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reverse engineering: request for chip donations 
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Joined: Thu 13 Aug 2009, 20:39:00

Posts: 33
Post reverse engineering: request for chip donations
Recently, the NES PPU was decapped and delayered, spawning transistor-level analysis efforts (e.g., [1]).

Would anyone be interested in donating CPU and PPU samples to extend this to the SNES?

Thu 01 Nov 2012, 03:53:51

Joined: Fri 10 Apr 2009, 15:00:08

Posts: 13668
Post Re: reverse engineering: request for chip donations
Man, an hour and a half to simulate one frame ...

Who is going to be doing the decapping and scanning? SNES circuitry is going to be a lot more complex than NES circuitry.

The SNES DSP is also the most interesting. It's possible that it has firmware inside of there. Not too likely, but more likely than anything else.

Fri 02 Nov 2012, 03:15:28

Joined: Thu 13 Aug 2009, 20:39:00

Posts: 33
Post Re: reverse engineering: request for chip donations
Greg James will be doing the decapping, and I will be doing the delayering and layer scannings.

Fri 02 Nov 2012, 11:51:02

Joined: Thu 13 Aug 2009, 20:39:00

Posts: 33
Post Re: reverse engineering: request for chip donations
If no one is interested in donating, I can offer what I did for the NES (since I am not based in the US): I would buy some used console(s) on Ebay US, have them shipped to someone in the US volunteering to desolder the chips (and keep the rest), and forward them to the US decapsulation address (I would provide the porto).

Sun 04 Nov 2012, 04:11:59

Joined: Fri 10 Apr 2009, 22:30:48

Posts: 3797
Location: Salem, Oregon
Post Re: reverse engineering: request for chip donations
I'm very interested but broke, I also would like a proper Super Famicom to be used, being the original unit, is there any way I can arrange a Super Famicom to be sent for this honor?

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Sun 04 Nov 2012, 10:20:00
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Joined: Tue 13 Sep 2011, 14:54:16

Posts: 779
Post Re: reverse engineering: request for chip donations
So we could re-produce a replacement for the NES PPU so we can stop harvesting them off Play Choice units for RGB?

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Wed 07 Nov 2012, 14:07:02

Joined: Fri 10 Apr 2009, 22:30:48

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Location: Salem, Oregon
Post Re: reverse engineering: request for chip donations
received 1 Super Nintendo for processing, now I need to get the tools to open it up, and take a refresher on how best to desolder the chips without damaging them. I'll post videos of my work as I go.

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Sun 18 Nov 2012, 05:40:22

Joined: Fri 10 Apr 2009, 15:00:08

Posts: 13668
Post Re: reverse engineering: request for chip donations
The best method I have seen for surface-mount desoldering was to use a heat gun (not a hair dryer), and ideally one with a very tiny spout for the air to come out of.

This is tricky because it can super heat the chip and damage it. Although I had my MAD-1 at 400F before I got it off completely and it works, that's probably a lot less delicate than the PPUs.

If you're removing chips, you're ending the life of that deck anyway. So I might suggest using a really sharp blade or power tool, and cutting around the chip, so he gets about 1-2cm of PCB and all the pins on what you cut out. Leave it to the decapper to desolder it that way.

And an aside, I'm sure everyone in this thread knows this, but just in case: the SNES has two PPUs. One does the color/blending stuff, the other does the BGs. I don't have more info on which does what.

Sun 18 Nov 2012, 07:13:42
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Joined: Tue 13 Sep 2011, 14:54:16

Posts: 779
Post Re: reverse engineering: request for chip donations
...... You dont use a heat gun to remove SMD components. Use a soldering iron with a special canted tip, flux, wick and Chip Quik to keep the solder molton.

You will ruin the part removing it improperly. I have a dead board with good PPUs ill tool up and pull them if youd like but youll have to wait a mo

They demonstrate how easy it is here: https://www.youtube.com/watch?v=FTQqjggeklo

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Sun 18 Nov 2012, 08:15:29

Joined: Fri 10 Apr 2009, 15:00:08

Posts: 13668
Post Re: reverse engineering: request for chip donations
Oh, sorry. I definitely don't know a lot about the field, but I've seen a whole lot of videos using this technique. Ex:

https://www.youtube.com/watch?v=7KgVSoioWSc
https://www.youtube.com/watch?v=AxYhF6Ab2CU

Sun 18 Nov 2012, 08:27:32
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Joined: Tue 13 Sep 2011, 14:54:16

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Post Re: reverse engineering: request for chip donations
No need to be sorry , im between places right now so what ill do is when im tooling for PCE mods ill grab the tip and chip quick and mail whoever is doing the decapping.

I just want to help advance understanding of the console. Its the least i can do. im also curious why the split PPU video appears to be darker than the one chip video.

Early december ill tool up and get the work done.

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Sun 18 Nov 2012, 08:42:58

Joined: Fri 10 Apr 2009, 15:00:08

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Post Re: reverse engineering: request for chip donations
> im also curious why the split PPU video appears to be darker than the one chip video.

Could be any number of reasons. SNES Jr is ultra-bright, so you need resistors on the video output lines.
Could just be one-chip dropped the resistance on the video output.

Sun 18 Nov 2012, 09:09:51
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Post Re: reverse engineering: request for chip donations
HAs anyone decapped the SHVC chips yet?

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Sun 18 Nov 2012, 09:19:57
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Joined: Mon 20 Apr 2009, 08:11:50

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Location: 日本
Post Re: reverse engineering: request for chip donations
Err...which model and why would the Japanese ones be any different?

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Sun 18 Nov 2012, 09:52:08

Joined: Fri 10 Apr 2009, 15:00:08

Posts: 13668
Post Re: reverse engineering: request for chip donations
The Japanese save all the good transistors for their own consoles.

Much the same way as no Japanese cart was made in Mexico :P

This post is sarcasm, although I don't actually know of any MAXI-/MJSC- Japanese boards.

Sun 18 Nov 2012, 09:59:17
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