Peter, can you use the headphone jack? (don't know what sort of plug it takes, but it might take the same size as an external set of PC speakers) - at least worth a look. At the very least, see if headphones work.
I'm puzzled as to the connection between the RAM and the speaker - that seems very odd to me. Why removing the RAM would make the speaker work is not obvious. Only thing I can think of is that there is a bad solder joint that is affected when the RAM is in the slot. When you removed the RAM, things improved, but eventually the joint gave way entirely. BTW - when you say the RAM went "bad" what exactly do you mean? Did it still show up in the ASP, but simply cause problems with the speaker? Or did it cause other problems or not show up? RAM doesn't very often "go bad" - usually it's bad from the start. Have you tried it in another computer to see if it works elsewhere? And if it doesn't work, where did you get it and was there a lifetime warranty on it? Most RAM has a lifetime warranty, if purchased from a reputable dealer.
If headphones or an external speaker in the headphone jack works, then I would guess that it isn't the amp, but rather something a little simpler, like a bad solder joint/detached speaker wire. I don't think you'd want to spend $410 on a repair - but if the speaker can be fixed for $95, then it is probably worth it. Too bad you can't just pop it over here...it's the sort of thing my husband is pretty good at fixing!