Switch will not recognize that Joycon is attached, and cannot sync new joycons

Discussion in 'Switch - Console, Accessories & Hardware' started by Devon093, Aug 12, 2019.

  1. Devon093
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    Devon093 Member

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    This is a repair for a family friend who im quite confident did not perfom any homebrew on the console. Both joycons are connected, they both charge and also the switch shows the graphic on each side of the screen that i attached a joycon but the Left Joycon doesnt not say it is 'attached' to the switch. As a result i cannot sync new joycons to the system. I have already replaced the rail and there was no change with the issue. Help would be appreciated!

    (If by chance homebrew could have something to with this, please let me know and ill find out for sure from them. Thanks in advance.)
     

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  2. EmulateLife

    EmulateLife GBAtemp Psycho!

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    The only way homebrew might have something to do with it is if they were using a homemade jig like a paperclip to access RCM and it could have shorted a pin.

    But that is only on the right joycon it would have no effect on the left. Impossible left joycon was effected by homebrew unless they had no idea what they were doing and tried entering RCM through the left joycon (which wouldn't work)
     
    Last edited by EmulateLife, Aug 12, 2019
  3. Devon093
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    Devon093 Member

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    Thanks for the reply, i didn't think homebrew would do this. Has to be an on board component i assume just wish i had an idea where to look
     
  4. EmulateLife

    EmulateLife GBAtemp Psycho!

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    I didnt say homebrew did this I said messing with the pins on the joycons which is required to enter homebrew might have if it was the right side railing.
     
  5. Devon093
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    Devon093 Member

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    Sorry if I confused ya, I'm aware of what you meant. Which means that the issue is likely a component on the board i just need to locate it.
     
  6. Devon093
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    Devon093 Member

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    Any ideas from anyone? I tried looking for shorts in the connector for the joycon but they all seem normal. Anyone know what IC controls them?

    *fancy bump
     
  7. matias3ds

    matias3ds GBAtemp Advanced Maniac

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    I have the same problem when i connect both of the joycons only one of them can charge at the time . i already resync them but the problem is when i connect them to the switch .
    I dont know what the problem could be .
     
  8. Agilato

    Agilato Advanced Member

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    I have guess that there are two "MAX" chips responsible for joy-con paring each of them have power circuits also, they damn hard to replace: they are BGA, Open crystal and there is so many plastic connectors around them... you have to preheat the board... i tried to do it like 7 times, attempts were not successful.... I noticed that in to the new revision of the switch they merged two chips in one, may be that will make it easier to repair....

    One thing i should tell to people who experienced this issue DO NOT RESET CONSOLE TO FACTORY, i have one console that i am not able to pass configuration screen because of paring issue.
     
    Last edited by Agilato, Aug 16, 2019
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  9. Devon093
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    Devon093 Member

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    I am going to look into the ICs you are reffering to, and maybe try a swap. If im unsuccessful i assume the functionality will not change hopefully.

    And yeah i figured that too since it never know the joycon is connected to the console so youd be stuck at initial set up.. Ill take a look soon and update!

    — Posts automatically merged - Please don't double post! —

    The issue youre describing seems a bit different, have you tried plugging the switch into its charger when charging joycons? The switch will only charge joycons when there is enough battery, and only charge the joycon with less battery. Try plugging them both in (make sure they arent fully charged), and then plug the switch into the charger and see if that helps the joycons
     
  10. SolidSnakeUk89

    SolidSnakeUk89 Advanced Member

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    that seems to be MAX77621AEWI
    and also I see tiny mosfet around the connectors, seem to be 6pin, I have 2 boards here and one of the boards, both of these mosfet show letters "ZBL" and the other board just say "MX".. not sure how to read those LOL seems Nintendo didn't use the same parts for all of their boards or it could be some weird serial number but Im sure these mosfet are involved in power delivery to the joycon batteries. I would need to test one to see what the gate voltage is when you plug a joycon, interesting excercise I may give it a go in a couple of days.
     
  11. Devon093
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    Devon093 Member

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    I reallllly hope it is not the MAX77621AEWI, I don't think im capable of swapping it.

    Perhaps ill try one of those mosfets and just hope for the best, and if not maybe those smalled BGA chips Agilato mentioned
     
  12. Devon093
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    Devon093 Member

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    Fixed! Swapped one of the 6 pin chips marked "PU"

    Picture provided!
     

    Attached Files:

  13. SolidSnakeUk89

    SolidSnakeUk89 Advanced Member

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    awesome to hear! - well done mate, how did you come to the conclusion to replace that? if you dont mind me asking.. :P
     
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  14. Devon093
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    Devon093 Member

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    It was honestly a long shot, since the switch was charging the joycons i wanted to try and avoid things i knew were power related.

