(347) 552-2258 [email protected]

MacBook 820-02020-A with cycling voltage , Liquid Damage

E

EcWeb.L.

New member
Hi everyone!

i'm new in the forum and fairly new to macbook repairs. I've already repaired two boards along with some iphone boards , but still learning.

As the title says i have an A2338 that has been in contact with liquid (wine). I firstly cleaned the board with ISO where the liquid was most visible then checked voltage on the usb c ports .
It was cycling starting from 5v , jumping to 20v and after 3/5 seconds going back to 5v and so on.

Having read similar cases on the forum i tried to take out F5200 then checked C5250 and i'm now getting 12.29v stable.
Out of curiosity i've also checked PP3v8AON on C5890->C5895 and i'm getting 0v there.

I'm providing images of parts of the board where liquid was mostly present.

Thanks for any suggestion.
 

Attachments

  • Condensers U5200.jpg
    Condensers U5200.jpg
    253.9 KB · Views: 4
  • UC300 Area.jpg
    UC300 Area.jpg
    264.3 KB · Views: 4
  • UC710 Area.jpg
    UC710 Area.jpg
    295.6 KB · Views: 4
2informaticos

2informaticos

Administrator
Staff member
First of all, welcome to the forum!

Be sure all resistors from affected areas are good.

Resolder F5200 and check 3V8_AON.
 
Last edited:
E

EcWeb.L.

New member
Here i am ,

With F5200 soldered back the voltage is still cycling this time it's getting to 20v for a solid 5 seconds before going back to 0v , then 5v and so on.
i'm getting 3.8v on 3v8_AON when the board is at 20v volts , so i guess that line is ok .

These are the resistors results in each area ( compared my result / schematic ) :

UC300 area
-RC333 0 / 0
-RC332 1.6 / 1.5
-RC320 25.3 k /25.5k
-RC321 20.4 k / 20.5k
-RC322 13.2 / 10 (initially oscillating from 12.9 to 8 and back)
-RC323 8.97k / 9.31k
-RC324 62.4 k / 200k
-RC325 24.6k / 27.4k
-RC326 47k / 47k
-RC327 0/0

UC710 area
-RC709 15 / 15
-RC710 0.2 / 0
-RC711 2.221k / 2.26k
-RC712 32.4k / 127k
-RC713 27.55k / 34.8k
-RC714 0/0
-RD531 75.3k /75k
-RD532 124k / 124k
-R8335(nostuff) 10.10k /100K

U5200 Area
-R5340 466k / 470k
-R5341 8.6MOhms / 0
-R5342 2.26k / 2.2k
-R5215 257k / 750k
-R5216 196.7k / 255k
-R5230 0 / 0
-R5240 0 / 0
-R5275 4.9 / 4.7
-R5261 0.8 / 1
-R5262 0.8 / 1
 
2informaticos

2informaticos

Administrator
Staff member
PPBUS_AON and 3V8_AON fluctuate in same rythm as USB meter?

Why did you post two readings for each resistor?
Small value resistors can be checked onboard.
For high resistance, must unsolder one pin and check the resistor disconnected from its circuit.
 
E

EcWeb.L.

New member
Yes , PPBUS_AON and 3V8_AON fluctuate in the same rythm.

Two readings was to compare "My Value" / "schematics value" , my bad if it was misleading.

Do you have any tip on how to desolder these resistors from the board ? I've done a few ICs in the past but i can't get these little resistors out.
I've been on them with hot air set to 390 celcius / 30 airflow for quite some time but i can't get them off and i don't want to stay for too long risking to burn stuff .
 
E

EcWeb.L.

New member
Thanks! Applying leaded solder worked.

I can confirm all resistors are good , PPBUS_AON and 3V8_AON are still fluctuating in the same rythm as the voltmeter.
 
2informaticos

2informaticos

Administrator
Staff member
Check diode mode on the coils from all secondary power supplies.
Do the same for the outputs from page 39.
 
E

EcWeb.L.

New member
These are the coils i've tested .
L5230
-CHRG_PHASE1 0.499 OK


L5800-L5820-L5840

-PP3v8AON_VSw1 0.364 OK

-PP3v8AON_SW2 0.364 OK

-PP3v8AON_SW3 0.366 OK

LC320

-P5v_s2 0.312 OK

LC710

-P3v3_s3 0.287 (this one was suposed to be 0.423 according to the reference table)


OUTPUTS from page 36 :
1 PP3V3_AON 0.414 OK
2 PP1v8_AON 0.507 ( supposed to be 0.440 so i guess it's ok)
 
2informaticos

2informaticos

Administrator
Staff member
I said 39, not 36; there are UC810/20 to check.

What about all coils around U8100 and U7700?
Also check at pages 35, 86 & 87.
 
E

EcWeb.L.

New member
These are the readings .

