Hi,
I was looking for some advice from someone having more experience than me. I bought a broken switch showing blue screen when plugging the usbc charger. I checked for shorts and found nothing, then I tried to put pressure on the left side of the cpu and the console booted succsesfully with no issue. So I decided to try to reflow the cpu. The first try was not sucsesfull, I was having the same symptomps and pushing on cpu resulted in a full boot so I tried to reflow a second time. Now the switch has no screen and when plugging the charger it draws 0.48 Amp and the cpu get hot. Do you have any advice to give me? How can I measure if I deep fried the APU? I’m uploading a photo of the switch before reflow and one of the APU after reflow. Ty for your time
When you say the apu now gets hot, how hot? you likely got some bridges under the apu if you nudged it.
You also may have cooked the apu after two attempts and the resin does indeed appear more brown.
Your best bet at this point is completely remove the apu, check for torn pads and fix any you find, reball the apu and hope for the best
I never bother reflowing apus on switches, i always do a reball when I know it is the apu causing the bluescreen
Apu is getting pretty hot when plugging charger, i definetly think I got some solder balls bridged. I just recieved the stencil and 0.2 mm balls. Do you have any advice to reball it? Is it possible to do it without buying the Apu holder?
0.2mm balls are too small. 0.35mm are what you want afair
You need the correct jig to use to hold the SoC and stencil. You need to be careful during removal, reball, and reinstall / reflow otherwise you can kill it. Search the forum as I’ve covered the jig and best practices for reball etc a fair few times
In regards to reballing by hand… imo it’s not worth the time when you can get the jig and stencil for < $40 but you might find it therapeutic I guess
Also worth mentioning, the die may already be toast, so even if good reball is done, it may not help. Heat could potentially being caused by this outside of solder bridges. Worth checking rails directly on SoC caps after removal to rule out and save time going to the effort of reballing if so.
Thank you for your advice, I’ve read quite all of your post because they are always really precise and helpful. I will search again for the correct jig because I would love if the jig could also be used to hold different chip (for example emmc/ram chip and things like that) otherwise 40€ are a bit to much to me based on the fact I do that as a hobby.
May I check the cap on the APU to figure out if it may be already cooked? I checked for the cap behind the Apu on the other side of the board and some of them are reading as 0 Ohms, but I don’t think this may be a proof which can lead to a shorted APU or shorted soldering after reflow. Indeed the cap near the m92 which is connected to the APU doesn’t result as shorted. At this point I am definitely going to remove the APU, but before buying the jig I would prefer to know if it is possible the APU isn’t dead.
If I remove the APU and the rails are not shorted or linked together, I guess this is a clear sign that the APU is dead, right?
If the APU is dead, I have a donor board which had water damage near the audio chip/Max chip, so is it possible to remove the APU, reball it and put on the board with the dead APU if I also swap the Emmc chip?
yeah, the stencils are pretty standard, 80x80 / 90x90 with the four holes, provided you can find the stencil for whatever you looking to reball then you can use the jig for pretty much whatever. also pretty sure you can get this jig for less, think i paid something like 26 gbp delivered a few years ago.
Not the SoC status diirectly while it’s still on the board, only when removed. These caps correlate with rails found on the board and there is better locations to check these “primary rails” (key search term) elsewhere on the board
It’s worth checking you primary rails resistance to ground and noting the readings. After, when the SoC is removed do the same and take those reading again on the board and if any were short prior ensure they’ve now cleared. After then do the same on the caps of the now removed SoC and note the readings, if any are short / suspicious / low then lets you know if the SoC is toast.
Yeah you can do that, though sometimes the cause for the SoC joint issues on your current patient are caused by board warp, so you may find if thats the case that the issue is inherited. If it were me I’d be rresolving that boards issues independent, you wanna avoid reworking SoC wherever possible.
Actually I searched on the forum and I found your post advising for two different jig, the cheaper one is 40 euros delivered.
Ok, thank you for the advice!
Yeah the original problem was a blue screen casued by the board warp, I tried to apply pressure on the top right corner of the APU and the switch was booting fine, so I was suspecting a torn pad/ball and I was hoping a reflow was enough to fix it because I didn’t have the stencil and reball jig. So I’ also suspecting (and hoping) the problem now is that the torn pad is making a wrong contact somewhere, in fact the cpu is getting hot on the top right corner where the problem was initially. I was thinking about swapping SoC on the blue screen switch because apart the blue screen problem, the board was working fine
Have a search on Aliexpress / temu / ebay etc yourself for the same jig you’ll be able to find it cheaper I’m sure, the link i posted is old and prices change… also new customers (email) on Aliexpess (and others) get a new user discount so bear that in mind,
