When Motown Records moved from Detroit to Los Angeles in 1971, it not only left behind its ghetto storefront offices for plush skyscraper suites, but also family spirit. The record company that had once been known for its unified, distinctive sound became just another label with some talented artists and some not-so-talented artists.

Motown developed a few new stars in the '70s -- notably the Commodores and Rick James -- but their music was as weak artistically as it was strong commercially. Motown's only artistic triumphs in its second decade came from those performers it had nurtured in Detroit: Stevie Wonder, Marvin Gaye, Smokey Robinson, the Temptations and the Jackson 5. By 1975, Motown had lost Martha Reeves, Gladys Knight, the Four Tops, all the Jacksons but Jermaine and its top songwriting team of Eddie Holland, Lamont Dozier and Brian Holland.

The story is told on the new two-record anthology, "20/20": Twenty No. 1 Hits From Twenty Years at Motown (Motown M9-937A2). To avoid too much overlap with the excellent '60s anthology, "The Greatest 64 Motown Original Motown Hits," the 20 songs on the new release contain only two songs from the '60s.

Motown's rapid decline can be traced by dating the tracks on the anthology.The 14 strongest cuts by Wonder, Robinson, Gaye, Diana Ross, the Temptations and the Jackson 5 are all clustered in the years 1969-1973. The balance of the decade is represented by tedious disco from Gaye and the Miracles and by syrupy pop from Ross and the Commodores.

Now it's 1980, and Motown is trying to recapture its past glory by turning to its past stars. The recent albums by Wonder, Robinson, Ross, the Temptations and Jermaine Jackson indicate that the label might just pull off a revival.

Berry Gordy founded Motown, Gordy and Tamla Records in 1960. He produced and composed many of the early hits. In recent years, though, he had devoted himself more to Motown's film and TV projects than its records. But he has returned to the recording studio to produce the Temptations' new album, "Power" (Gordy G8994M1).

The Temptations have gone through three periods in their career: the 1961-68 period of rich vocal harmonies such as "My Girl"; the 1969-71 period of psychedelic soul such as "Cloud Nine"; and the 1972-79 period of disco-funk such as "Papa Was a Rolling Stone." Each period marked less emphasis on vocals and more emphasis on instrumental backing. Each change of periods was also marked by the loss of a key singer: David Ruffin in 1968 and Eddie Kendricks in 1971.

Only two of the original Temptations are still in the quintet, and none of the present members has the rich voice of a David Ruffin."Power" marks a return to the group's second period. The title tune, composed by Gordy, is a throwback to the days of protest soul kike "Cloud Nine" both in sound and content. Using unusual irony, the song's narrator starts off as a revolutionary rabble rouser but ends up as a power-mad maniac.

Five of the album's seven other cuts are slow love songs done in the polished production style of early-'70s Motown. Two of the best are composed by the group itself. Though the present quintet lacks an overwhelming lead singer, all five are quite good, and Gordy blends them with the old finesse.

The songwriting team of Bernard Edwards and Nine Rodgers has the kind of sure-fire soul talent that would have naturally gravitated to Motown in an earlier era. In the late '70s, though, they signed with Atlantic Records and set up their own production company, the Chic Organization. Edwards and Rodgers compose, arrange and produce records for Chic, sister Sledge and Norma Jean. Each record has an irresistible, unmistakable Chic signature to it, just as Motown records once had.

It's ironic, therefore, that Diana Ross -- Motown's most famous artist -- should turn to Edwards and Rodgers to compose, arrange and produce her newest record, "Diana" (Motown M8936M1). It's doubly ironic that "Diana" is the best record Ross has made in 10 years. Edwards and Rodgers not only use the entire Chic band on the album, but the Chic sound as well.

Ross has always been much overrated as a singer, and the weakest cuts on the album are those slow mood songs that she tries to carry herself as if she were Carmen McRae.

The best are the upbeat dance numbers where Ross' voice is just one more instrument in the hands of Edwards and Rodgers. They surround her with quirky percussion and swaying walls of sound. Rodgers' chunky guitar chords churn up an unstoppable tornado of rhythm. Ross' light voice is carried off like a leaf by the dancing strom of "I'm Coming Out," just as her voice was carried off by "You Can't Hurry Love" 14 years ago.