Recent content by joshAU

  1. J

    820-00850-A no display on internal or external screen

    Ah, OK. I had assumed that the trackpad click was a sign of life on all of them. Plus the fact the power button would seem to turn the trackpad on and off. However, no signs of life from any USBC port with a USB with a LED on it. PPVCC_S0_CPU = 0v PPBUS_HS_CPU = 12.56v PPVPCORE_S5 = 0v...
  2. J

    820-00850-A no display on internal or external screen

    Hi again. I get 20 volts to F3001 when connected to the outer USBC port on J3300. The trackpad clicks, so the unit is turning on, but there is no display. The power button will turn the unit on and off - i.e. the clicking will stop, or start, again. There is no signs of any liquid ingress to...
  3. J

    820-00239 missing PPBUS_G3H

    Fair enough. Yep, dead. Thanks once again for your help and advice.
  4. J

    820-00239 missing PPBUS_G3H

    I'm still learning! I removed F8400 to see which side had a short. I only injected 1v, which I thought would be safe. :( The max amps it drew was 2.5A. So do you recommend replacing U7960 and hoping?
  5. J

    820-00239 missing PPBUS_G3H

    Hi all. I have a dead 820-00269 from an A1706. Missing PPBUS_G3H. I get 20v on F3001, however no voltage on F8400. I removed F8400, and injected 1 volts into pin 1 and found U7960 getting very hot. I removed that and there still appears to a direct short (zero ohms) to ground on the pads of...
  6. J

    820-00239 dead. Missing 20v.

    Thanks again for your advice 2informaticos. Unfortunately, that job went pear shaped. :( What temperature do you need to remove UB400? I ended up overheating the board, to the point that other components started floating....its game over unfortunately for this board. I read that all 4 CD3215...
  7. J

    820-00239 dead. Missing 20v.

    Hi again 2informaticos. Thanks for your advice once again, and sorry for the delay. OK, I measured all 4 LDO rails on all four CD3215 chips. In diode mode with red to ground, most rails measure between 524 & 570. However, 2 rails do not, and appear as short circuit. These are: UB400...
  8. J

    820-00239 dead. Missing 20v.

    Hello again. I have a 820-00239 that appears dead - no life, no fans. No USB activity at all. No signs of any liquid anywhere on either size of the board. Tried with known good AC adaptor with just the bare board. I don't seem to get 20v anywhere - the most I get is 5.7 volts. I'm also...
  9. J

    820-3437 short on PPVRTC_G3H even with U1900, C1910,C0890,C0891 & C0292 removed - Dead CPU?

    Hi again all. Short circuit to ground on PPVRTC_G3H. I suspect the CPU is dead, but thought I'd check before writing it off. 820-3437 Magsafe light OK, no fan, no chime or anything else. No signs of liquid ingress or other damage. I've removed all caps on PPVRTC_G3H, short to ground (0.08Ω)...
  10. J

    820-00928-A not detecting integrated SSD after liquid ingress.

    Thanks again 2informaticos. Sorry for the delay. I had covid and was away from work.
  11. J

    820-00928-A not detecting integrated SSD after liquid ingress.

    Hi again. I have an 820-00928-A that does not detect the internal SSD. This unit was apparently water damaged. Another technician cleaned the board, unfortunately, so I cannot see where the liquid got onto the board. There are no signs of corrosion anywhere. Booting from a Monterey boot disk...
  12. J

    820-00165-A Not display on int or ext screen. Orange light and fan spins,

    OK. Cleaned J6100 - was a tiny residue of crap still there surprisingly, but no change. Cleaned both U6100 and U6101 - no change. Checked voltages on SPI Bus Series Termination resistors. SPI_SMC_MISO 3.31v (measured at pin 2 of R6114) SPI_SMC_MOSI 0v (measured at pin 2 of R6115) SPI_SMC_CLK...
  13. J

    820-00165-A Not display on int or ext screen. Orange light and fan spins,

    Thanks 2informaticos. Sorry, i had tested video prior to checking if there was USB activity. I guess its easier to go the other way. Still learning. :) I was also rushed yesterday, so apologies for the typos... PPBUS_G3H is 8.56v. PLT_RESET_L = 3.31v
  14. J

    820-00165-A Not display on int or ext screen. Orange light and fan spins,

    Hi all. I have a water damaged 820-00165-A that has no display, either on the internal panel, or on an external screen. There is zero change on the screen when power is connected. I cannot see an Apple logo or folder question mark while shining a light from the back. I have tried another...
Top