To help the original poster, you won't likely find a repair shop anywhere that will work on machines this old. Uniserver (who posted above) has a mail-order business of replacing capacitors on old logic boards, and does a good job of it. I'm not sure if he does other troubleshooting work too, but I think he does.
If you're interested in learning more on your own, then get yourself a cheap multimeter and a copy of the Dead Mac Scrolls, and go to it. You may not be able to fix it, but you can probably narrow down the problem, at least. You're not going to kill yourself with a shock - just don't touch the high voltage part of the CRT, or discharge it using instructions in the Dead Mac Scrolls, or leave the machine unplugged for a while to let the high voltage bleed off.
Given the symptoms you described, you've got power, but no boot chime or picture on the screen, so it's likely a logic board problem. It's probably worth opening it up to take a look inside at least, and maybe you'll see an obvious problem like a battery that exploded and ate away the logic board with spilled acid.