U8100 area

-L8100
PPVDD_PCPU_AWAKE 0.032 OK
-L8110
PPVD_GPU_AWAKE 0.063 OK
-L8120
PPVDD_SOC_S1 0.049 OK
-L8230
PP1V8_s2 0.330 OK
-L84E0
PP1V4_LDO_PREREG 0.286 OK
-L8290
PPVDD_DCS_S1 0.270 OK
-L8280
PPVDD_DISP_S1 0.202 OK
-L8271
PPVDD_CPU_SRAM_AWAKE 0.241 OK
-L82B1
PPVDD_ECPU_AWAKE 0.121 (supposed to be 0.075)


U7700 Area

-L77A0
PP0V6_S1_VDDQL 0.147 OK
-L7741
PP1V06_S2SW_DRAM 0.044 OK
-L7750
PP0V764_S1_SRAM 0.233 OK
-L77D0
PP1V25_S2 0.252OK
-L77C0
PP0V88_S1 0.314 OK
-L7760
PP2V5_AWAKE_NAND 0.385 OK
-L7800
PP3V8_AON_SPMU_ISNS_VIN 0.346 OK



Page 39 outputs:

-PP3V3_S2 0.287 (this one was supposed to be 0.423 according to the reference table)
-PP3V3_S2SW_SNS 0.521 OK
-PP1V8_S2 0.345 OK
-PP1V8_S2SW_VDD1 0.392 OK

Page 35 Outputs

-PP1V4_LDO_PREREG 0.286 OK
-IPD_PWR_EN 0.376 OK
-PP1V8_AON_MPMU 0.523 OK
-TPAD_KBD_WAKE_L 0.375 OK
-P5VS2_PWR_EN_RC 0.374 OK
-LCD_PWR_EN 0.372 OK
-UPC_PMU_RESET_1V8 0.374 OK
-PP1V8_AON 0.516 OK

Page 86 :

JT710
-MIPI_DFR_CLK_CONN_FILT_P 0.404 OK
-DFR_DISP_VSYNC OL OK
-MIPI_DFR_CLK_CONN_FILT_N 0.424 OK
-DFR_1V8_DISP_TE 0.822 OK
-MIPI_DFR_DATA_CONN_FILT_P 0.430 OK
-DFR_1V8_DISP_INT 0.607 OK
-PP3V3_AWAKE_DFR 0.590 OK
-DFR_1V8_DISP_RESET_L 0.586 OK
-PP1V8_AWAKE_DFR 0.520 ( should be 0.427 )
- I2C_DFR_RES_SCL 0.614 OK
- I2C_DFR_RES_SDA 0.617 OK

JT700
-TP_DFR_TOUCH_PANEL_DETECT OL OK
-DFR_LID_OPEN_L OL OK
-DFR_DISP_VSYNC OL OK
-TP_DFR_TOUCH_RSVD OL OK
-SPI_1V8_DFR_MISO 0.590 OK
-SPI_1V8_DFR_CS_L 0.509 OK
-SPI_1V8_DFR_CLK 0.553 (should be 0.478)
-SPI_1V8_DFR_MOSI 0.553 (should be 0.478)
-DFR_1V8_TOUCH_INT_L 0.820 OK
-I2C_DFR_RES_SCL 0.615 OK
-DFR_1V8_TOUCH_CLK32K_RESET_L 0.547 OK
-I2C_DFR_RES_SDA 0.618 OK
-DFR_1V8_TOUCH_RESET_L 0.610 OK
-TP_DFR_TOUCH_ROM_WC OL OK
-PP1V8_AWAKE_DFR 0.520 OK
-PP5V_S2_DFR_FILT 0.311 OK

Page 87 outputs:

UT820
-SPI_1V8_DFR_CS_L 0.509 OK
-DFR_1V8_TOUCH_CLK32K_RESET_R_L 0.506 OK

UT830
-SPI_1V8_DFR_MOSI 0.550 (should be 0.478)
-SPI_1V8_DFR_CLK 0.550 (should be 0.480)

UT860
-SPI_DFR_MISO 0.343 OK

UT880
-DFR_DISP_TE 0.342 (i don't have reference)
-DFR_1V8_DISP_TE 0.821 OK

UT890
- DFR_TOUCH_INT_L 0.342 (i don't have reference)
- DFR_1V8_TOUCH_INT_L 0.819 OK
 
E

EcWeb.L.

New member
I took the reading on the side opposite to uc710 , to be sure i've checked again and it shows on both sides.
I'don't know if it makes a difference but it starts from 0.325 and rapidly goes to 0.290/0.287.
 
2informaticos

2informaticos

Administrator
Staff member
I supposed LC710 is lifted out, that's why I asked.
You can't get diferent readings, if the coil is in place.
 
E

EcWeb.L.

New member
It's mantaining 20v for about 20 seconds , amps back and forth up to 650mA . Then back to 5v and it tries again.
Seems like the boot sequence starts. Am i right?
 
E

EcWeb.L.

New member
The third photo in the first post i've made is this area.
I've now cleaned the area with alcool but there were some traces of dry wine and a mild corrosion on uc710 , pin 7-6-5-4 ( a bit of green can also e seen from the photo)
 
You must log in or register to reply here.
Top