The IC you’ve removed is the CPU regulator, Android won’t boot without CPU so unfortunately in this case you needlessly removed a perfectly fine IC For future reference, if you don’t know what your removing or the purpose of a particular IC then you don’t have any business touching/reworking it
How are you reballing this IC? you’ll need stencils and solder paste, you can’t just tin the IC/board with your iron and hope for the best. the rest of the board is still ok
Ok, the reason I brought it up is because the chip you’ve put on is wonky, this can be down to what I mentioned above but also as a result of not properly wicking the pads prior to IC install/reflow or because of overly agressive wicking which results in over exposure of the pads which can skew the IC during reflow… if you can confirm?
Where did you get the IC from? a legit EU/US supplier or from China?
My best guess is this is an install and or chip issue as that’s when the symptoms changed.
I don’t think this is anything to be concerned about, I’d guess it’s just denoting a version/revision of the IC, if it’s producing your primary rails then it’s likely fine
I thought so, the chips reball looks poor and I can see minor damage on the chip itself (likely indicating these are recycled and reballed IC’s… which is pretty common)
Well there is, sorry the chip is/was wonky which can be due to any of the reasons I mentioned earlier, while in some cases this won’t cause issues it does in this case throw in an element of doubt.
Not really, you can measure the resistance to ground on the VIN (SYS) and also the resistance to ground on the primary output CPU rail (inductor/s) and see how it compares to a known good. The other way (which you can’t do) is checking the voltage on the CPU rail output while booting L4T Ubuntu/Android.
It might also be your unlucky, and the SoC was the original issue (maybe joint related or just age), your rework nearby could have just changed something (assuming your IC and install/s have been fine) or just too much heat in the area which seems somewhat likely given I can see quite a bit of abuse heat wise to the caps and speaker connecter etc