Brother MFC-9320CW No Ethernet Link Repair

After the lightning strike on our mains transformer one of the printers (Brother MFC-9320CW) lost Ethernet link.

Upon further troubleshooting I concluded that the PHY chip gave up the ghost.
The chip in question is ASIX AX88796BLF. It appears from the board it has absolutely no input protection what so ever, hence it gave up the ghost.
A bit of warning: the AX88796BLF comes in QFP64 7mm x 7mm package with a microscopic 0.4mm pin pitch. I would not recommend this repair without hot air.

Luckily the chip was not too obscure and I could get one from ebay for around $10 (although due to COVID19 one of the sellers cancelled the order) .

Here it is:

ASIX AX88796BLF (new)

Disassembling printer is relatively easy: two screws, a bit of plastic bending , couple of clips and the side panel where the main board is, is out.

screw no 1
screw no 2
couple of clips
catches on the bottom
some bending
main board shield is exposed
main board
main board top side
main board bottom side (where the PHY chip is)

The hard part: the package is QFP64, the pin pitch is insanely small, I do not own a good hot air station (just a shitty hand held hot air gun).

AX88796BLF before removal (dead)

The chip came off easily enough, although it picked up two capacitors and resistor (R281, C229 and C230), which was a bummer.

chip removed

New chip was a huge pain in the ass to solder on. To start with the cheap shitty hot air gun gave up the ghost right when I positioned the chip 90%. So the end result had a few shorted pins and minor alignment issues. I had to manually solder the capacitors and the resistor with the soldering iron. That was a mission and a half due to microscopic size of the components (I do not have a microscope either).

After soldering I checked every adjacent pin for shorts and gently realigned pins with the chisel tip for better separation.

New chip is in, no shorts! (eventually)

After 3 or 4 rounds of checking for continuity and gently touching up the pins I was happy with the result. Testing semi-reassembled I got the link/activity lights!

Link UP!

QFP64 with 0.4mm pitch is a bitch.

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