Hi and welcome to Just Answer. My name is XXXXX XXXXX have been repairing TV's Professionally for over 7+ years and currently own a Shop in FL.
The white dots are coming from stuck mirrors that should be Oscillating on the DMD Chip. The DMD Chips contains millions of these little mirrors and each one is responsible for creating a colored pixel. You combine them and they create a picture. When they begin to go bad though, they stop creating a colored pixel and stay in the on position which creates a constant white pixel "Dot". Usually when one goes, a lot more follow in a short period of time. This chip usually costs about $200 and must be done by someone who is trained in DLP Projector Repairs. In total, you can expect the Repair to cost about $350-$400. Hope this helps.
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