They've been sharpening the news pegs on NBC's "Weekend" lately, perhaps in preparation for its move into prime time next fall. The last "Weekend" included tasty tidbits on Tongsun Park and tonight's edition, at 11:30 on Channel 4, opens with a look at Rep. Daniel J. Flood (D-Pa.), whose problems with scandal appear to have had no effect on the faith his constituents place in him. Buddha himself could hardly have asked for fealty more stalwart.

The segment with the greatest impact comes later in the program - producer Craig Leake's report on a Butler, Pa., teacher who has devised a terrorizing program of "last chance" education for problem juveniles considered likely dropouts. The curriculum includes paddlings (the camera flinches from showing the actual blows) and a visit to the local morgue for an autopsy.

Even a haircut becomes a weapon of oppression; footage of that ritual and others proves both harrowing and heartbreaking. Except for a cynical if justifiable afterword by the producer, Lloyd Dobyns' narration remains minimal and unobstrusive. The story is told in the faces of the kids.

Other segments, including one on a Washington on nightclub for Vietnamese, are only fitfully successful and sometimes marred by talkiness. But a backbone of compassionate outrage keeps the program's attitude distinctive and decidedly antidotal to that of most TV news shows.

"Weekend" is still a gentleman in Palookaville.