Thanks for these vids @JohnnyMeduse! The liquid in the clear plastic bottle is flux, correct? (asking for those who might only use flux paste)
@chaka Yes it is always a good idea to reheat the board, but because the Vesc is a pretty small pcb it wonāt really create stress on other component, also the board heat pretty well there not enough heat dissipation, to give problem with juste the heat gun. @treenutter Yes, this is liquid NO CLEAN FLUX.
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I managed to get the DRV8302 chip off of my VESC last night without too much trouble. I tried using flux paste, 2.5mm solder wick, and a small-tipped iron to clean up the board and it didnāt work very well. I still had bridges left over from the removal of the DRV8302. I also tried to remove it with hot air, but it caused more damage than anything (I melted a part of the jst connector and accidentally displaced one of the small caps).
Iāve got some liquid no-clean flux on the way, with a needle-tipped bottle to apply it accurately. Iāve also ordered some kapton tape (Thanks @chipoi84) to protect things while Iām in there.
I have a 3rd hand tool w magnifying glass, and at 10x and 60x loupes. But those still didnāt seem ideal for magnification. Is there some obvious thing Iām missing here to clearly see whatās going on?
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If I may give you a word of advise, always use a Tips that is larger, like 1.5mm, the larger the tips the more solder it will absorb on the wick, also put a bit a flux on it. Also use the same motion on each pad when you clean it. And the two short you see a normal, they are par of the circuit.
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@JohnnyMeduse thanks Iām always happy to get advice! Iāll try a wider tip while using the solder wick (waiting for the liquid flux).
THANK YOU for confirming that those two shorts are normal; I thought I was going crazy trying to remove them.
The strange thing about this DRV error is that once I removed the chip I didnāt see any evidence that the DRV8302 was damaged; no holes, not burnt spots, etc. At first I thought those shorts might have been caused by overheating or bad soldering at the factory.
I have change a few of them, with this king of problem, and never see any mark or damage, it more likely to be a internal failure. The problem seem to happened when you go over 70000 rpm. I have de same kind of problem with MCU who are internally short. That the beauty of electronic it alway a new adventure 
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Here in germany is one company that will swap a DRV for 50ā¬ included a new chip excluded the shipping. A lot of money but if you cannot swap it yourself it is the best way to goā¦
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@JohnnyMeduse @chipoi84 the liquid flux works like a charm! How did I get this far without it? I found that dousing the solder wick with it made a huge difference. I was able to clean off all of the old solder on the board.
Any tips on how to clean up the other residues left on the board?
Another challenge is keeping the chip in place and lined up while I apply the hot air. I donāt want to use too much solder paste, but too little makes the chip slide around like a hockey puck!
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You can put a little bit of Isopropyl Alcohol and brush it, or just brush it without the alcohol (if you donāt have any). I suggest using a wooden Brush (because the are made for this purpose, the one in the picture is from MG Chemical).
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Thanks @JohnnyMeduse! Any tips on lining up the DRV and keeping it in place? I feel like it jumps around on the board and I canāt keep it steady!
If you/'re talking about soldering the chip [edit] with a soldering pencil [/edit] do the following:
Place the chip on the pads aligned as close as you can get. Hold it in place with one finger and using your soldering iron, tack down one pin in one corner. Now pick any other corner, re-align the chip and tack down the pin on that corner.
flux and solder all pins.
DougM
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Thanks @DougM. That sounds like a good strategy! Iāve been trying to line it up evenly and then hit it all with hot air at once, and that hasnāt worked. I almost got there once, and then I accidentally tapped the chip with the hot air gun!
Iāll try tacking down a few pins with my iron first (maybe 4 of them?) and then Iāll use solder paste, flux, and hot air to get the rest.
Hot air is tricky - the airflow has to be low enough not to blow the chip off the pad because the pins you tacked will re-melt. This is a skill I never developed 
Tacking down the 4 corner pins seems like a good strategy.
DougM
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@DougM I think I need to use hot air to get the pad under the DRV to make contact, but of course I have to do that without melting everything else! Kapton tape is helping for sure!
And donāt forget to save the jst socket from the hot air. The plastic is melting quickly.
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@treenutter - Yes, getting the pad underneath soldered correctly is critical. pre-heating the whole board helps with this.
Iāve never tried this but you can get hot air rework nozzles like these
that allow you to localize to a single chip.
DougM
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I use a regular big old heat gun, and it works fine. Just make sure to heat the entire board carefully first, before apply the heat on the drv chip. Also, it would help to use solder wick to clean and make sure the solder pads for the drv chip is even first. If you have one of those soldering helping hand, it would help a lot to keep the entire pcb even, preventing the components from moving around. When I heated my drv, sometimes it would move perfectly into the correct position by itself due to the pull of the solder paste. If not, I would hold the heat gun in one hand, and adjust the chip using a tweezer with the other hand.
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iāve helped replace two dead DRVās now - with a reduction tip on the hot air to focus the hot air just where you want it, and ability to turn the air flow down so you arenāt blowing other components off their pads when they also melt.
Some kapton tape as a barrier definitely can help if you just surround the DRV chip to deflect hot air from the other components.
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I thought it was impossible to remove drv chip without fancy soldering equipmentā¦ BUT after I realized that FOC fued up also my second VESC on mountainboard (which I thought was ok), decided to give myself a try and remove that little fuer. I used: laser thermometer (for controlling temp of pcb during preheating), heat gun (used for preheating board from bottom), gas solder iron (with removed tip, it blows narrow stream of hot air, used for final heating drv chip), flux and obviously tweezers. Here is effect:
Two new DRV8302 chips are on their way, should be here on monday.
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Thx @hexakopter, thatās good advice but Iāve already demolished the jst connector! Iāll have to replace it.
@DougM Iād never seen those before thanks!
@chipoi84 so far Iāve been taping the pcb to a metal surface but a jig would be a lot better. Yes, Iāll be sure to clean the pad before I mount the chip. I think Iāve been skimping with the solder paste.
@sl33py Iāve got kapton tape all over now, itās saved me a few times already!