I have a set of Altec Lansing Speakers ADA215 (DELL)-- need power adapter
information. Speaker has 12V, 0.5A, but doesn't state if center pin is Positive (+)
or Negative (-). Thanks

I have a pair of cheap Altec Lansing speakers that came with a Dell system. Not sure what model number they are. But the speaker has a little diagram in the plastic next to the AC adapter input, and it shows the center pin as positive. AC adapter's output is 12V, 500 mA.

Hope that helps.

No Marking on my speakers, It does state to use power supply "Leader Electronics, type
41120050-C5 for CE only.