Recent content by Kittu

  1. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    Hi! Having changed U8900 and it?s related RC components, replaces Q8930 I have PPVCore as 1.05 which drops to 0.89 on fan spin (GPU has been removed to troubleshoot for now). HOWEVER , GPU FB Supply and GPU 1V05 Supply remain 0V on fanspin with GPU removed. My question is, are the supply...
  2. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    GPU and Q8930 replaced. Coil resistance drops to 5.6 Ohms. System boots. No excessive heating of any component but still no vcore GPU and hence no eDP image. please advise on further diagnosis.
  3. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    Will replace GPU and update asap.
  4. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    R/C Components check OK around the 62882 and Q8930. Request you to point me to the specific test points. Further, PPVCore_GPU is 0.97V when Q8930 heats up. Is there a possibility of the GPU (despite showing 16-18 ohms at coil) being somehow internally shorting leading to a virtual overdrive...
  5. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    As stated, fans spinned, system chimed with Q8930 removed. However, Replacing Q8930 as well as 62882 and powering the board with MagSafe results in F7040/41 voltage dropping to 3.2V (resultantly no fan spin/ chime anymore) with coil showing a PPVCORE_GPU voltage of 0.97 and Q8930 heating...
  6. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    Is there a way to check if the Q8931/61 are good by on-board diode mode voltage or normal resistance checks? kindly advise on this as finding replacement equivalents introduces another variable in the equation of an already complicated scenario of GPU/Q8930/62882
  7. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    Please advise if I also need to replace Q8961/31 649135PBF along with the Q8930. If so, as the 649135PBF is getting hard to find, a reference source will be highly appreciated.
  8. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    L8930 to ground does show 18 ohms!
  9. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    Alas it was powered up before I posted when the Q8930 was shorted.... 18Ohm was Fuse F7040/41 to ground PRIOR to removal of the Q8930. Have ordered the Q8930 at Mauser so will take a few days. At the moment after removing Q8930 and replacing the 62882 I did power up with GPU and CPU both...
  10. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    Removed Q8930. Fan spin and system chimes - though the original issue of eDP remains to give a background, I had to remove the U8900 as pin 39 was perhaps shorted to pin 40 though the embedded LCD worked. After replacing U8900 the display disappeared. I again removed it. then suddenly the issue...
  11. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    Aaaah! My Bad. Though I just checked, removing Fuse 7040 and 7041 shows 12.5V on pins 1 of the fuses. meaning something after the fuses is pulling PPBUS_G3H town to 2.5V. Hope this didn't fry the Q8930!
  12. Kittu

    Macbook Pro Retina A1398 PPVCORE_GPU

    Hi: Im having an issue with a A820-3332 motherboard with PPBUS_G3H at 2.8V instead of 12.6V No chime, no fan spin one wire-circuit working with green light on MagSafe. On scouting, I find this may be perhaps because of PPV removing U8900 (62882), the PPVCORE_GPU shows 18 ohms to ground! Please...
  13. Kittu

    820-3023A Missing PP3V3_SW_LCD_UF

    Hi! Yes, the supply does come after 5 seconds for a couple and then disappears. On investigating further I found the case of a bad pad under L9004 leading to the system not registering the EDP. Replacing the Inductor and making good the connection restored the EDP display as well as backlight...
  14. Kittu

    820-3023A Missing PP3V3_SW_LCD_UF

    Tried with known good panel and rechecked the connection pins. No 3V3_SW_LCD still...
Top