Internal modchip - SAMD21 (Trinket M0, Gemma M0, ItsyBitsy M0 Express) Guide, Files & Support

Discussion in 'Switch - Tutorials' started by mattytrog, Jun 20, 2018.

  1. Hayato213

    Hayato213 GBAtemp Guru

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    Dec 26, 2015
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    I own 4 units with modchip from 4 different guys, I haven't seen really seen anyone putting proxy/glue on wire, I seen people put glue/epoxy on the shield part where the chip sit onto of , to keep it from moving, electical tape and kaptop is fine for keeping the wires from moving.
     
    Last edited by Hayato213, Aug 6, 2019
  2. smasha

    smasha Member

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    Aug 16, 2018
    Australia
    I've done a few switches for myself and mates too. I put double sided tape on the chip to secure it to the shield (to prevent any type of short) then epoxy on the chip to secure it to the shield as well. However i also dab a bit along the wires to secure them to the mainboard, preferably near the the solder joint if there's a nice spot for it, because I'm also OCD. The way I see it, it can't hurt and It helps to relieve any stress on the wire/connection. Also would help in scenarios if the switch gets dropped (most of my installs will be used by kids), in case of a bad solder joint the wire won't just pop off (again, OCD).
     
  3. mattytrog
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    mattytrog You don`t want to listen to anything I say.

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    Apr 27, 2018
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    Regarding the epoxy argument...

    In electronics, we use epoxy for "potting"... It is very very useful in scenarios that would be detrimental to the electronics... For example water submersion, or tamper resistance, or even to tuned circuits that you don`t want the end user to retune. But mainly for mechanical protection.

    In the old days, we used to use wax for potting and for "setting" things. Also for mechanical protection. Look at old radios from the 1980s.

    However, anything that generates heat this is of course not correct. If you have something that will be completely submerged, or you want hidden and tamper-proof, you apply epoxy to it.

    Samsung used to (still does?) use a kind of adhesive (not epoxy) to hold components in position prior to wave soldering. This adhesive wasn`t removed. Consequently, cooling and heating cycles condenses water vapour and this can enter the adhesive. Also this adhesive seems to "crystalise" over time and starts acting like a semiconductor, leading to a high impedance connection and upsetting tuned circuits by changing inductance / capacitance values. This can change reactance in that part of the circuit, giving you a bad time.

    If you don`t have any Kapton, you can use the 2-part epoxy and put just a tiny bit on the mask ONLY. Never on a component that generates heat. Never any epoxy that contains metal. Avoid the "super-fast-set" stuff. Never seems to completely go off.

    Equal parts of resin and hardener, mix really really well and just a tiny smart-looking "blob". Don`t pigeon-shit it all over the place... Less is more.

    We are talking the tiniest bit on the end of a toothpick.

    Epoxy doesnt flex a great deal. The shield is very shiny, so epoxy will eventually crack off(a bit like dried play-doh peeling off a plastic lid)

    Kapton is fine. Looks nice too. And in this particular application is preferred.

    Solder joints if soldered correctly will hold themselves within reason.

    I used to place a dab of epoxy in one go over the wires, above the m92t36 on the groundplane. But now I use kapton.

    If you do use epoxy, if using the black stuff, be careful as the black stuff CAN contain carbon. Carbon conducts as we all should know.
     
    Last edited by mattytrog, Aug 6, 2019
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  4. DenisTheManis

    DenisTheManis Newbie

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    Aug 2, 2019
    Germany
    Thanks a lot for all the advice. I guess I will have to open the switch up again. Because the tape flying in to the fan is definetely not something I would want :D
    As it was my first soldering project, I obviously don't have a lot of faith in my work, so I used the tape. I dont see why cables should fall off, but I still wanted to help out a bit, in the case the switch falls down or something like that.
    I also used rather inefficient paths for my cables. That's something I might have to revisit.
     
