Recent content by thetech

  1. T

    820-00281 A1707 No sound from speakers after liquid spill repair.

    Customer didn't want to wait any more, took it as is. Guess we'll never know what the problem was.
  2. T

    820-00281 A1707 No sound from speakers after liquid spill repair.

    Don't have speakers for this. I did test them and all 4 are 4 ohms. Also tried just the right speaker and just the left. I feel like I'm missing something stupidly obvious.
  3. T

    820-00281 A1707 No sound from speakers after liquid spill repair.

    Power rails seem fine, PP1V8_S0 is 1.8v and PPBUS is 12.59 at all 4 amp chips. AUD_SPKRAMP_RESET_L is 1.8v. One thing I noticed is. VREF_AMP_WL is 2v while booting and drops to 0 when booted up. Can't find datasheet on MAX98706, any idea what VREF_AMP_WL, VREF_AMP_TL etc do? I'm really lost...
  4. T

    820-00281 A1707 No sound from speakers after liquid spill repair.

    820-00281 board was liquid damaged. Corrosion around U7650 and U6400. Would not power on. Replaced a few damaged components around U7650 fixed the power problem. Now no audio through speakers. Audio through headphone jack works. U6400 had corrosion underneath it. Replaced U6400, problem...
  5. T

    820-3476 Intermittent backlight

    Yes original charger. Tested with new LCD, same problem. Haven't checked backlight circuit voltages, don't want to put time into a potentially unrepairable problem and customer is considering purchasing a new one anyway.
  6. T

    820-3476 Intermittent backlight

    Late 2013 13" 3476 board, backlight goes dim (can see video on LCD with flashlight) after 1-4 hours. Sometimes works fine for days on end. No sign of liquid damage. Thoughts? I really don't want this thing on the bench for days on end.
  7. T

    820-2849 Bad GPU?

    820-2849 no sign of liquid damage. Powers cycles on and off for about a 1/2 second, during that time fan spins and all rails appear to be present. Not much experience working on this board, I'm starting to think GPU is toast. Any thoughts? Thanks
  8. T

    [SOLVED]820-4924 Black screen w/lines after waking from sleep

    Thanks Duke. Figured it out. Same thing with another LCD. U8300 was pulled from a scrap board, replacing it again solved the problem.
  9. T

    [SOLVED]820-4924 Black screen w/lines after waking from sleep

    820-4924 Liquid damaged. Replaced a few corroded caps and resistors, replaced burned LCD connector and LCD cable. Had no video internal or external, replaced U8300. Everything working fine now except screen is black with backlight on and about 1" of faint vertical lines when waking from sleep...
  10. T

    820-00239 A1706 Screen lights up, no image on LCD.

    Thanks Duke. Noping out of this one. Don't have an LCD to try, not going to buy one just to test.
  11. T

    820-00239 A1706 Screen lights up, no image on LCD.

    Backlight works, get video to an external monitor, LCD just lights up black. No sign of liquid damage anywhere. Not had one of these with this problem before. Poked around schematic a bit, not sure where to start.
  12. T

    820-3481 A1419 iMac No Backlight

    Late 2013 27" iMac. No backlight, definitely has image on LCD. Checked pins 1-4, 2-5 and 3-6 on BKL connector, no voltage at all. Can't find a schematic for this board anywhere. Replaced LCD cable and reset PRAM, no change. Grateful for any help on this.
  13. T

    Slightly OT, 820-3228 2012 Mac Mini Server has power no chime

    Couldn't find any burned or missing/broken components. Probably shorted something somewhere. I knew this one was a long shot, don't know why I even took the job. Thanks for confirming no info available.
  14. T

    Slightly OT, 820-3228 2012 Mac Mini Server has power no chime

    Customer installed second drive in this 2012 Mac Mini Server. Said a metal clip near power supply came loose and touched the board. Now it powers on, no chime no video. Wondering if anyone has any ideas as I cannot locate a schematic anywhere.
Top