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A2337 820-02016 5V 450mAh Liquid Damage

S

SolderFungus

New member
Hi. This is my first post. I have limited experience with the M series of MacBooks. I consider myself decent at soldering but I lack experience when it comes to more advanced motherboard troubleshooting. I hope I can learn something from all of you! Thank you.

I have a 820-02016 with liquid damage.
Getting 5V at 450mAh after replacing one of the CD3217 chips.
I have a Uni-T UTi120B thermal cam but I am not able to see any hot spots

I found a deviating value on PPVDD_SOC_S1. Broadview PDF tells me this is a .86V line. I do not believe I can inject voltage here and the resistance seems to be to high for that anyways. Please correct me if I'm wrong.
I'm not sure what the next troubleshooting should be. Any Any suggestions would be greatly appreciated.



From repair.wiki on the A2337 :
1713096229857.png
 
2informaticos

2informaticos

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

Did you change the CD3217 chip with one from donor board same model (and same position)?
What about PPBUS_AON and 3V8_AON voltages?
 
S

SolderFungus

New member
Thank you for the warm welcome!

I took the CD3217 from an A2179. Are they different from each model? I might have made a big mistake! o_O
The chip was placed with the dot facing in the same configuration as the image I provided under.
The motherboard is in the office. I will measure and rapport the voltages for PPBUS_AON and 3V8_AON provide the readings ASAP.
Thanks again, 2informaticos :)

1713120031396.png
 
S

SolderFungus

New member
PPBUS_AON 1V D 0.500
3V8_AON 0V D 0.449

One of the CD3227 was cycling different on the UDB-C meter.
I forgot one step.

After replacing the CD32 both chips were cycling at 5V 30mah.
I then reflowed UD550 because it had corrosion on it and that is when the amperage jumped to .450mAh.
I completely forgot that I reflowed UD550. Sorry about that.

I do not have a donor board available. I might have to put this board rep on hold until I can source a donor board.
I didn't know that CD32s were locked to one specific motherboard. This is valuable intel.
Thank you so much for the help so far.
 
2informaticos

2informaticos

Administrator
Staff member
PPBUS_AON is the first voltage to get on the MLB.
And U5200 can do that with just 5V on input.
Remove F5200 and check C5254 voltage.
 
2informaticos

2informaticos

Administrator
Staff member
Yeah, Main Logic Board.

So you have a problem outside of charger circuit.
Check diode mode to ground on all secondary power rails.
 
S

SolderFungus

New member
Does 12.3V from ISL mean that the CD32 charging circuit is operational?


Are the U8100 and U7700 the PMU BUCKS?


PP3V8_AON 0.338
PPBUS_5VS2 0.505
PP5V_S2 0.256
PP3V3_S2 0.426
PP3V3_AON 0.500
PP1V8_AON 0.464
PP1V8_S2SW_VDD1 0.402
PP3V3_S2SW_USBC0 0.450


Page 32 PMU: MASTER INPU PWR & BUCKS

PPVDD_PCPU_AWAKE 0.034
PPVDD_GPU_AWAKE 0.037
PPVDD_SOC_S1 0.040


Page 28 PMU: SLAVE INPUT PWR & BUCKS

PP1V06_S2SW_DRAM 0.063
PP0V764_S1_SRAM 0.246
PP2V5_AWAKE_NAND 0.354
PP0V6_S1_VDDQL 0.160
PP0V88_S1 0.281
 
Last edited:
2informaticos

2informaticos

Administrator
Staff member
"Does 12.3V from ISL mean that the CD32 charging circuit is operational?"
No.
U5200 can generate this voltage with just 5V input; before CD3217 chip switches to 20V.

If you resolder F5200, PPBUS_AON still not present?
Be sure the fuse is good.
 
S

SolderFungus

New member
Hi. Yes the fuse is fine. 0.01ohm resistance. I replaced it and even bridged it with copper wire just to try. The result is the same.
Voltage drops to 1V after resoldering fuse.
 
S

SolderFungus

New member
Alright, hmmm. Should I maybe investigate components that use PPBUS_AON or the ones that are needed to create PPBU_AON?
Chicken or egg situation. Tricky stuff.

PPVDD_SOC_S1 has lower resistance to GND. (marked with red square at the top of this thread)
Is this not a possible reason?
 
2informaticos

2informaticos

Administrator
Staff member
"components that use PPBUS_AON"
Of course, the problem appears only when F5200 is soldered.
PPBUS_AON is generated, without the fuse.

"PPVDD_SOC_S1 has lower resistance to GND"
May be normal; compare exact value with good board.
 
ipetro

ipetro

Member
SolderFungus said:
Thank you for the warm welcome!

I took the CD3217 from an A2179. Are they different from each model? I might have made a big mistake! o_O
The chip was placed with the dot facing in the same configuration as the image I provided under.
The motherboard is in the office. I will measure and rapport the voltages for PPBUS_AON and 3V8_AON provide the readings ASAP.
Thanks again, 2informaticos :)

View attachment 61597
Click to expand...
The only difference between СD3215 and СD3217 is that one in a pair of СD 3217 is a programmable chip (А-programmable, В-slave), so in no case can it be confused and it is better to mark it right away! I don’t think the board models matter, I changed from А2179 to А2338 and everything works! The main thing is not to mix it up and it’s better to change it in pairs! but I could be wrong, this is my experience and my mistakes!
 
2informaticos

2informaticos

Administrator
Staff member
You are close, but no really like that.
Some CD3217 chips are programmed for specific position (OTP).
Other have external strap to ground.

Of course, you can't mix them.
Mark any chip before extract it; board model and position.
A2141 and A2251 give many problems with them.
 
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