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Hi i have an 820-3208 in an S0 state. but no fan spin. The missing S0 rails are PP0V75_S0_DDRVTT PPVCCSA_S0_CPU PPVCORE_S0_CPU PPVCORE_S0_AXG incidentally PP1V5_S3_CPU_VCCD is at 1.35v and not 1.5v all_sys_pwrgd is not present (50mv) I have changed Q7950 twice just in case inputs on...

Not tried that. Thanks . ​​​​are those settings stored on the SSD rather than a flash chip?

hi no efi password. the issue is that things like changing the keyboard in the OS is not pervasive. and every boot results in password reset screen (with no keys pressed). effectively meaning that a pram reset is needed each boot. is this a bios failure?

Any thoughts into why a Mac air would not be saving started to pram (eg keyboard info)? Always boots into password recovery.

I've just finished repairing an A1465 after a liquid spill, but the keyboard is resisting attempts of cleaning with alcohol. has anyone tried cleaning them in an ultrasonic bath? ditto with a trackpad - does an ultrasonic negatively effect the surface? thanks in advance. Justin

i plugged it back in over lunch to test again - flames leapt from the PCH so I think this is now officially a dead board. thanks!

NB it is the left hand of the chips that is getting super-hot (as you look at the board with the fan on the right). I think this is the PCH.

PP_3V3_S5 is present at 3.27v SMC_ADAPTER_EN is present at 3.4v PM_BATLOW_L is not present (3mV) S5_PWRGD is not present PM_DSW_PRGD is not present PCH_DSWVRMEN is not present PPBUS_G3H is 8.16v re the PCH RTC signals, which ones did you mean? PCH_SRTCRST_L is low RTC_RESET_L is low when I...

thanks for the reply, without the flex cable: PM_SLP_SUS_L 0mV PM_RSM_RST_L 0mV PM_PWR_BTN_L does not react when R5115 is shorted. stays at a stable 3.41v .

Any help with this board would be appreciated. no history to help. the board was clean; no evidence of corrosion nor any tarnished test points. all g3h rails are present and correct. Good 32.7kHz pulse coming from pin 12 of the RTC (replaced RTC in any case as I was seeing a pulsed voltage...

Good question! This is in the pile of things to do. I will try to resurrect it tomorrow and report back.

I have an old mac air board for an A1369. Fully functional I swapped out the SSD to do some data recovery on an equivalent drive and when that was complete, swapped the old drive back in. Dead. Obviously worked on anti-static basis and drive was not dropped or anything. is there any...

and removing U6620 and U6610 resolved the short. resistance to ground on PP5v_s3 is now 3.8k or so. hopefully that resolves the power issue generally. I will have time to test properly this evening (fingers crossed)

removing U6620 increased the resistance to 50Ohm. may be worth removing U6630 as well. Perhaps I blew the audio amps?

if course - as per the above, the short is on the side of pin 1. I've lifted so far the RTC, Q7940, U7200, L3405, U4800, C7291, C7290, Q4590, Q3450 and tested the resistors and other caps in the area. the low resistance remains. Lifting resistor R7267 tells me that the problem is on the pin...

Harrumph ... i have found a schematic that corresponds to the boardview now. i will trace from pin 1 of l7260 and see what i find before posting back again. thanks

I'm really getting confused by this. I suspect it is in large part because the schematic does not line up at all with the boardview files I have. I'm using drawing number 051-7546 in case that helps anyone ? on the boardview, the pin that has the low resistance is pin 1 of L7260. On the...

Hi again I'm getting only 22Ohm to ground on pin 1 of L7260. has anyone got an equivalent board they can test for me to see what's normal? injecting voltage there I get some high(ish) heat on the L3405 and C3452 pair. and some heat on the two inductors l3402 and l3403. I will remove C3452...

true. I replaced that with the TPS though !

the only major chip that was close by to where I was working was the s5 regulator (tps51125). and even that was a good 15-20mm from the area of the audio connector. the s3_en signals come directly from the MCP though. So unless someone has a better idea I fear somehow that the MCP has fried.