No subject

I would start by checking the PSU (as ever). The 4 wire power cable to the 
drive has ground on the 2 middle pins and +5V, +12V on the outside 2 
pins. Check these with a voltmeter.

Then, you've foudn the EPROM. That's a standard 27128 device IIRC. From 
that you can find the data pins on the 40 pin ICs on the board. One is a 
6809 of some flavour, another is the floppy controller (I think a 
1793-type of thing, maybe a 2793, but I think not). If there's another 40 
pin chip, then it's probably a 6821. From the data, and if necessary, 
address, pins on the EPROM you should be able to identify these ICs.

OK, now check to see if the 6809 is getting a clock. And what about 
reset? Is it attempting to access the EPROM? Is there activity on the 
address and data buses? 

That should at least eliminate 'sillies'...

-tony