Give it to me 'cause I only use headphones?
Seriously though, sounds like a blown final audio amplifier stage to me. I don't know anything about the FT-1000D but I bet if you find a schematic and work backwards from the speaker, the first (or maybe 2nd or 3rd) active device you find has given up the ghost..
If I had to guess, you're gonna want one of these:http://www.mouser.com/Search/Refine.aspx?Keyword=511-TDA2003V
I got the manual from here:http://www.dxspot.com/transceivers/yaesu/ft-1000d.html
No idea if it's even the right manual or not ... but if you trust it ;-)
Here's some info that suggests maybe someone has had a problem with damaged regulators (the transistors near the chip) taking out the audio chip:http://lists.contesting.com/pipermail/yaesu/2002-December/004128.html
You're looking for Q3022 and associated components in the schematic I think.
Could be something else, but that's where I'd start poking around.