Any history available?
What about 3V8_AON and U8100's LDOs?
What about 3V8_AON and U8100's LDOs?
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820-02443 - No power 5V 0.010A
- Thread starter joesklar
- Start date
I originally replaced the screen. Since replaced, sold on eBay. The customer returned it after 1 month, when I got it back it is in this state. There were no known issues with the board.
3V8_AON - 3.8V
I'm not sure what to probe around U8100. What is an LDO? If you can tell me what to test I can provide the readings.
Many thanks
3V8_AON - 3.8V
I'm not sure what to probe around U8100. What is an LDO? If you can tell me what to test I can provide the readings.
Many thanks
Low Drop Output (LDO) rails are clearly marked on pages 42 (Master PMU) & 38 (Slave PMU).
BTW, don't bother with the ones marked "NC" (Not Connected)!
BTW, don't bother with the ones marked "NC" (Not Connected)!
Thanks for the explanation!
Here are the voltages I think I have them all covered.
U7700:
PP1V8_S2 - 0.3-0.4V fluctuating
PP1V2_S2 - 0.3-0.4V fluctuating
PP3V8_AON_SPMU_ISNS - 3.8V
PP1V5_AON_VCORE_SPMU - 1.5V
PP1V2_AON_SPMU - 1.2V
PP1V8_AON_SPMU - 1.8V
PP1V2_AWAKESW_BLC - 0.0V
PP0V72_S2_VDDLOW - 0.140 - 0.170V fluctuating
U8100:
PP3V8_AON_MPMU_ISNS - 3.8V
PP0V8_S2_CLVR_VDDDIG - 0.200 - 0.240 fluctuating
PP3V3_AON - 1.7 - 1.9V fluctuating
PP1V8_S2SW_CLVR_VDDC1_LDO - 0.380 - 0.460V fluctuating
PP3V3_S2 - 0.9 - 1.1V fluctuating
PP1V2_S2 - 0.360 - 0.460V fluctuating
Here are the voltages I think I have them all covered.
U7700:
PP1V8_S2 - 0.3-0.4V fluctuating
PP1V2_S2 - 0.3-0.4V fluctuating
PP3V8_AON_SPMU_ISNS - 3.8V
PP1V5_AON_VCORE_SPMU - 1.5V
PP1V2_AON_SPMU - 1.2V
PP1V8_AON_SPMU - 1.8V
PP1V2_AWAKESW_BLC - 0.0V
PP0V72_S2_VDDLOW - 0.140 - 0.170V fluctuating
U8100:
PP3V8_AON_MPMU_ISNS - 3.8V
PP0V8_S2_CLVR_VDDDIG - 0.200 - 0.240 fluctuating
PP3V3_AON - 1.7 - 1.9V fluctuating
PP1V8_S2SW_CLVR_VDDC1_LDO - 0.380 - 0.460V fluctuating
PP3V3_S2 - 0.9 - 1.1V fluctuating
PP1V2_S2 - 0.360 - 0.460V fluctuating
Check PMU_VDDHI behavior.
Also check diode mode to ground on U8100's missing LDOs; disconnect any power first.
Also check diode mode to ground on U8100's missing LDOs; disconnect any power first.
2.58V at PMU_VDDHI is good enough; if you don't detect any drop on it.
I asked about its behavior just to confirm if is stable.
In this case, all U8100 LDOs should also be stable.
You may need to replace it.
I asked about its behavior just to confirm if is stable.
In this case, all U8100 LDOs should also be stable.
You may need to replace it.
Last edited:
Thanks for the feedback.
I have never replaced a BGA chip this large before. Even if I could perform the work, where can the chip be sourced from? Does it need to come from a donor board or can it be ordered online?
In your experience is specialised equipment needed or can it be done with a standard microsoldering set up?
Thanks
I have never replaced a BGA chip this large before. Even if I could perform the work, where can the chip be sourced from? Does it need to come from a donor board or can it be ordered online?
In your experience is specialised equipment needed or can it be done with a standard microsoldering set up?
Thanks
Such chip replacement, needs good practice.
Is very easy to damage the chip, even the mainboard.
14" and 16" models have interchangeable PMUs.
Is very easy to damage the chip, even the mainboard.
14" and 16" models have interchangeable PMUs.