AI Prime Buzzing (not from fan)

[Sick_man]

So I recently just picked up 2 AI Primes for a steal for $25 a piece but for one of them I noticed that whenever I turn the light on, it starts dimming and lighting back up again and buzzing. After about 10 seconds it stops and if the light has been off for a while and turned back on it does this. I also noticed the power adapter to be different on this one so maybe it has something to do with that? The light works fine but the only issue is that it does this for a few seconds whenever it gets turned on. Any idea what is causing this?

 

[lapin]

Does sound like a power issue