Mr. Man, which became the first major black-owned retailer on the F Street shopping mall in 1971, has closed its doors for good.

Informed business community sources said yesterday that the clothing store never recovered an adequate sales volume after a fire gutted the store in April 1976 and kept Mr. Man closed for a year thereafter.

And the period during which owner Rufus Isley attempted to rebuild business starting last year coincided with an unusually high rate of unemployment among the city's young black male population, a significant market for downtown retailers.

Isley could not be reached yesterday to comment on the closing of his business, which began on 14th Street NW in 1968. The store at 1325 F St. NW was padlocked and shuttered, however, after Isley apparently failed to find a new source of capital to continue operations.

According to Leon Bechet, district director of the Small Business Administration, Isley "dropped off the keys" to Mr. Man at the local SBA office, which now has the task of canvassing the remaining inventory of planning an auction of merchandise and fixtures.

"I discussed current proboems with him on two occasions recently, and the only salvation appeared to be an injection of new capital, preferably equity (stock investment)," Bechet said yesterday.

Isley had established his firms with SBA loan assistance, beginning with a direct government loan of $50,000 in 1968 on which the balance is $10,000.

In 1975, when Isley expanded a then-successful retail operation, Mr. Man received a $185,000 loan from the National Bank of Washington under a government-guaranteed loan program. Banks are guaranteed a 90 percent reimbursement under that federal loan program. The balance yesterday was $176,800.

Mr. Man had generated close to $800,000 in sales during its peak year, 1974, before a decline set in during a period of soaring inflation and recession that had a major impact on the District economy.

Then, a three-alarm fire caused extensive damage to the store. D.C. fire investigators did not determine the cause of the fire, and proceeds from an insurance company policy were forwarded to Isley, according to the SBA's Bechet.

Isley, who was the SBA's "small businessman of the year" in 1970, earlier had recovered from a fire and the 1968 rioting that damaged his Upper 14th Street store. As he prepared to reopen last year, he told a Washington Post reporter he hoped Mr. Man would be stocked with a mix of quality merchandise "to get away from the stigma that most black retailers have."

But his lawyer, Ronald Jessamy, offered what turned out to be a prophetic assessment of the fire's impact when he said last year: "You never fully recover from a catastrope like that . . . he'll be years tryng to catch up on previous creditors because of the fire."

In recent months, Isley's selection of merchandise became less complete as sales volume was not adequate to support the store, several retailers noted.

The failure of Mr. Man represented a setback for local minority business enterprises and for the city's old downtown retail strip, where business has been weak for many store since the 1968 riots and subsequent subway construction. With the opening of Metro, however, a number of firms have reported substantial business gains - among them Woodward & Lothrop, which straddles a subway station.