    I noticed that the PU chip i replaced and the other one in the picture which is marked MX are on both ends of the board each on the opposite side of the joycon clips.

    I focused there and just chose one to replace and i got lucky :)

    EDIT: Seems like the PU chip i swapped is marked ZBL on your boards looking back
     
    Last edited by Devon093, Aug 17, 2019
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  15. SolidSnakeUk89

    SolidSnakeUk89 Advanced Member

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    yes those are either little dc~dc converters or some sort of buck converters and the markings seem to be some serial number, all the boards I check they say something different LOL

    good to know!!!
     
  16. Devon093
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    Devon093 Member

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    So... This is awkward. I had a friend help me with the reassembly and ive encountered a new problem. The unit appears to be not displaying video in handheld mode. The back light is coming on, the unit is booting since i can use the touch screen, and also outputs correctly through docking station. However in handheld mode it is not showing video. I have checked the LCD cable and the connector and both seem okay. Any advice?
     
  17. SolidSnakeUk89

    SolidSnakeUk89 Advanced Member

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    The lcd flex cable and connectors are really delicate to the point that I have a special tweezers I have covered with foam to prevent scratching, check with microscope that there are not ripped connections and check the tiny pins inside the lcd connector. The youtuber mymatevince has a video where he messes up the connector and shows how to repair it


    If that is all good, There are 4 test pads on top of the LCD connector, are you getting any voltage there.. ?

    I don't have a switch closely right now but I think the LCD turns on with the 3v power rail.. I need to double check.

    Try probing around for
     
  18. Devon093
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    Devon093 Member

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    THanks for continuing to reply,

    I have fixed som bent pin LCD ribbon clips before, and also replaced one entirely. I checked for bent pins

    I have checked the test points near the LCD, one of them is ground. Out of the other 4 2 pins have 1.8V, which i also tested on another board and that seems to be the same.
     
  19. SolidSnakeUk89

    SolidSnakeUk89 Advanced Member

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    hmmm is getting interesting!! lets go back to sqare one.

    we now this is the switch that has had a mosfet replacement to make the joycons work isnt it? - can you check for shorts around that? (not likely but could be some power derivation.. im pretty much shooting to the sky with this one tho!)

    if I had a console that does not display on handheld but it works on doc and touchscreen is responsive I would do the following:
    get the board out and plug it into a known good assembly (with known good battery, lcd, ribbon cables etc...) and test if works there.. - if does, then take an LCD screen, plug the mobo in its own assembly and just use a separate LCD to see if isolating that may be the issue.
    if that doesn't work then we know the mobo is bad.. so I would start checking for voltages on all of the known pads. I have attached the document I have with a big recollection of posts and pictures of the mobo including voltages and test pads description. I would see if all matches and try to isolate the problem to one "section" of the mobo.
    I know this is going to sound repetitive.. but PI3USB and M92 chips have a big role to play in power and video delivery so I would try swap them and keep them anyway in case they were good.. power & voltage levels is controlled by M92T36 & PI3USB multiplexes the signals (ie switches the lines to do different things and I think one of those things may be switching voltage to the LCD connector)

    I was having a look at one of the donor boards and I notice a bunch of what appears to be Panasonic EXC24CS inductors or equivalent (like the ones behind PI3USB) and I think these may play a similar role than the other ones behind PI3USB although those are used for the dock image.. these here are use maybe for the LCD image?.. could be that one of them is crossed or grounded?
    upload_2019-8-22_0-34-34.


    other than this.. Im starting to run out of ideas! LOL
    maybe is time to call the big boys !!! @mattytrog are you around? can we summon you to enlighten us? :D

    — Posts automatically merged - Please don't double post! —

    OMG Im going to double post!! -- but need to add this... I just noticed some diodes behind the LCD connector.. check that they are working well and not become a resistor or a wire!!
     

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  20. mattytrog

    mattytrog You don`t want to listen to anything I say.

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    Cheers for the tag @SolidSnakeUk89

    Every pin needs to be sat correctly in the FPC connector.

    They are very easily damaged. Did one only yesterday.

    Best way to replace, is to heat it up from the underside of the board. Around 370 degrees. Will lift off when ready.

    Otherwise you will melt the BTB stacking connector for the emmc & fan / switch FPCs

    Easily fixed using this method.

    Regarding your joycon pairing issue...

    Lets start from the top...

    Have you tried another joycon? If so same result?
     
    SolidSnakeUk89 likes this.
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