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New details. The board is getting warm, but no booting. The board is in S0 state. Have so far many rails: SMPS = 19V, 0.198 AMP 1. PPBUG3H = 8.20v 2. PPVRTC = 3.3V 3. PP5V_SO = 5V 4. SYSCLK_CLK32K_RTC = 32.768 MHZ 5. SYSCLK_CLK25M_SB = 25 MHZ 6. CPUIMVP_VR_ON = 3.3V 9. ALL_SYS_PWRGD = 3.3V 10...

New details. The board is getting warm, but no booting. The board is in S0 state. Have so far many rails: SMPS = 19V, 0.198 AMP 1. PPBUG3H = 8.20v 2. PPVRTC = 3.3V 3. PP5V_SO = 5V 4. SYSCLK_CLK32K_RTC = 32.768 MHZ 5. SYSCLK_CLK25M_SB = 25 MHZ 6. CPUIMVP_VR_ON = 3.3V 9. ALL_SYS_PWRGD = 3.3V 10...

1. i detached U6990, i have not short/continuity to ground. 2. I placed another U6990 from donor board. 3. I changed the resistor 10ohm resistor before diode D7005. And the 10ohm resistor(R7005) broke right away. What could be the cause for that?

Thanks, 2Informaticos.. very valuable information to know. I did have some issues problem when I come to think about it which you mention it herw about the SMC. Im checkign this board now and will revert back here, so far I have no display or image.. black screen..

HEY EVERYONE. I DECIDED TO CONTINUE THIS THREAD AND DECIDED TO FIX THE LAPTOP ANYWAY. (NEVER GIVE UP) I decide to not give up on the motherboard. Giving up its not the way to success and not the way to learn things. So I spent nearly 3 hours extra fixing the left Fan. I used the hot air gun to...

Case open again!!!

1. I have now PP3v42 stable after changing the SMC which I had put in the wrong direction. I placed a brand new SMC. 2. The computer draws 19v and power cycling between 1.200/300amp. The fan is spinning ok. 3. But no image - still missing So i will keep hunting the issue and revert back to you...

Update: This is going to sound funny. Never happened to me before. But I happen to put the SMCin the wrong direction. GO FIGURe why the short :) But I came to solve that by John giving me the advice on checking for shorts on all PP3v42. So thanks John to you. I'm going to solder on a new SMC...

Thanks, John, but there's is no U1900 on this board..? 820-3332.. perhaps u mean another IC?

1. I have changed all 3 caps(C6999, C6991/3).. C6999 = zero volt on both pins. C6999 in continuity mode beeps on both sides to ground. How is that possible when the cap is not broken/nor shorted? 2. I reballed the SMC earlier because that one was creating issues with P5VS4_EN to U7201. 3...

Hi, 820-3332 Macbook retina 15" been working on the board for some time now, and it seems new problems keep coming up. currently R6920 which is a 47 ohm resistor for (PPDCIN_G3H_ISOL) ITS BURNING HOT. its boiling.. and ive changed it twice.. I do get the greenlight on charger with 0.260mA...

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1. The audio was crackling and making bizarre sounds. Now after taking out the motherboard there is NO audio/sound at all coming out of the speakers. 2. The sound icon is blurred out. No water damage. Anyone had the same problem? UPDATE: 1. I found corrosion on Audio codec IC U6200, 5v on...

That's a strange thing.. There must be an internal short on the board.. I have removed all the caps. all of them 6x 4.7uF. One of the shorts the one I posted C6991, that pad is shorted to ground.which is the line for PPVIN_G3H_P3v42G3H. So how do I go about to fix that if it's an internal short...

There is a short on this capacitor pad C6991. Even though i took away the capacitor. its still shorted to ground. How is that possible? must be a short under/inside the board itself. The cap was burnt before I took it off. That cap is attached to U6990. Could it be U6990 isbeing pulled down and...

R6905 both pin showing "OL" open line in diode mode. I injected voltage and tried to hunt for short. No short from what I could see. The 10 ohm resistor is new.. Its very weird..

sorry, ive been off the forum a while so forgot to post the board nr. 820-3208 Macbook Air R6905 is original and has the same value (10).. Ive changed the diode as well. In case its pulling it down. Still doesnt work. very strange! Could it be somehthigng inside ethe board thats messing it up...

Green light is missing. R6905 pin 1 = 19v, Pin 2: 0.027mv What is pulling it down? I have changed the D6905 and same problem. could it be the chip U6990 that is pulling it down? ive changed that one as well. I removed all the caps connected to ground under U6990. any ideas pls why R6905...

Problem is solved gents.. Someone mentioned issued with pm_slp_s4. so I started there and traced back. Was missing pm_slp_s5 rail as well. So i continue tracing back It was U8020 (TPS22924) Missing 3v output voltage. It had pp3v3_s5 input and pp3v3_sus_en input. 2informaticos and JohnB8812...

Tmr I will buy some new ultrasonic cleaning. To be fair. I had some ultrasonic cleaning inside that might have been old, and i happen to mix it with Isopropanol.. haha.. I know.. Its pretty dumb thing to do.. 1. So i guess thats part of it. However I will take John advice and try ultrasonic it...