1. xstre pwnsx

    OP xstre pwnsx GBAtemp Regular
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    I purchased a nintendo switch to repair; I came here to ask for advice about what may be wrong with it.
    Board: PWB/ AU/ CHN HAC-CPU-01

    Fuse has continuity
    The battery does not charge, I plugged it into the usb c charger w/ battery and left it for 30 minutes result being battery went from 4.06v to 4.02v.
    There is a shorted capacitor on pin 18 of the MT CHIP

    Voltage Readings (From Caps)
    BQ CHIP
    Pin1: 14.97 V (W/ Charge + Batt plugged in)
    MT CHIP
    Pin 5: 3.29V (W/Charge + Batt plugged in)
    Pin 6: 3.30V (W/Charge + Batt plugged in)

    Voltage Readings (From Testpads)
    Cluster K (Batt, Batt+ Charger, All unplugged)
    Testpad 1: 0V, 0V, 0V
    Testpad 2: 0V, 0V, 0V
    Testpad 3: 0V, 0V, 0V
    Testpad 4: 0V, 0.1V, 0V
    Testpad 5: 0V, 0.92V, 0V
    Testpad 6:0.06V, 14.96V, 0.03V
    Testpad 7:0.05V, 14.97V, 0V

    Cluster L (Batt, Batt+ Charger, All unplugged)
    Testpad 1: 3.61V, 3.60V, 0V
    Testpad 2: 0V, 0V, 0V
    Testpad 3: 3.61V, 3.61V, 0V
    Testpad 4: 0V, 0.1V, 0V
    Testpad 5: 0V, 0V, 0V
    Testpad 6: 0V, 0V, 0V

    Any idea what's wrong?
     
  2. LIY2012

    LIY2012 Member
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    According to the datasheet, the MT pin 18 is the 3.3v rail. I'm not sure how that would affect battery charging though.
     
  3. xstre pwnsx

    OP xstre pwnsx GBAtemp Regular
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    2 of the large capacitors under the CPU are shorted....
     

    Attached Files:

    Last edited by xstre pwnsx, Jun 28, 2020
  4. Mightyjebus

    Mightyjebus Member
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    check pins 35 and 37 on the M92 IC. you should see a difference between the 2 with the charger plugged in. turn the charger 180 degrees and see if the reading swap over.
    This will tell you if the switch is seeing the charger plugged in and it recognised the orientation.

    Also disconnect the battery and plug the charger in and see if you are getting a voltage on the battery connector pins (left 2 pins)
     
  5. xstre pwnsx

    OP xstre pwnsx GBAtemp Regular
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    @Mightyjebus

    Pin35: ~0.94V ----> Charger rotated 180 degrees Pin 35: ~0.11V
    Pin37: ~0.11V ---> Pin 37: ~0.93V

    Fluctuated from (0.08V to 0.11V)
    Fluctuated from (0.93V to 0.94V)

    Battery Connector on PCB
    Pin1 (from left): ~3.4V
    Pin 2 (from left): ~3.4V

    Fluctuated from 3.4V to 3.8V
     
  6. xstre pwnsx

    OP xstre pwnsx GBAtemp Regular
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    Some good news I removed that cap on m92 pin 18 and the pads don't short... so the capacitor was bad! would anyone happen to know where I could pluck one off a donor board to replace it with (minus the exact same spot as I've taken that one already)
     
  7. xstre pwnsx

    OP xstre pwnsx GBAtemp Regular
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    Also is there a way to tell which emmc module goes with which motherboard? I seem to have mixed two modules up... or rather what happens when you plug the wrong emmc module in.
     
    Last edited by xstre pwnsx, Jul 1, 2020
  8. SheriffBuck

    SheriffBuck Advanced Member
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    Great suggestion. An even better option is to check whether the orientation is being properly detected in the M92. Pin 11 (Orient) will flip between 1.8v and 0v depending on connector orientation. I've had an M92 that was getting the CC lines properly, but refusing to select Orient properly.
     
  9. LIY2012

    LIY2012 Member
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    Be careful. If you try to boot with the wrong eMMC and it's on a newer firmware, it will happily burn your fuses and make it so neither will boot. If they were both on the same firmware, you should be able to try them one at a time, and the correct one will boot. If you're unsure, I would recommend trying to open up the partition in HacDiskMount and trying to read the partition. If it accepts your BIS key, it's the correct one for that switch. If the BIS keys are wrong, it's the wrong one.
     
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  10. SheriffBuck

    SheriffBuck Advanced Member
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    Easy thing to do. Label your board bits before you dismantle! There are some different theories on this forum. For certain your Switch will not boot with the wrong EMMC fitted. The EMMC is encrypted using a unique keyset held within the TEGRA (they are paired in production), so basically the Switch cannot un-encrypt the boot drive and stops. Some have said that you burn fuses, however I'm not sure that is the case as there is no firmware to read that would trigger it (unless some elements of the EMMC are unencrypted?)

    Thoughts anyone else?
     
  11. LIY2012

    LIY2012 Member
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    According to switchbrew, the boot0 and boot1 areas as well as the 6 BCM packages are not encrypted with console specific keys. I believe the code that checks the fuses is in the boot0 partition.
     
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  12. xstre pwnsx

    OP xstre pwnsx GBAtemp Regular
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    Thanks for all the advice.. say I've made the mistake of plugging in both emummc modules and tried to boot at some point, would I not still be able to get the unit into RCM mode (They are both unpatched)...
     
  13. LIY2012

    LIY2012 Member
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    Yes, if they are both unpatched, it would be a pretty easy fix. If one is patched, and you don't have the keys, you could end up with a brick.
     
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