Is my MIDIFighter Pro bricked?

[Uncle Noah]

After years of searching, I was able to get my hands on a MIDIFighter Pro (Beat Masher configuration, board #2804 if anyone is counting). I anxiously plugged it in, and no "LED snake" light show - the only illumination is the LED of the lower-left arcade button. The MIDIFighter Utility doesn't see it at all. I tried holding down the 4 corners while re-plugging to get into bootloader mode - nothing. I tried holding down the rest button while re-plugging - that makes 15/16 button LEDs light up (the one in the lower right stays off) and as soon as I release the reset button, I'm back to just the lower left button's LED. I've gone through the other button combo bootloader procedures, and there's no joy. I know the chances are slim since the world is a solid decade past this unit, but any advice from anyone is greatly appreciated. If you're a tech that understands the working of the Pro, I'm happy to pay shipping and bench fees if you think you can make it work. Thanks folks.

[DJDoubleYou]

Dude no worries it's very likely fixable, how much technical knowledge do you have yourself, and are you on Windows or macOS?

[Uncle Noah]

As far as technical knowledge, I know how to read the polarity of a LED, I can solder OK, I have spent time computing from the command line, and I'm good at following directions I'm on a Mac but with an older version of the OS (10.12) - but I do have another computer with a slightly newer OS (10.13). Thank you for the help!

[DJDoubleYou]

Ah dude this is deff gonna be doable, I have flashed a MF with custom code before and I know their source code is on GH. Can you check if the mac sees it as a USB device? And if so what kind

[Uncle Noah]

Sadly, it looks like the Mac doesn't see it. I can plug in a working MIDIFighter Classic and that shows up on the USB tree, but when the one-light Pro is connected, it's like nothing is there. I'm guessing it's because the Pro isn't completing its startup.

[DJDoubleYou]

If you plug the MF into a charger does it behave exactly the same?

[Uncle Noah]

I had not thought to try that! The result was the same - no "light snake" - just that one LED lit.

[Uncle Noah]

Here's one other thought -- I have a fully functional MIDI Fighter Classic board (standard MFv1). Can I flash the ROM on that so it sees itself as a Pro, and then swap the board into the Pro case and have that work? I already know I'd need to do a little drilling around at least one of the corner mount holes (It's so funny how many crazy little thing you learn about how these things were built when you tear them apart a bunch of times), but other than that it seems like it should work - I have headers soldered to the expansion ports on the MFv1, so the ribbon connector isn't an issue.

[DJDoubleYou]

That would definitely work I'd say but It kinda sounds like it could just be a faulty connection of the USB's D- and D+ signals, maybe you could try to debug it with a multimeter?

[Uncle Noah]

Excellent thought, and I know how to test continuity with my meter! After looking at the schematic, I see that D- makes its way to pin 30, and D+ makes its way to pin 29 on the AT90USB162 chip. However, when I look at the board IRL, I'm a little disoriented, and I'm not sure which is the right pin. Could you give me some direction? I tried to attach a pic of the board, but it doesn't seem to have made it. :/