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  5. plasticninjaguy

    plasticninjaguy Newbie

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    Aug 7, 2019
    Australia
    Hi, sorry if I’m putting this in the wrong area but I’m getting desperate and I’m very new here.
    So I attempted this modchip install, I removed the motherboard to keep away from the battery and to get a better space to work with. After completeing all the soldering, I killed my trinket during micro-USB port removal, so I was forced to just kind of leave all of the wires that were going to be going to the trinket just kind of kapton taped to a non conductive surface.
    Anyhow, upon reassembly and powering on, all seemed to work fine, until I noticed the unit wouldn’t charge past 83%. I used the device until 15% then left it overnight and still nothing.
    Wondering if anyone knows what might commonly die (in regards to the charging circuit) when attempting all of the straps for the trinket m0 install.
    Thanks and sorry in advance for my kind of long post.
     
  6. mattytrog
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    mattytrog You don`t want to listen to anything I say.

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    Ok... Can we have a look at your install? Take some nice clear pictures of all areas where the straps are connected :)
     
  7. plasticninjaguy

    plasticninjaguy Newbie

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    Aug 7, 2019
    Australia
    Thanks Matty
    I forgot to mention I was using both alternate solder points, as I have hand tremors and these points seemed easier to pull off.
    EDIT: uploaded wrong photo lol
     

    Attached Files:

    Last edited by plasticninjaguy, Aug 7, 2019
  8. mattytrog
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    mattytrog You don`t want to listen to anything I say.

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    By the looks of it, you are using the "easy strip" winding wire. The lacquer melts when touched with a soldering iron?

    You have something shorted somewhere. It could be the usb strap having a direct path to gnd somehow.

    I'd strip it all out, see what is working and what isn't.

    If you have popped anything, it will be the bq24193 I'm guessing if not charging. The m92t36 is probably ok because it was running for a time.

    Use kynar wire instead. Those straps are probably well soldered but they are too long (particularly the joycon strap).

    The lacquer is broken somewhere is my guess.

    Feel free to send it in if you are struggling.

    But start from the beginning. Let's see what's popped and what isn't.
     
  9. plasticninjaguy

    plasticninjaguy Newbie

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    Aug 7, 2019
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    Ok I’ve been testing things to ground and it appears that the resistor just to the right of the USB disconnect strap is not in any way common with ground. I am not very familiar with the switch’s charging circuit, but all of the other resistors are grounded at one end. I tried a google, but I’m not too sure on how to test the two charging ICs (bq and m92) if you could bump me in the right direction I’d be highly appreciative.
    Thanks again Matty

    EDIT: Omg they’re all caps aren’t they.
     
    Last edited by plasticninjaguy, Aug 8, 2019
  10. mattytrog
    OP

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

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    Bq24193... Simple. Plug power source into usb, see if v goes up.

    M92t36... A good initial indication it is ok if you check pin 5 vcc-in. 5th pin down, left hand side. Next to the point we solder to for chip power.

    There could still be other faults in the chip... There are fets etc, but because it powered on I'm saying it's ok for the moment.

    Make sure you solder to the 3v point on the chip. Some people solder to the 5v point (ie to go through the regulator)

    That just adds (slight) overhead but if it fails short circuit, will be death to max77620.

    So ensure you connect to 3v. Get rid of the regulator if you like. Remove it completely from trinket.

    This is all theory of course. As long as you are getting steady readings with your resistors (I think they might be 10k from memory. Can't check at the minute) you should be fine.

    If you remove everything and still no charge, I'm guessing bq24193 dead. Easily replaced.
     
  11. plasticninjaguy

    plasticninjaguy Newbie

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    Aug 7, 2019
    Australia
    Ok last question. With this charging circuit, is it designed to kick in once the battery goes below a certain voltage threshold or does it work using some other detection method. Because I noticed at 83% the voltage on the battery rails was 4 volts and now at 12% it’s at 3.7.

    Thanks

    EDIT: well ok after a complete tear down and reassembly, as well at the removal of that awfully ghetto looking USB disconnect strap, the device appears to be charging again. I plugged in USB power and the voltage across the battery rails shot from 3.7 to 4, then I noticed the battery went from 12% to 21% over about 5 mins.
    Thanks again for all your time Matty, this has been a warm welcome to the GBATemp community.
     
