Mesa 7i92 repair after wrong polarity

Hi,
This is not a question, i just want to show you how i fixed my broken 7i92. I hope this is the right place to post it.
If you're as dumb as me and wire a 12V connection with wrong polarity, your 7i92 will break.
Obviously.
I couldn't get any signals in or out of my 7i92.

I was able to fix it. Heres how:
- check if your Diode CR5 works (red square in the picture, desolder it, test with multimeter) - mine worked
- check if your FPGA chip still gets signals (halshow all your GPIOs and apply 3,3V from the Board to the pins of the "5V Tol" pins, red lines in the picture) - my 7i92 still got Signals. This means your Bus switch is broken
- desolder the "5V Tol" chips: desoldering TSSOP
- clean the solder pads
- solder new FST16211MTD Bus switches on the board, a lot flux helps a lot: soldering TSSOP
- clean everything up
- test it
- mine works again like a charm

This also helps if you connect something to your board without a GND connection. I had some broken pins due to this and the new chips fixed that problem. My broken pins thread
I got my chips from china, because i didnt wanted to spend 28€ on shipping to germany by mouser. cheap china chips

Oh, heres a pic of the newly soldered chips. You realy have to clean up the flux as you can see

Soooo, i was dumb again and didnt remove the powersupply while changing some cables. I had to solder in new chips a second time. Luckily the card is working again.

Did you solder it classic or did you use hot air? Just asking, because there is little space for soldering and I also have a mesa card waiting for a new chip... and I'm not a professional in soldering...

Ralfh wrote:

...
- desolder the "5V Tol" chips: desoldering TSSOP
. ..

I used my biggest solderingtip with a lot of flux and solder on the highest temp-setting (450°C ? i think). With the limited space you might want to remove the tiny SMD-parts before they get lost in waves of hot solder. If you are scared to damage the plastic-clips of the DB-ports or other parts, you could tape a piece of aluminium to it. 
Oh, and take your time. It took about 2-3 Minutes before the Chips came loose. Dont use any force to pry off chips, that will damage the pads underneath. Everything will get hot as hell - but it already is cooked, so no worries

Rather than cranking up the iron temp, slowly preheat the board up to around 100C using a electric fri-pan. This will save putting excess heat into the PCB pads.