820-00165 No 5v or 3v3.

RESQ-MYTECH

New member
Hi all. Not posted for a while as I seem to be getting on OK with the logic board repairs. However, I think I am not seeing the wood for the tree's. I am searching around and losing track of what, where, why and when.
MBA A1466 820-00165
Magsafe- Green to Orange- no power on- no fan spin
PPBUS_G3H = 8.597v
PP3V42_G3H = 3.428v
PP5V_S5 = 0V
PP5V_S4RS3 = 0V
PP5V_S0 = 0V
PP3V3_S5 = 0.307V
PP3V3_S4 = 0V

Basically, all the 3v3 rails are 0v

I have seen this issue addressed a few times on the forum and by our "leader" but for the life of me I can't seem to locate any of the videos or posts. I am probably not putting in the right search terms but being thick.. who knows.

My deduction, I believe there is an IC that produces both the 5v and the 3.3v.

Searched over the board and so far, there was corrosion around pins 18 to 21 on U7501 so I removed and replaced it with another.
Corrosion around pin 1 of R4411 and all 6 pins on Q4410. Q4410 was replaced. Pad on pin 1 of R4411 was gone so jumped to pin 1 on R4410.
checked rest of the board.... no corrosion. I don't think the board has been looked at before as even though it is cleaner that I would have thought as there was a little corrosion, there are loads of fibres on the board giving me reason to believe it has not been ultrasonic cleaned.

Prior to disassembly, I did do a SMC reset and a PRAM reset. I have also tested SMC_RESET_L which gives 3.384v and SMC_MANUAL_RST_L gives 2.754v

When the magsafe i connected the CPU does get warm. And even though I do not believe for one second it is a contributing factor, I have "carefully" removed J6100. I don't know why but Louis seems to have good results removing this.

Is there anything else I should be checking, please?
Thank you in advance.
 

RESQ-MYTECH

New member
Hiya, as an update, if it helps, I have followed page 62 of the schematic down and below are all the voltages of the first line of all the power rails.

PPBUS_G3H= 8.641v
PPBUS_S5_HS_COMPUTING_ISNS= 8.639v
PPBUS_S5_HS_OTHER_ISNS= 8.639v
PPDCIN_G3H_ISOL= 16.909v
PPDCIN_G3H= 16.913v
PP3V42_G3H= 3.437v
PPVRTC_G3H= 3.356v
PP5V_S5= 5.036v
PP5V_S4RS3= 0v
PP5V_S0= 0v
PP3V3_S5= 3.357v
PP3V3_S4= 0v
PP3V3_SUS= 3.355v
PP3V3_S3= 0v
PP3V3_S0= 0v
PP3V3_S4SW_SNS= 0v
PP3V3_S0SW_SSD= 0v
PP3V3_S4_TBTAPWR= 0.003v
PP1V8_S3= 0v
PP1V2_S3= 0v
PP1V05_SUS= 1.066v
PP1V5_S0= 0v
PP0V6_S0_DDRVTT= 0v
PP1V05_S0= 0v
PP1V05_S0SW_PCH_HSIO= 0v
PPHV_S0SW_LCDBKLT= 0v
PP15V_TBT= 0v
PP3V3_TBTLC= 0v
PP1V05_TBTCIO= 0v

Unfortunately, I do not have another 820-00165 here to make a comparison with.
Just in case I was being trolled, I have also changed the DC-in board and the charge ribbon.

Please help oh guru's of the mac world.
 

2informaticos

Administrator
Staff member
No reason to check S0 voltages, when missing S3 voltages.
Keep in mind, power sequence is S5 --> S3 --> S0.

Post SMC_ADAPTER_EN, PM_BATLOW_L, PM_RSMRST_L.
Check if PM_PWRBTNL_L reacts when trigger SMC_ONOFF_L.
If you get a pulse on PM_SLP_S4_L, all S3 voltages should pulse too.
 

RESQ-MYTECH

New member
JohnB8812
Just managed to get in touch with the customer, he "claims" he has dropped it twice from a low level onto carpet. Last time was about 18 months ago. Dont know if that has any bearing on the diagnostics.
 

2informaticos

Administrator
Staff member
Dropped machines are always nightmare to repair.

"PM_BATLOW_L= 0.036v"
PCH will not start power sequence in this way.
Are you surely using original 60/85W Magsafe 2 charger?

"PM_PWRBTNL_L..... did you mean PM_PWRBTN_L? If so I get 3.383v"
Sorry for misspelling.
I was asking for any reaction; it is steady high?
 

JohnB8812

New member
You ARE NOT Using a genuine charger BATLOW should be 3.3! Go get an OEM 85 watt MagSafe 2 from Apple or Best Buy before continuing
 

RESQ-MYTECH

New member
2informaticos I tested the voltage at probe point 639 ( just below R2223) ( as shown using Landrex ( i like Landrex)) and it showed 0.036v. I felt this was easier to locate than R1410. However, when I tested at Pin 2 of R1410 I was getting the same 0.036v but pin 1 is showing 3.334v. I removed this resistor and replaced it with another 10 kOhm resistor and now getting 3.330v on pin 2 and fan spin using both my 60w and 85w Magsafe 2 adapters.... no Magsafe 1 to 2 convertor as this sometimes gives problems. I am going to reassemble to see what happens from here and will report back

JohnB8812 All of my adapters are genuine adapters. With exception of my 60w and 85w Magsafe 1's, which came from units that I brought in, my 45/60/85w Magsafe 2 and 30w USB C all came from my local Apple store at Lakeside Thurrock in Essex, UK. I have been caught out with this before when 2informaticos was troubleshooting another A1466 820-00165 board I had in for repair.

I am putting it back together and wil let you know the result.
 

RESQ-MYTECH

New member
And there we have it... got a fan spin, a boot and folder displayed. I am going to re-attach the J6100 connector as I feel that it really was of no consequence to the issue. For the record parts swapped were U7501, Q4410, R4411. Pin 1 of R4411 was also jumped to pin 1 on R4410. Finally R1410 was replaced. I am going to soak test it for a couple of hours to make sure all is good. Thank you both for your assistance in helping me see the problems and resolving then. Kudos to you both.
 

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