Ballast Question

[ALang]

Hi all.
I had a Coralife Aqualight ballast die on me. MH 250W DE.
So I ordered another one. Couldn't find exact brand replacement, so substituted with a Vertex e-ballast, 250W.
It came, I plugged everything in...**sizzle**, then *pop*, and little tendrils of black smoke came out of the light fixture's vent.
I haven't taken the fixture down to take a look at it (waiting for some muscles to help), but based on these findings, is my MH socket toast?? Can it be replaced? (As I have found parts avail online). Why did it burnt out?? Was there certain sequence that I should have done to plug it in??
Thanks for the help.
Lenny.