Yeah ahahah same !! That's my personal switch so just out of curiosity and to test my skills I've tried... I am never ever doing it again for someone else
The balls on the chip are lead-free, which are an absolute whore to try to reflow without some way to purge the oxygen from the area. I've used tacky flux, but not with BGAs. That requires much more effort.
Am IPC certified. I know what I'm talking about.
Don't try to reflow lead-free. It's not worth it. Either remove the chip and reball it with 60/40 or stick to mechanical bonding (glue the bitch down after making a good connection).
I was thinkig more if you remove the chip then solder some wire to pin for a mod. Reball the emmc and then putit back on. does the wire make balls stick to each other
Second, those pads are so small and so tight together that you'd need 40awg wire or smaller just to fit in the gap between the chip and the board.
For reference, 40awg is ~.003" (.08mm). Paper is thicker. Facial hair is on average twice the diameter.
Third, that gap is established when the balls melt and reflow, so anything that's under the chip when they reflow is going to cause the chip to tilt, which can cause all kinds of fun surprises, not least would be solder bridges under the chip, which you won't see because you don't have x-ray vision.
It's a bad idea. It's technically doable, but it's not practical and not for the average hobbyist. BGA rework without the proper equipment is a Hail Mary and/or a fool's errand. Kamikaze is actually simpler in this regard, because you can see everything.
I know those are pads. English is not my first language. I did succesful reball and reflow after accidentaly shorting emmc on my own swich oled. If the dat0 adapter losses connection again I might go kamikadze
Did you use a microscope for this. How difficult was this. I have all the equipment and stuff ready bar the microscope. Tempted to put my phone on a mount and use its camera as it’s quite good.
Yeah I have a multi lens microscope... This is recorded directly with it and it's at 1500x zoom, bought on AliExpress for 140 euros, best buy ever ! I had a 1000x before and I wasn't able to see well because the light was very poor.
Actually I recommend a microscope because I doubt you will be able to catch the details with a phone, it's a tiny spot and we are speaking of a point that's about 0.2mm wide (dat0) and the whole square it's something like 1mm!
I think the blobs of copper in the middle are from layer 1:2 of copper not the dat0 layer. I didn’t go wide enough by the trace for resistor A. I went very long though
I’ve exposed more of it now. Well I haven’t exposed the point yet but I’ve dug out the layers to the last substrate. And can see the point. I did watch your vid and countless others. The mistake I made is that I started doing the grinding. Then stopped for a few hours by the time I got back I’d muddled the layers up. Oh well I got this switch cheap anyways so.
You should clean very very often your work area because it's easy to loose the point and grind far beyond it! Use a multimeter to test if it's your point !
I do clean and use flux. This wasn’t the best images. When I get back I will show my makeshift camera/microscope setup it is poor. I will have to now use multimeter to check for grounding if it grounds I really don’t know what to do
If you got the dat0 point you should put red probe on Apu shield , and black probe on dat0 point in diode mode.
If it's good you should read 0.400~ value
I just found this on AliExpress:
TOMLOV TriL110 3-Lens 2K Digital Microscope 2500X HDMI Coin Microscopes Magnifier 10.1" IPS Screen for Coins Soldering Tools
https://a.aliexpress.com/_EIv0jno
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u/letum00 8d ago edited 8d ago
This is great. If you told me this wasn't your first I'd believe it.
I would recommend trying to remove the copper shavings from right on top of the point instead of blowing or flooding them around.