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It’s not that hard to reverse engineer anything you know about. You know, there is FPGA, there is PCIe, FPGA model is also known. All externals interfaces are a
by lnsru 2y ago
It’s not that hard to reverse engineer anything you know about. You know, there is FPGA, there is PCIe, FPGA model is also known. All externals interfaces are also known. High probability, that the board is not broken.
Imagine obscure motherboard, produced 25-30 years ago. No current colleague has seen it before. Half designed internally, other half circuits licensed. All the ICs met very aggressive thermal glue and their names are gone. The client is to ready to pay anything for the repair. They sent you crate full of broken boards. That’s where real reverse engineering starts.
- aebtebeten 2y agoreal reverse engineering: https://www.smbc-comics.com/comics/1717609925-20240605.png https://www.smbc-comics.com/comics/1717609925-20240605.png
- gsf_emergency 2y agoForsooth! the "reverse" in https://en.wikipedia.org/wiki/Reverse_mathematics https://en.wikipedia.org/wiki/Reverse_mathematics Has the same semantic value, that one may thus observe "Sufficiently advanced mathematics is indistinguishable from engineering" -not ACC [I'm distraught that WSmith didn't draw the symbol for "Eigen... F*ck you"] https://youtu.be/LUuogMZ0eP8 https://youtu.be/LUuogMZ0eP8 (Healthy Imbecilic Artificial Divinity (メイ))
- 082349872349872 2y ago「 強い、 強い、 だめ、 だめ！」 The more interesting parts of maths lie where one can reach (apparently) strong results from (apparently) weak premises: yield to the desire to start with too strong of an antecedent, and your poor technique kills your own sword/[proper frame hom into 2]: ex falso quodlibet. (look into your sword, Y. Gradstudent Sagiri: have you detached that head clause by cutting into a principal prime ideal and a completely prime filter?) see also https://news.ycombinator.com/item?id=42375498 https://news.ycombinator.com/item?id=42375498
- mikewarot 2y agoOr imagine a Drake R8A receiver, described as "guaranteed NOT to work" that a friend picked up. It can be tricked into working, but it gives a "PWRLOS" display most of the time, and there is no discernable cause. Thanks to the obscure NEC uPD78213 cpu actually being available and documented, and having no internal rom... it's time to write a disassembler[1] (or later find out that MAME has one[2] thats pretty good), look at all the schematics, and figure out how the firmware works. *Still working on the disassembler, because I can eventually make mine interactive, add labels, comments, etc. [1] https://github.com/mikewarot/Res78213 https://github.com/mikewarot/Res78213 [2] https://docs.mamedev.org/debugger/memory.html#debugger-command-dasm https://docs.mamedev.org/debugger/memory.html#debugger-comma...
- lnsru 2y agoOne must love Drake R8A receiver! I would say, that having no internal ROM is an advantage in this situation.
- jandrese 2y ago"No internal ROM" might mean that it relies on a bunch of custom PLA chips which would not be an improvement. With a ROM there is at least a chance you can dump it and run a disassembler on the contents to figure out what it is trying to do.
- lnsru 2y agoLooks like there is regular EPROM in this case. Nothing too ugly. Except very old microprocessor.
- mikewarot 2y agoNope, I've got complete schematics, and a dump of the EPROM. It's going to take a while to figure out how the heck why it's hallucinating a power failure (the signals going into the CPU are appropriate).
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- buildbot 2y agoAny idea how much a service like that actually costs? Say I had an old camera, how much would reversed engineering the CCD drive circuit cost?
- lnsru 2y agoWhat’s your expectation from CCD drive circuit? Understand enough and repair it? Make a similar device? Make a micrometer exact clone? In that case with old crap we used X-ray pcb inspection machine. Made enough pictures to recreate all the copper traces on paper. Was enough to understand how it works and repair.