clements@bbn.com (Bob Clements) (09/03/88)
In article <1087@unccvax.UUCP> dya@unccvax.UUCP (York David Anthony @ W06BF-TV, Concord, NC) writes: > The FCC has (or is imminently about to) >repeal the "turn off the burst during monochrome programs" rule, >because it is a pain in the ass. The reason that killing the burst >is such a pain is ... > >York David Anthony >DataSpan, Inc The bad side of leaving the burst on is that the black and white picture tends to take on various random weak colors that don't belong there. On the other hand, I have a problem with my Sony XBR (and other Sony sets) and WGBH's mono broadcasts. WGBH turns off the burst, but they leave the 3.58 MHz components ON in the vertical interval test signals. (I checked the rules and this is apparently legal.) The XBR color killer thinks it is getting just enough 3.58 to open, but since there is no burst, the local 3.58 oscillator puts out total junk. This results in intense random color snow during the mono broadcasts. I couldn't find any adjustment in the service manual that would help. Further, the same thing happens on Sony VCRs so that you get the color snow in the color-under chroma frequencies on the tape! Sony sure makes wonderful sets and VCRs when given reasonable NTSC sources. But start bending the specs in the source and the Sony stuff hates it. (Most obvious example is severe vertical jitter when the sync pulses aren't really clean, as they aren't out of most cable descramblers.) /Rcc clements@bbn.com