There are no secrets, Only information you don't yet have
w00t! the eye got fixed
I wonder what else will work!
The title of this post was chosen to hopefully return at the top of a possible web search.
This is exactly what happened to me today and it took several hours of researching and repair to fix, I hope this post helps someone shorten their time spent and misery when this happens.
Although it is still unclear exactly why this is a somewhat frequent occurrence with 817's, the fact that Yaesu sells their radio with a power cord without a fuse is without doubt a big contributor to many possible reasons.
So before you do anything, do yourself a big favor and either put a fuse in your existing external power cord or get one that is.
On with the fix
What has happened is internally a miniscule 'trace' of the radio's printed circuit board has burned up, right near the power connector.
I found this documented in several yahoo newsgroup postings with instructions and images on how to go about fixing the problem.
Several folks on the list helped me located a burned power trace on the '817. My radio was only working on the internal battery and would not accept power from the external power jack. At first I thought the problem was the switch in the power connector but it turned out to be a burned trace from the power jack. I was unable to find the burned spot with my eyes but with the help listers it was located with an ohmmeter. I tried to put a single strand of copper wire over the repair but could not get it to stay in position. SMT type soldering aids would be helpful. The burned spot was quite narrow only a few hundreths of an inch. The jpg in this folder shows the repaired spot which seems to be working well. I hope this helps you. My repair was made with a Weller soldering station at half power with the 'stock' tip which is really too large. Be careful not to move any of the SMT caps nearby. Do it quickly and with a steady hand and it should work fine.
Sure its a bit daunting to open the rig and stick a hot piece of metal into it, but take a deep breath, relax and it can be over and done with in a matter of minutes, minus all the screws to put the top back on the rig
I hope this was helpful if you landed here in a panic.