Back on the Set at NBC : The only tour offered by a network studio returns after a two-year hiatus. Be sure to arrive early at the Burbank facility, especially during summer.

The San Fernando Valley is home to a number of studios, including NBC, which recently reactivated tours of its Burbank facility after suspending them during the 1991 Persian Gulf War as a security precaution, then putting them on hold because of network financial cutbacks.

The new tours offer a bonus: Unlike the Johnny Carson days, tour guests are welcome on “The Tonight Show” set when the Jay Leno-hosted show is in rehearsal.

12:15 to 12:30 p.m.: Get in the mood for studio touring by checking out nearby Walt Disney Co. studios, where the architecture and exterior sets offer good viewing without requiring you to set foot on the lot. At the entrance at 500 S. Buena Vista St., you can see two sound stages; moving north, you’ll get a close-up view of the five-story ocher and brownish-orange sandstone structure that has housed Disney corporate headquarters since 1990 and is known to Disney-ites as the “Team Disney” building.

Notice that the dark green grillwork surrounding the edifice is topped by Mickey Mouse-shaped heads. Across the street is St. Joseph Medical Center, where Walt Disney died in December, 1966.

Turn east onto Alameda Avenue to get the best view of “Team Disney,” with its rotunda behind a facade inspired by a Greek temple. Some Burbank residents were not pleased when the building, designed by New Jersey postmodernist architect Michael Graves, was unveiled. The facade features 19-foot-high sculptures of Snow White’s Seven Dwarfs, who appear to hold up the roof.

Graves also designed the studio entrance, an arch between two palm trees with the Disney logo. From the entrance, you can see the sets of a Midwestern square, a church cupola and a Mickey Mouse-emblazoned water tower.

12:30 to 1:30 p.m.: About-face and walk three blocks west on Alameda to Bob Hope Drive, then head one block south to Johnny Carson Park, across the street from NBC, for a picnic lunch. In addition to grassy expanses, squirrels and wooden footbridges over trickling streams, the two-level park offers a fitness circuit donated by St. Joseph Medical Center. You can test your fitness with a number of exercises on apparatus throughout the park, including a chin-up bar and, for would-be Shannon Millers, a balance beam.

1:30 to 2 p.m.: Cross Bob Hope Drive to the Warner Street entrance of NBC. At the parking lot, you might see NBC News’ brightly colored helicopter. Like a modern-day Dorothy in Munchkinland, you’ll be instructed by signs to “Follow the chain-link path area”--it’s even painted bright yellow--which meanders around the studio and ends up at the guest relations lobby. Along the way, fans of “Days of Our Lives” will recognize the soap’s outdoor Salem Place restaurant, clothing store and movie theater set.

You’ll want to arrive at guest relations at least 15 minutes before the tour--and as much as an hour early during the peak months of July and August. You can amuse yourself by playing an interactive game in the lobby or buying mugs, T-shirts, caps or other merchandise from such NBC shows as “The Tonight Show,” “Seinfeld,” NBC Sports and (for the time being) “Cheers” and “Late Night With David Letterman.”

2 to 3:15 p.m.: The NBC Studio Tour, the only one offered by a local network studio, provides an unstaged look at whatever is happening at the broadcasting complex on any given day. No two tours are alike. Conducted by NBC pages--ours happened to be 1988 Tournament of Roses Queen Julie Myers--each begins with a video touching upon NBC’s historical highlights: The network was the first, for instance, to broadcast a television series (“Bonanza” in 1959) in color and the first to transmit regular programming via satellite (1986).

On view at the set construction facility are walls used for NBC shows locally and in New York, and for outside events such as the Oscars ceremony. Various sets for “Days of Our Lives” are erected and struck daily.

At the special-effects display case, you can see the impact of pretend bullet and bomb hits, fake building bricks and marble floors, and giant prop food. Learn about hair and makeup from a wig display, while a video demonstrates how a 20-year-old woman can be transformed into a senior citizen in a few hours. Featured at the wardrobe department are two “Days” costumes: Jennifer’s beaded lace wedding dress and Marlena’s gold lame masquerade ball gown.

By Studio 10, home of Channel 4 News, another video gives a crash course in sports programming technology, including state-of-the-art semi-trucks, traveling the globe, dubbed “Van go.” Outside are the stars’ cars and the NBC Commissary. Inside, rehearsal halls reveal performers auditioning and dancers going through their paces, all for Bob Hope’s 90th birthday special, which airs on NBC tonight.

In Stage 1, inner sanctum of “The Tonight Show,” a jeans-clad Jay Leno is rehearsing three comic bits. He frequently spends time with tour guests, who are privy, depending on the schedule, to rehearsals of the show’s musical guests.

Also fascinating is the Skypath Control facility, with its 70 or so small television monitors showing videotape feeds to NBC stations throughout the country. You’ll also pass videotape editing rooms and a commercial storage library.

After catching a glimpse of the “Days” set (if the stage door is open), proceed to the tour’s final stop, the special-effects area. You’ll learn, through guest participation, about sound and visual effects, including how KNBC’s Fritz Coleman does the weather standing before a blank blue screen and how anyone can be made to seem to fly Superman-style, cape and all.

WHERE AND WHEN

What: NBC Studio Tour.

Location: 3000 W. Alameda Ave., Burbank.

When: Hourly from 9 a.m. to 3 p.m. weekdays, with extended and weekend hours during summer and holiday seasons; closed some major holidays.

Cost: $6 general, $5.50 visitors 60 and older, $3.75 children 5 to 12, free for children under 5. Reservations available for groups of 15 or more. Free parking.

Call: (818) 840-3537.