Super Famicom motherboard vs SNES motherboard

Anyone know if the Super Famicom uses the same motherboard as the SNES?
From the images I've seen they look identical.

I'm aware that the SNES went through revisions where they moved the sound module onto the motherboard at some point. So that is the only known factor I'm aware of.

No difference. Even when it came to revisions.

They are identical. The only difference is that a different power plug + back cover is in place. I have a US motherboard in my SFC, you would never know.

Surely at least the RF modulator must be different as Japan uses different TV frequencies?

The RF modulators are separate/external to the console itself. I'm sure this is the case with the SNES vs. SFC since it is with the NES vs. FC; meaning, you can use a NES RF adapter + Famicom + US/NTSC TV just fine. The posts where I debunked that are here and here. As said, I'm sure the situation is the same on the SNES vs. SFC.

On all my old-style SNES consoles, the RF modulator is built in, with an RCA connector on the back that outputs it (just like the NES). The modulator is a separate metal-shielded module inside the NES/SNES The external gray box is just an automatic RF switch.

Thanks for correcting me -- see, I was always under the impression the modulator itself was in the external (grey) box, but what you've described makes a lot more sense.

So I'm incorrect in my above assessment (that the modulator is external to the NES/FC and SNES/SFC), and happy to admit that.

On top of that, there is in fact a difference regarding the built-in RF modulator. On US and PAL consoles, the small switch allows you to select between channels 3 and 4. On Japanese Super Famicoms, you switch between channels 1 and 2.

Yeah, I forgot you'd have to swap out the RF modulator as well to make an SNES board an SFC board. That and the power plug are the only differences.

Given wikipedia:Television channel frequencies and wikipedia:North American cable television frequencies:
Japanese OTA channels 1 and 2 should appear as US CATV channels 95 and 96. US OTA channels 3 and 4 shouldn't be receivable on a Japanese OTA-only set. (I have no idea if Japanese cable television is the same frequencies as US ones. Seems likely, though.)

Actually, you were almost right. The RF modulator is seperate to the motherboard, and attaches to four pins (VCC, Ground, Audio and Video). It doesn't matter to the SNES whether it's attached or not, so if you remove the RF box you could still call the motherboard complete as it will still function 100%. But no, the "rf switch" cable doesn't contain the modulator at all.

That was my take as well. The RF adapter is similar to the power jack and plastic shell (and multi out as well?), in that it adapts the back connection differently depending on the region.