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Laser-ing the IC markings off on a budget.
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beanflying:
I don't think even the OP is under the illusion of what removing the markings from chips will and wont do. Anyone determined with the skills and time can figure there way through most circuits. Software protection makes a lot of sense by physical means but that is only a hurdle not a complete solution.

Even potting can be defeated, the first time I did this was on a depth sounder as a 16 year old where the potting (more of a thick 5-6mm coating) was I suspect part waterproofing and part design protection. Messy ugly but got in did the repair on a blown transistor.

Sanding markings off for 1-10 yep sure if you must but 100-1000 not likely and if you use rotary sanding gear you are at risk of static buildup and damage so just don't. A Laser makes far more sense and if a company goes down that path with the right one then they have plenty of other use cases.

Taking the markings off a jellybean 8 pin device is just too :wtf:
james_s:
Potting is easily defeated in many cases. I repaired a bunch of potted HeNe laser power supplies and even completely de-potted a couple of them by heating the epoxy until it softened and then scraping it off. I found I could also peel the layer off the bottom, desolder all the parts, then heat it up and peel the PCB off of the potted brick containing all the components and then heat that up and break it apart to get most of the parts out. The potting on those is done mostly for insulating reasons but the fact that they are all potted motivated me to reverse engineer several. I repaired a few of them too just by identifying the bad part from the bottom and then milling it out with an endmill and inserting a new part down in the hole.
mnementh:
Mill the part smooth then laser-etch a in-house stock number which is "accidentally" similar to a completely unrelated part in a similar package. >:D

You know, like some devices I've seen that "accidentally" have a positive DC rail on a black wire, just for grins.  ;)

mnem
"...I'm goin' straight to Hell,
just like my momma said.
I'm goin' straight to Hell..."

https://youtu.be/CSvf6FsSnjg
SilverSolder:

--- Quote from: james_s on March 24, 2021, 01:09:15 am ---Potting is easily defeated in many cases. I repaired a bunch of potted HeNe laser power supplies and even completely de-potted a couple of them by heating the epoxy until it softened and then scraping it off. I found I could also peel the layer off the bottom, desolder all the parts, then heat it up and peel the PCB off of the potted brick containing all the components and then heat that up and break it apart to get most of the parts out. The potting on those is done mostly for insulating reasons but the fact that they are all potted motivated me to reverse engineer several. I repaired a few of them too just by identifying the bad part from the bottom and then milling it out with an endmill and inserting a new part down in the hole.

--- End quote ---

LOL keyhole surgery!  :D
james_s:

--- Quote from: mnementh on March 24, 2021, 03:45:47 am ---Mill the part smooth then laser-etch a in-house stock number which is "accidentally" similar to a completely unrelated part in a similar package. >:D

--- End quote ---

Some early arcade games from the pre-microprocessor era did that. I saw a board that had a standard 74xx number on a part that was obviously a bipolar PROM. Just looking at the schematic you could see it was clearly the sprite ROM.
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