Blinking led?
 

In my ps2 there is a blinking orange led in side it only blinks sometimes though it looks like it might be on the top of the motherboard inside
i have a ver9 with a duo2

Yeah that happens when your PS2 is cold, thats the camp fire light....... no J/K!!!

Thats the network addapter/HDD activity light. With some games even if you dont have a N/A the game sets it off for some reason. Why? I dont know.

it looks like a fire kinda, at first i thought it was like a hd activity led

i only get that when i go online !!!!! thought it was strange to start with but its one of those things now lol :p

Same here. Mine makes a little whiny sound as well. I figure it is just the drive humming a little. It stops after a few mins of play though. I have only noticed this a couple of times though. THPS4 does this sometimes. :( I hope my drive isnt going to quit on me. That would bite.