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mon2
mon2
Badcaps Legend
Last Activity: Today, 11:03 AM
Joined: 12-15-2019
Location: Windsor, Ontario
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  • What is the voltage to ground of [B]ALL_SYS_PWRGD [/B]? Is it pulsing ?

    reference:
    [URL="https://boards.rossmanngroup.com/threads/820-00165-a-pm_slp_s4_l-missing.38016/"]820-00165-A - PM_SLP_S4_L missing | Rossmanngroup Forums[/URL]​What is the voltage to ground of [B]ALL_SYS_PWRGD [/B]? Is it pulsing ?

    reference:
    [URL="https://boards.rossmanngroup.com/threads/820-00165-a-pm_slp_s4_l-missing.38016/"]820-00165-A - PM_SLP_S4_L missing | Rossmanngroup Forums[/URL]​
    What is the voltage to ground of [B]ALL_SYS_PWRGD [/B]? Is it pulsing ?
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  • mon2
    started a topic Asus X1403ZA Boardview file

    Asus X1403ZA Boardview file

    Attached....
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  • Review the topside markings of the DCin mosfets and also the nearby charger IC. Post each of these details for a review.

    Post pics of your logic board where you are noting the first mosfet to save on some time against the review of the boardview file.

    From the BV review,

    PU8901[B] BQ24800RUYR[/B]//TI is the charger IC.

    PQ8901 & PQ8902 DCin mosfets are the suspects. Carefully flux and remove the 2nd DCin mosfet.

    Check this removed mosfet after it is cool and on your work table. Likely it is defective.



    ...
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    Last edited by mon2; Today, 10:00 AM.

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  • Try a DFU restore.

    reference:
    [URL="https://repair.wiki/w/MacBook_Air_A1932_Not_turning_on,_missing_P5VG3S_EN_signal_repair"]MacBook Air A1932 Not turning on, missing P5VG3S EN signal repair - Repair Wiki[/URL]​

    Continue to post your updates here.Try a DFU restore.

    reference:
    [URL="https://repair.wiki/w/MacBook_Air_A1932_Not_turning_on,_missing_P5VG3S_EN_signal_repair"]MacBook Air A1932 Not turning on, missing P5VG3S EN signal repair - Repair Wiki[/URL]​

    Continue to post your updates here.
    Try a DFU restore.
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  • Continue to use USB-C port since it can negotiate the PD contract for 20v.

    What is the voltage to ground of [B]P5VG3S_EN_DLY [/B]? Some trouble here if the output rail is @ 0 ohms to ground. Checking if the enable signal is present for this power rail or not.

    What is the voltage to ground of [B]PPBUS_G3H [/B]?Continue to use USB-C port since it can negotiate the PD contract for 20v.

    What is the voltage to ground of [B]P5VG3S_EN_DLY [/B]? Some trouble here if the output rail is @ 0 ohms to ground. Checking if the enable signal is present for this power rail
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  • If the current draw is a sudden fixed value then you will need to check the resistance to ground on the vbus rail on the usb type c connector. There may be a partial short on this leg of the circuit. Is the current draw the same value if the power cable head is flipped by 180 degrees? Do not inject such a high voltage till more is known about your case.
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  • You will have to carefully inspect the ICs where you applied the hot air. Often the pop is due to high heat applied quickly onto an IC that may have had some internal moisture. The high heat causes the ic to crack from the steam buildup or expansion. This is why ics are pre-baked for hours at a low heat temp to draw out the moisture over time. Then the dried ics can be soldered onto a fresh pcb during assembly time. So this ic may have a crack somewhere on its body.

    search for ‘popcorn effect in pcb assembly’ for more details.
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  • Suggest to use a lower resistance scale and measure this fuse again. Short your probes and you should read ~0 ohms. Measure the resistance to ground again at the fuse. If you read a '1' then the resistance is too high to measure and a higher meter scale should be used. Either way, you should have a lower resistance on this rail. At this time, you do not need to remove F7000 unless we can confirm there is a part that is shorted on this power rail.

    Next, with the meter in DC volts mode (20v or higher), measure the voltage to ground of [B]PPDCIN_G3H[/B].Suggest to use a lower resistance
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  • Remove all of the parts you are suspecting that are the not 100% like the original such as the keyboard backlight. Even the keyboard should be removed. Use the tweezers to perform the ON/OFF button activity to test again.
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  • Carefully measure the voltage to ground @ F7000 - check both sides. If the voltage is not in a normal range, power down and configure the meter into RESISTANCE mode. Remove all power / no battery. Measure the resistance to ground on each side of the fuse F7000.

