CDrom and hard disk together problem

so i've got an mpc4000

it come with hd, no prob
i try to install a CDROM

if i put it alone as master OK (so it works)
if i put in with HD it doesn't appear, no matter if i try diff master/slave jumper settings, invert the cable (so yes blue connection is on motherboard), try a different cable and so on

again if i use both i can only see HD, but if i connect as master only the CDROM i can use it with no problem

am i missing something?

suddenly it works as HD slave and CDROM master, the only attempt i never did

"open and shut case johnson... now sprinkle some crack and lets get out of here"
I mean, its working so I guess its good? I remember I had to change the settings on the jumpers to hook it up to my pc but I really forgot if the HD was in the master or slave setting when i put it back in the mpc but it looked like this I::I

You are talking about internal HD and CD Rom, arent you?

yes

i read manual suggest to use HD as master and CDROM as slave, but i can't in any **** configuration... so to me it's ok even the opposite