As a rule, a network -- and its local affiliates -- can count on plenty of grumbles from viewers if it chooses to pre-empt daytime soap operas and game shows in favor of something like the current Iran-contra hearings ...

Even on a day when programming is suddenly pre-empted by a fast-breaking news event, a major tragedy, a network switchboard can get as many as 1,500 angry calls in a matter of hours ...

But yesterday, the volume was way down, probably, a CBS official surmised, because there had been so much advance publicity on the appearance of Lt. Col. Oliver North on all three networks this week ...

At CBS in New York, they had received only about 300 calls complaining of the coverage by late afternoon ...

At ABC, the count was 378 complaints, shortly before 5 p.m. ...

NBC reported that between its switchboards in New York and Burbank, Calif., the network had received 12 approving calls, 232 complaining calls, and another 780 "inquiries" -- 737 recorded in Sunny California -- about what had happened to the Tuesday schedule ...

Locally, Channel 4 (NBC) reported only 49 complaints (and three calls praising coverage) by late afternoon, while Channel 9 (CBS) logged 190 complaints and another 140 from grateful viewers ...

Channel 7 (ABC) reported it had received only 63 complaints by late afternoon ...

And four calls from viewers who said that after watching North's testimony, they'd swung over to his side ...

By the way, hearing coverage is costing the networks about $1 million each, per day, in lost advertising revenues ...

You Can't Lose 'Em All

"CBS Evening News With Or Without Dan Rather" broke a five-week string of third-place finishes last week, finishing second, for a change, behind "NBC Nightly News With Tom Brokaw" ...

With viewing levels down because of the long July 4th weekend, "Nightly News" averaged a 9.7 Nielsen rating and a 22 percent audience share for the week ending July 3 ...

CBS News averaged a 9.5/22, while "ABC World News Tonight With Peter Jennings" did a 9.1/20 to fall back to third place ...

NBC's early evening news figure matched ABC's primetime performance last week and exceeded CBS' primetime rating by half a Nielsen point (or about 437,000 TV homes, on average). And "CBS Evening News" beat CBS' primetime performance by three-tenths of a point ...

Houston Nights

A week ago tonight, seven would-be candidates for the Democratic nomination for the presidency debated on PBS ... the first such nationally televised debate -- for candidates from either party -- of what already seems like a very long campaign ...

We're reminding you of this only because so few in Washington bothered to watch the debate at the time ...

According to Nielsen figures relayed by the Public Broadcasting Service, Channel 26 here had a 2.0 rating and a 4 percent audience share, which means about 31,600 TV homes were watching the two-hour "Firing Line" special from Houston that night ...

Only Hartford, Conn., with a 0.9/2, and Atlanta, at 1.7/3, proved to be less interested in the debate than the nation's capital that night ...

PBS reports that, overall, the Democrats averaged a 3.0 rating and a 5 share last Wednesday night in 14 of the 15 major markets polled by Nielsen ...

Viewers in Houston, many of whom probably had relatives in the audience at Wortham Center, turned up the biggest rating, a 6.0/9. Boston viewers, perhaps drawn by the presence of Massachusetts Gov. Michael Dukakis in the lineup, gave WGBH there a 5.9/11, the second best ...

KQED in San Francisco aired the debate on Friday night, netting a 4.1/9. (A visit to the top secret Airwaves Computer late yesterday revealed that the 15-city average for the debate, therefore, turned out to be 3.1/5. Visits to the top secret Airwaves Computer may not always turn up interesting information but they certainly help fill up space on a very slow morning. And it's also cooler down there in the Computer Room) ...

"Firing Line" will present a similar debate among Republican hopefuls on PBS the first week in September -- also from Houston ...

Is Channel 5 getting ready to announce talent changes on the 10 o'clock news show? ...

1 20.0 The Cosby Show 41 NBC

2 19.5 Family Ties 36 NBC

3 17.0 Growing Pains 30 ABC

4 16.7 Cheers 32 NBC

5 16.0 Designing Women 27 CBS

6 15.6 Who's the Boss? 30 ABC

7 15.5 60 Minutes 33 CBS

8 15.3 The Equalizer 28 CBS

8 15.3 Moonlighting 27 ABC

10 15.1 Newhart 26 CBS

11 14.6 Bates Motel 27 NBC

12 14.4 Molly Dodd 27 NBC

13 14.2 Valerie 27 NBC

14 14.1 Matlock 26 NBC

15 13.9 L.A. Law 26 NBC

13.9 Cagney & Lacey 25 CBS

17 13.6 Love Is Forever 24 NBC

18 13.5 Spenser: For Hire 24 ABC

19 13.2 ALF 26 NBC

20 12.8 C.A.T. Squad 23 NBC

NBC won in primetime for the 23rd straight week and ABC finished second for the first time since April in a holiday week marked by low viewing levels ...

NBC averaged an 11.9 rating and a 24 share for the week ending July 5. ABC recorded a 9.7/19 and CBS fell to third with a 9.2/18. The five lowest-rated programs last week belonged to CBS ...

Nevertheless, a repeat of CBS' "The Equalizer" Wednesday night jumped into a tie for eighth place for the week, adding more than 3 million TV homes to the audience it had inherited from "Magnum, P.I." at 10 as NBC countered with a special on Israel, "Six Days Plus 20 Years: A Dream is Dying," which finished 56th ("Equalizer's" showing explains some of the low viewing for the PBS presidential debate that same night) ...

In a long week of reruns, ABC's "Best Kept Secrets" was 31st, CBS' "Anna Karenina" tied for 34th and ABC's Monday night baseball tied for 41st ...

ABC's three-hour "Star Spangled Celebration" on Saturday night tied for 45th ...

The All-CBS Final But Not In Every Instance Fatal Five last week included, in order, "Dallas," in 58th place; followed by "The Wizard"; "Summer Playhouse"; plus part I of "Space" and "West 57th," which finished in a tie for 61st and last place. The last named program, which only last week received a guaranteed year's run from the network, averaged only a 4.1/10 ...