Duo-R controllers not working

From Al Stremming <xxxxxx@mala.bc.ca>
Date
Hi.  Long time no post.

I picked up a Duo-R at a local thrift store.  It didn't come with 
anything.  Just the console.

It powers up and runs cards.  I don't know if the CD mechanism works, 
because I can't get controllers to work with it.  I popped it apart, 
and had a look at the board.  It all looks ok.  There's no cold solder 
or any visible damage.  I know that on some consoles there's a resistor 
or fusible link which can blow on the controller interface.  I see a 
bunch of little blue components arranged around the controller port 
which are labeled FL901 to FL907.  Can anybody tell me what these are 
(are they fusible links?)  Any suggestions on how to go about 
troubleshooting this one?

Thanks.

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Al Stremming - Network Services Technician
Malaspina University-College, Nanaimo, BC, Canada