Power Supply Mystery
I didnt really understand the concept of current:-
see,how did you measure the current.Was it just like as you measure the voltage,by putting the meter in the current range and holding the probes across those two wires?
if so,thats not absolutely the current.As you said you are new to electronics,it can be pardoned
I can teach you some basics about the current:
you cant measure the current unless it is loaded.
it means,you need to connect some load,any other device,to the output of that said adaptor,to find some current is drawn or not.And that too,the meter should be in series in the ckt.Here as you said,the one you said can supply only 400mA.So never you will be able to read 8A in your meter.
Now how to go with it:-
just plug in that adaptor i/p to the specified 110/120 AC mains.Dont worry,Nothn will explode.If there was no blasting happnd,just take th emeter,see the voltage across those two o/p cables.If it shows 30,ii is fine.
Or else,the stuff is not working.