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Macbook A1989 820-00850-A stuck at 5.09V 0.89W and 0.16 amp

S

sourcensolutionsonline@gm

Member
This Macbook Came in when i connect to USB amp meter , its stuck at 5.09V 0.89W and 0.16 amp , I proceeded to open it to check the CD3215 Chips and found at UB300 CB300 was full shorted to Ground , I managed to remove the CB300 and replaced it , I plugged again my USB AMP METER and the Behaviour remains the same , I tested CB300 again and resistance value to ground was normal .366 OHM , I Thought it might've been CB300 Was probably defective so i went ahead and changed it to a new one and behaviour still the same , So what i did i changed all the 4 CB3215 Chips to new ones and the behaviour never changed I have measured R7020 and my 5v is there, when I checked the LDOS

U3100
PP1V8_UPC_XB_LDOD = 0.020
PP1V1_UPC_XB_LDO_BMC = 0.448
PP3V3_UPC_XB_LDO = 3.350
PP1V8_UPC_XB_LDOA = 1.813

U3200
PP1V8_UPC_XB_LDOD = 1.796
PP1V1_UPC_XB_LDO_BMC = 0.023
PP3V3_UPC_XB_LDO = 3.355
PP1V8_UPC_XB_LDOA = 1.804

UB300
PP1V8_UPC_XB_LDOD = 1.815
PP1V1_UPC_XB_LDO_BMC =0.021
PP3V3_UPC_XB_LDO = 3.216
PP1V8_UPC_XB_LDOA = 0.23

UB400
PP1V8_UPC_XB_LDOD = 1.815
PP1V1_UPC_XB_LDO_BMC =0.230
PP3V3_UPC_XB_LDO = 3.216
PP1V8_UPC_XB_LDOA =1.796


I was checking on the forum and seeing that someone else that you are helping is having my same issue , another thing , since those chips come with strong underfill while removing the CD3215 I lost all the NC's pads and they left no trace at all i am not sure if they are NOT CONNECTED or please advice

Thank you
 
2informaticos

2informaticos

Administrator
Staff member
NC stands for Not Connected, so no problem if these pads have gone.
Be sure all other pads have good trace.

You've got some low readings on U3100/200 and UB300.
However, recheck all LDOs in correct manner; diode mode with red probe at ground ALWAYS.
 
S

sourcensolutionsonline@gm

Member
I got it fixed, I went back to double check as you said , I found CB404 Was giving me OL , So I reflow the UB 400 And everything went in smoothly fine , thank you so much for your support , the other guy should just change the CD3215 And he should be all good to go.
 
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