Discovering a Raspberry Pi 4 in inventory remains to be a problem, however issues are beginning to lookup. However what should you want a Raspberry Pi 4 8GB, now? May you flip a 1GB mannequin into an 8GB? Effectively that’s what YouTuber MadEDoctor has finished with a substitute RAM chip and plenty of soldering.
Earlier than we get to the meat of the story, a phrase of warning. You may have most likely guessed already that it will invalidate your guarantee. Additionally, you will want the talents and the finest soldering stations to even try it. That is an excessive means to pay money for an 8GB Raspberry Pi 4, but we appear compelled to present it a strive.
| Row 0 – Cell 0 | Chip Code | Alternate Chip Code | Worth |
| 1GB | SEC928 | Row 1 – Cell 2 | Row 1 – Cell 3 |
| 2GB | Micron D9WHZ | SEC940 | $23 |
| 4GB | Micron D9WHV | Row 3 – Cell 2 | $41 |
| 8GB | Micron D9ZCL | Row 4 – Cell 2 | $21 |
MadEDoctor begins out with a Raspberry Pi 4 1GB, which is proven to be working to spec. Then the enjoyable begins. Desoldering the RAM chip requires a sizzling air rework station and plenty of flux. Utilizing loads of Kapton tape to guard the encircling chips and plastic elements, the 1GB RAM chip is first heated as much as 250 levels Celsius utilizing the recent air rework station. The air velocity is ready to 60% to make sure that the warmth permeates into the underlying board. With the board warmed up the warmth is turned as much as 400 C, the temperature required to desolder the lead-free solder utilized in fashionable board manufacturing. The RAM chip is held in place utilizing a BGA (Ball Grid Array) and so the warmth must loosen each solder ball earlier than the chip will yield. This will take a while, and MadEDoctor always touches the chip to examine whether it is unfastened.
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With the RAM chip eliminated, MadEDoctor floods the uncovered pads with extra flux after which makes use of some lead primarily based solder to tin the pads. Utilizing lead solder will make the clear up a bit simpler because it typically has a decrease melting level. Out comes the soldering iron and a few desoldering wick (copper braid) is used to frivolously clear the pads. By no means urgent arduous sufficient to wreck the board. We guarantee you that you do not need to harm a pad at this degree of magnification. A fast wipe with some isopropyl alcohol and a Q-tip reveals the gleaming array of pads ready for the brand new chip.
Making use of the brand new 8GB RAM chip to the board is an analogous course of to eradicating the 1GB chip. The 8GB RAM chip already has solder balls for the BGA. Flux is utilized to the uncovered pads on the Pi and the RAM chip is positioned on prime of the pads, matching the unique orientation. MadEDoctor elected to exchange the lead-free solder balls with lead for his or her chip, and so the recent air is turned as much as 350 C at 40% velocity. For lead-free we would wish to hit 400 C and 60% air velocity. MadEDoctor explains the right way to know when the chip is seated appropriately. The overall steerage is to take your time, and preserve checking the chip by tapping to see the way it strikes.
With the soldering finished, MadEDoctor leaves the board to chill, with only a light air circulate from their fume extractor. The Pi wants to chill slowly, making certain that each connection within the BGA is appropriately made. A nasty solder joint within the heart of the chip could be a nightmare to diagnose.
With the operation a hit, MedEDoctor runs a couple of rounds of memtester to make sure that the 8GB chip is working to spec. Positive, that is an excessive venture, however the abilities to do that aren’t past many electronics hobbyists.