286 is removed ...anyway flipped the board over and thought I was going to be removing a solder bridge but it looks like its by design (see picture)
  11. OleLila

    Laser 128ex....how to revive

    Replaced C286 (not 266...schematic ink close together) 68pf......not sure if it is just the size of the cap or if I charge the cap by measuring, but it still looks like a short across the new cap. Replaced Cap 127 between pin 14 of U26and gnd because it looked burnt after I replaced U26 Replaced crystal XTAL1. Still Nothing happening....same measurements with oscilloscope
  12. OleLila

    Laser 128ex....how to revive

    Pin 7 is ground and pin 14 is at 5.02 volts. Will go to find a 68 pF cap to replace C266...with U13 and D14M checking out, is this cap bringing down everything still a possibility? What about the reset circuit?
  13. OleLila

    Laser 128ex....how to revive

    I did measure pin 8 above, not pin 18. These pictures are of pin 18 of U13....14.35 frequency is there.
  14. OleLila

    Laser 128ex....how to revive

    When I turn the machine on and measure first with voltmeter then with oscilloscope..........pin 1 of U13 shows no voltage and no frequency detected, at the same time PIN 2 of U13 shows 1.34 volts and frequency 14.35; PIN 8 of U13 shows 4.76 volts and no frequency detected, Pin 9 of U26 shows 14.35 frequency, PIN 8 of U26 shows nothing. One time briefly (maybe over the course of 2 minutes) when I measured PIN 8 of U13, I got a 14.35 frequency however I quickly plugged in the screen (nothing on screen) and when I got back to measure other pins, it had reverted to the 3.74 volts again and all as above. To be transparent, when I measure these pins, there is no doubt that as I put the probe on a particular pin and look to the oscilloscope, I have moved the probe and shorted between the pins. If this is ruinous then its all out the window....not much room for error at all and hard to imagine getting through all of these measurements, esp on the smaller chips, and not eventually getting between 2 pins. I ordered replacement part for U13 (74HCT244) but received 74HCT244N which I did plug in and try but showed no change in activity. So when I get a chance my plan is to go ahead a replace shorted C286 (68 pF) and crystal XTAL1. Have to balance this with the day job and activity but hope to get to this in the next couple of days. Very much appreciate your looking bibilit.
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