For the TL;DR version, skip to the bottom...
Well, it's been a long miserable winter with very little to look forward to.
Spring is finally here, and I decided to ring it in properly with one of my favorite outdoor activities: QRP on the patio. The batteries on my Yaesu FT-817 had gone completely dead over the winter, so I charged them up for 8 hours and to the patio I went.
With everything setup, I was eager to call CQ. Except... I was noticing an output of only about 100mW. After double-checking my connections and settings, I retreated to the garage to investigate the problem. After a few minutes of Googling, I had my answer. Apparently there's a bug with the 817 that if the battery is allowed to go below a certain charge level, the unit does something that destroys the final mosfets. Sure enough... that seemed to be exactly what I had.
I'm well aware of the dangers to the 817 finals by over driving the TX, overheating, bad antenna match, and etc, so I've always been cautious with those issues. Absolutely ridiculous.
So basically it seems that if you abuse the finals, they may blow. If you don't use it at all, it may blow. Fortunately I was able to find a buyer for it, so I'll apply some of the proceeds from the sale to building a new rig from scratch. Ah well... I guess that's what I truly enjoy doing anyway.
PS Yaesu - I'll happily accept a replacement unit. Thanks
TL;DR;
Yaesu FT-817 finals died from the battery going completely dead. It's apparently a known issue.
