I'm seeing a lot of main board problems online. I think they need to either lower the price significantly on the main boards or find out what's causing them to fail. Mine happened after one of the suction fans started to go bad, probably putting an extra load for power. I have had 5 printers in the past 7 years and the only one that lasted was the first two, the 9000 and the 8000s. I printed with them for over 5 years without any problems except heads, which is normal.
My 9100 was bad from the get go, luckily under warranty, and they replaced several parts to get it going the first time out of the box. My 8300 lost the main board after 2 years. I just got an error code on the 9100 that I'm keeping an eye on. Luckily I bought the extended warranty on that one.
the 8400 is flawless so far. (It's only been online for two weeks)
The local contracted repair guys are pretty much just part changers. They are constantly on the phone talking to the experts to find out what the next step is, unless it's something obvious, and they charge $180/hour which adds up fast. The cost to fix my 8300 was just a tad over $2000. If I had know that going in I would have just bought a new printer.
I may start looking at the Epson's from here on out.