    Last edited by plasticninjaguy, Aug 8, 2019
  12. mattytrog
    OP

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

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    No worries. The chip is controlled by i2c. Status can be read and commands sent and info received based on requirements in software. It is a smart little chip. Almost like a microcontroller in itself
     
  13. plasticninjaguy

    plasticninjaguy Newbie

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    Aug 7, 2019
    Australia
    Well, it's me again.
    So I ordered another Trinket M0 and retried the micro UBS port removal, with success. I installed the modchip successfully (I think) and when I power on the switch I see a flurry of lights. I went for the Dual Boot + SwitchBoot combo from the software thread, and I see different lights on the trinket when i press Power + Vol. up, however, regardless of what combo i use, the switch turns on to a backlit blank screen. I noticed continuity between pin 0 and ground on the trinket if that means anything. I currently have an SD card inserted with nothing on it, as I just wanted to see if the switch booted first
    Thanks
    Lloyd.

    EDIT: I'm also no longer using the USB disconnect strap, as it seemed whenever i tried that the switch just wouldn't charge.
     
    Last edited by plasticninjaguy, Aug 13, 2019
  14. mattytrog
    OP

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

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    Sounds like your Vol+ is grounded. Check the soldering to the resistor for the Vol+ strap
     
  15. plasticninjaguy

    plasticninjaguy Newbie

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    Aug 7, 2019
    Australia
    i used the alternative strap found on the pcb with the vol+ button on it.
    thanks

    EDIT: can a grounded VOL+ alone cause a switch to fail to start? Also, the LED sequence on the chip, when I press power + vol up, is different from when I just hit power alone.
     
    Last edited by plasticninjaguy, Aug 13, 2019
  16. plasticninjaguy

    plasticninjaguy Newbie

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    Aug 7, 2019
    Australia
    UPDATE:
    Ok so it seems you were right, that was what was causing the primary issue. However, now if I try to normal boot, the switch screen lights with a bright backlight, then very soon after goes dim, however if i try to do a CFW boot, then the screen comes up with the bright backlight and stays like that. I think I had this issue before when the chip wasn't installed, it would flash then go dimmer and reconnecting the ZIF connector between the game card reader and the NAND module fixed it, no same luck this time. Any suggestions? (also, I'm not sure if theres something I haven't done that I sould've, I havent put Atmosphere or Reinx on the SD card, nor have I manually downloaded Hetake, only what came in the UF2 files. Just saying cause I'm not sure if that could be part of the issue.
    With many thanks
    Lloyd

    EDIT: well **** (idk if i can swear here lol), I thought this might be the case, i tapped the screen a few times after a normal boot after noticing the screen going bright and dark after a power button press and realised i was hearing the clicking sound from the "press a button 3 times", anyone know how one might troubleshoot the screen connector?

    EDIT EDIT: Ok, it seems something is stuck hard inside of the screen ribbon cable ZIF connector, any suggestions on how to get something out of there? Also, I'm not sure what this clusterin the picture is for, but it seems that the larger components with the greyish band are shorting to ground on both sides, anyone know what these are for?
     

    Attached Files:

    Last edited by plasticninjaguy, Aug 14, 2019 at 7:58 AM
  17. metaljay

    metaljay GBAtemp Fan

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    Jan 10, 2012
    Can you get any clearer photos? Ill tag @mattytrog as im sure he doesn't get notifications anymore
     
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  18. mattytrog
    OP

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

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    Apr 27, 2018
    United Kingdom
    Looks like you have bent pins in the FPC connector to the LCD. You need to replace it.

    I'd send it somewhere to sort out before anything else goes wrong.

    Either me or someone else.

    The FPC needs swapping and the chip needs fitting by people with a little more experience.

    Not knocking your skills, but it would be beneficial for your console if you sent it to someone to sort out for you.
     
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