A tech just worked on my HL-T6189S set to fix the blue halo problem, improve focus, and eliminate a loud buzzing sound. The blue halo is now fixed (the black lens ring fix as discussed was installed) and the focus is improved.
He replaced the mainboard to try and eliminate the buzz, but it did not work. The loud buzz sounds like it is coming from the LED light source. Does anyone know the magic words to tell Samsung customer support to get them to fix the buzz in the LED light source (I assume replacing it)?
Something interesting: the new mainboard has a date of 2007-09-21 with a firmware version of 1019 ("MODULE: T-LAU2AUS0-1019, DATE: 2007-09-21, MICOM: T-DLEDAUS5-3029").