Aiwa MD AM-C80 remote malfunction

If I had to hazard a guess I'd say the remote is faulty, Possibly a bad
cable.  Other possibilities include a falty connection inside the player

But first thing I'd check is the remote itself.  To do this there are
three ways

Method 1: Find a friend with another A-C80 and try your remote in his box

Method 2: Same friend, his remote your box  (note, combining 1 and 2 is
kind of like belt and suspenders, but if you do that you totally
eliminate one or the other as the problem beyond any shadow of a doubt

Method 3: Send both to Aiwa factory service and let them figure it out

Note 1:

Try this... First  inspect the plug, If it is a flat circuit board with
traces use a pencil eraser to gently "Erase" any dirt that might be on
them and polish them up nice and shiny.

Then try try plugging it in and unplugging a dozen or so times with the
unit completely power off, I mean remove batteries off, I want it so far
off that you can't even turn it on

Dirty contacts on the remote plug or socket could cause this too,

Hmmm , thanks John.

Further investigation has shown that any headphone plugged into the jack
, with - or without the remote , will cause this malfunction on the player.

Could it be this "dirt" you where referring to causing some sort of a short?

Cheers
Conrad

Not likely, since the only thing the headphone and remote jacks share is
  a neighborhood (they are next door to each other) I'm assuming Aiwa
uses the SONY style where the remote plug is a headphone plug with a
blade next to it, the blade is the remote plug.

This sounds more like a problem with the circuit board inside the
recorder, Possibly a bad solder joint, broken trace or debris on the
board, In any case, I would suggest service for the unit under these
conditions.