    If the resistance to ground is low, carefully flux and remove F7000 fuse. Allow the board to cool and then measure the resistance to ground again on each side of the remove fuse PCB pads @ F7000.

    Which side of the removed fuse is with a low resistance? Post each measurement.
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  • Flux and carefully remove F7000 off the board with hot air. We need to determine which side of the fuse is with the short. Most likely it will be the downstream (consumer) side rather than the upstream (producer / ISL) side.
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  • remove all power. Check the resistance on each side of F7000....
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  • PU301 will output +3VALWP = +3VALW via PCB trace @ PJP302 if and only if (iff) EN1 enable signal (pin #12) is a logic '1'. EN2 signal is an enable for the LDO rail @ pin #17 = +3VLP.

    Repeat the same review for PU501 with EN1 (pin #12).
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  • Nothing special about the 4R7 resistor. Appears that this ISL is dead if VDDP is 0v....
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  • When diodes are stitched together like your previous post - the power supplies are being "OR'd" in the logic term sense. That is, if either of the power feeds from the backside (aka anode) of the diode is present, then that voltage will travel in the direction of the arrow head onto the cathode. Even better is that even if multiple power rails are present, only the highest voltage will reach the cathode without harm to the other voltage rails. As long as the diode is working, no one gets hurt. You cannot just tie multiple different potentials of voltages together without such protection....
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  • Sorry, my bad. [B]VDD [/B]is at 0 volts?? This will be an internal power rail. Can you confirm? The ISL may be defective. We can check in diode mode.

    Update - in addition to checking if [B]VDD [/B]is @ 0 volts, confirm the voltage to ground of the [B]VDDP [/B]pin # 8.

    Next, remove all power -> meter in resistance mode -> check the resistance across the resistor @ [B]PR1908[/B]. This should be ~5 ohms (use your lowest resistance scale on your meter to measure).Sorry, my bad. [B]VDD [/B]is at 0 volts?? This will be an internal power rail. Can you confirm? The ISL
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    Last edited by mon2; 02-23-2024, 03:29 PM.

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  • These are good readings. Remove all power. Meter in resistance mode. One meter probe on [B]ACOK [/B]pin #24 on the charger IC. Other meter probe on pin #18 on the charger IC. No power again during these resistance checks.

    What is the measurement? This is to confirm that the ~100k resistor is present as the weak pull-up @ PR1911.

    After this, check the voltage to ground of [B]AC_DIS [/B]@ PQ1906. If there is a high enough voltage on the gate of PQ1906, then this mosfet will enable and shunt the [B]ACOK [/B]pin to ground.These are good readings. Remove all power. Meter in
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  • Not yet. Need to check if the ISL chip is being powered. Only after it is powered, the ISL chip will monitor for a threshold voltage on the ACIN pin # 19. If this threshold voltage is met or exceeded, then ACOK will be a logic high. ACOK is an open drain pin and will only be a logic high provided that the resistor @ PR1911 is present and should be ~100k ohms AND the VDD voltage that is powering the ISL chip is present on pin # 18.

    So proceed to check the following voltages to ground on:

    [B]ACIN[/B] pin #19
    [B]DCIN[/B] pin #17 ; believe you have done this earlier...
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  • What is the voltage to ground of [B]ACOK [/B](pin # 24) on the charger IC @ PU1900? Measure very carefully and only if your meter probes are with a fine tip. You can also consider to measure this voltage at the solder blob shown as [B]PR1921 [/B]in the schematic.What is the voltage to ground of [B]ACOK [/B](pin # 24) on the charger IC @ PU1900? Measure very carefully and only if your meter probes are with a fine tip. You can also consider to measure this voltage at the solder blob shown as [B]PR1921 [/B]in the schematic.What is the voltage to ground of [B]ACOK [/B](pin # 24) on the charger IC
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  • Not directly familiar with this model but power delivery is the same across the USB Type C platforms.

    Would you have a USB Type C meter? What is the voltage and current draw by this logic board? Are you using a known good USB Type C power adapter? Have you tested with other power adapters?

    Remove all power -> meter in resistance mode -> measure the resistance to ground of the power rails on this USB Type C power delivery controller.

    A low resistance here is usually bad news.

    [ATTACH=JSON]{"data-align":"none","d...
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