sega master system

i've got a sega master system sitting her in front of me, and it's not working. it's not the ac adaptor, i've tested that on another one, and it isn't the power switch, because i bypassed it, and it's still not working. also, in case you're wondering, there are no obviously scorched parts anywhere. grin.

so now i'm thinking it's a blown resistor or something along those lines. anybody got any idea what parts are most likely to be the problem?

thanks in advance, if anybody can actually answer this?
looks at SMS2 mobo...

hmm, my best guess is that voltage converter on the side (the three-legged square black thing screwed to the silver) as it converts the 10v current to 5v for use by the CPU, iirc. Moreover, capacitors C41, C42 and C43 seem to be connected to it, you might try them as well. Electrolytic caps are known to dry out after several years.