Hardware 256GB EMMC upgrade drives me crazy

FinalFreak

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greetings everyone :D
so i got a problem i bought a emmc replacement board and one 256gb emmc chip with soldering balls already attached (part nr. KLMEG8UCTA-B041)
because i am a big dummy i soldered the emmc chip to the board with a temp of about 360°c right after i was done i noticed the temp on the hot air station. i dont know why i didnt noticed the temps i guess i was just excited that the parts finally arrived in the mail. the chip and the board still looked good so i let them cool down and put them in my switch. i immediately went to hekate to check the emmc info but it only shows the "failed to init emmc" message. after that i was a bit anxious that i killed the chip or the board so i redid my work but this time with a lower temperature (around 250°C), checked all the pads under the microscope, nothing wrong there, cleaned everything with ipa, renewed the solder on the pads and tried again still nothing in hekate.

so to my question is there a way to determine if the chip is really dead? im pretty sure the chip was in the right spot but if not (you never know i cant see under the chip :P ) could the chip be shorted or is there some kind of current protection or something? the emmc port on the switch still works fine with my og emmc so i guess i screwed up at the hot air station. i really want to confirm that atleast the chip is dead, like point of no return dead, before i order a new one these things aint cheap and take their time to arrive in the mail :'D

thank you for reading this mess , not my native language :wacko:
if needed i can add some photos ^^
 

thesjaakspoiler

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A very GBATemp-ish solution would be to buy a $1 sd card reader and connect the board to the reader with some fine wires.
The emmc can operate in 1 bit mode so with 6 wires you should be able to test it

Many have done it before.

A dedicated emmc card reader is something like $15 on ebay.

I don't know if you are a student but universities also do have a lot of free equipment.
And my experience that seniors are usually also into this kind of stuff.
 
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Boydy86

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I wouldn't go by set temps and durations. Every station is different. Practice lots on the EMMC that came with the board. Pretty sure the hot air temp on my station was around 350 and done the job fine.
 

evil_santa

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@FinalFreak
Die you measure the distance from the board to the chip from the old one?

I can give you the measurements tomorrow, did you use an odin-emmc board or a hac-emmc board?
if nothing works send it to me I can assemble it for you.
Or buy them directly from me over my discord.
https://discord.gg/fq6658a9HD

here is a picture with the correct measurements for hac and odin emmc. use a digital caliper to check that you've soldered it correctly.
 

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FinalFreak

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okay where do i start sorry i couldn't answer earlier was on vacation and didn't had internet access ... anyways

so if we take the sketch from @evil_santa
there is a super tiny ceramic cap at the bottom of the emmc chip, i checked
the resistence and it just goes through the roof so i figured maybe the chip survived and just that cap is dead. after that i ordered a new emmc module and that thing arrived today in the mail.
i hope i have some time tomorrow to try it again.

and to answer a few question :)

@thesjaakspoiler oh damn thats neat! exactly my type of solution to a problem + i have a few sd card reader lying around :D
i guess i didnt have to put the board into the switch everytime to see if the emmc swap was successfull. thank you for the tip!

@Boydy86 thats a little relieving to hear, i really hope the chip is still fine and yes before i try again i will practice a little more. ^^

@evil_santa no i didnt measure the distance between board and chip. i was super hyped up at the time the board and the chip arrived in the mail i probably should've measured it.
i did use a hac board and i wouldn't say no to a few measurements if they are still available :P
and thank you for the offer but now its a thing between the board and me, cant let anyone finish what i started you know :D but thank you nonetheless <3

Edit: update time! so i practiced a lot yesterday and today, i soldered both donor emmc's (the left over 32gb ones) on and off the new board and pretty much every try except the first was successfull and hekate recognized the chips. i'm pretty confident now that i can do this chip swap
then like an hour ago i soldered the 256gb chip on the board and checked hekate it still fails ... so guess here ends the journey for now chip is dead i will probably order a new chip when the prices on aliexpress are a bit lower.
if somebody find this in the future i just got one advice for you.
be a smart boy and check your temp on your hot air station before you start working with it
 
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gokuz

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be a smart boy and check your temp on your hot air station before you start working with it
I'm 100% sure you destroyed the chip by using a cheap rework station. Those aliexpress generic rework station with fan inside the nozzle will take too long that it will destroy the chip.

Example, I use MAX 450C to solder nand and it only takes 10-20 SECONDS.

Those generic aliexpress hot air station will take 1-2 MINUTES for the solder to flow.


Be a smarter boy next time and use a reliable rework station. Facepalm.
 
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HollowGrams

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I'm 100% sure you destroyed the chip by using a cheap rework station. Those aliexpress generic rework station with fan inside the nozzle will take too long that it will destroy the chip.

Example, I use MAX 450C to solder nand and it only takes 10-20 SECONDS.

Those generic aliexpress hot air station will take 1-2 MINUTES for the solder to flow.


Be a smarter boy next time and use a reliable rework station. Facepalm.

32GB modules don't require much heat for lift / re-attatch. I've killed a few testing temps / distances myself. If you need some spare modules to see if the 32GB package still works PM me.
 

gokuz

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32GB modules don't require much heat for lift / re-attatch. I've killed a few testing temps / distances myself. If you need some spare modules to see if the 32GB package still works PM me.
Most people don't get hot rework stations matter for micro soldering.

Its mostly about the duration you put heat into it. If you killed it, most likely you're using a generic hot air station as it won't melt as fast and you will put it longer.

If you're using a reputable hot air station 450C can melt it (32GB modules) in 10-20seconds easy. Using those generic ones will take 1 minute or longer which will kill it.
 
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HollowGrams

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Most people don't get hot rework stations matter for micro soldering.

Its mostly about the duration you put heat into it. If you killed it, most likely you're using a generic hot air station as it won't melt as fast and you will put it longer.

If you're using a reputable hot air station 450C can melt it (32GB modules) in 10-20seconds easy. Using those generic ones will take 1 minute or longer which will kill it.

This is true - My quick lifts it like butta. The cheapy killt shit.
 

evil_santa

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Edit: update time! so i practiced a lot yesterday and today, i soldered both donor emmc's (the left over 32gb ones) on and off the new board and pretty much every try except the first was successfull and hekate recognized the chips. i'm pretty confident now that i can do this chip swap
then like an hour ago i soldered the 256gb chip on the board and checked hekate it still fails ... so guess here ends the journey for now chip is dead i will probably order a new chip when the prices on aliexpress are a bit lower.
if somebody find this in the future i just got one advice for you.
be a smart boy and check your temp on your hot air station before you start working with it
hmm that's very annoying. do you want to send me the emmc maybe you will still go? if i remember correctly you come from germany? If it works, I'll send it back to you.
 
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