THE SENATE / ETHICS CHARGES : Probe of Durenberger Linked to Family, Financial Problems : A panel will examine his real estate and book deals for possible violations.

Sen. Dave Durenberger (R-Minn.), whose original clean image helped make him a power on health and Social Security issues, will be hauled into the dock by his colleagues Tuesday for two weeks of televised hearings on charges of financial misconduct.

The Senate Ethics Committee has found “substantial credible evidence” that Durenberger may have broken federal law and Senate rules in connection with real estate and book promotion deals and limousines provided by lobbyists. Durenberger denies any violations.

Yet as Durenberger knows, it is a rare and ominous occurrence for ethics cases to reach this trial-like stage. Only three other senators have had to go through public hearings in the committee’s 26-year history. All fared poorly.

In 1967, Thomas J. Dodd (D-Conn.) was “censured” by the Senate after such proceedings, and in 1979, Herman E. Talmadge (D-Ga.) was “denounced.” Both failed to win reelection. A third former senator accused of misconduct, Harrison A. Williams Jr. (D-N.J.), resigned in 1982 under threat of expulsion.

Now Durenberger, former chairman of the Senate Intelligence Committee, faces the possibility of similarly severe disciplinary action.

The charges against Durenberger, 55, who was first elected in 1978, involve complex dealings that stemmed largely from family and financial problems. He separated from his wife in 1985 and spoke publicly of a midlife crisis and his own “so-called flake factor.”

Meanwhile, he had growing financial burdens, including college costs for his four sons and the expense of seeing a marriage counselor in Boston. And his income was under pressure, falling from roughly $163,000 in 1983 to $93,000 in 1984. The reason: New Senate ethics rules limited the amount senators could keep from speech honorariums paid by special interest groups, dropping Durenberger’s fees from $93,750 to $20,780.

The Ethics Committee is asking whether such pressures bred improper activities in these areas:

Real estate. From 1983 to 1987, Durenberger sought and received Senate reimbursement for rent on a Minneapolis condominium in which he held an interest.

By listing his parents’ town of Avon, Minn., as his legal residence, Durenberger thought he could claim that his regular stays at the condo were “official business.” He said his lawyer was told by Senate officials that the arrangement was “no problem,” so he billed the Senate for $85 a night.

But earlier this year, Durenberger repaid $11,005 to the Senate after its Rules Committee held that the reimbursement had been improper.

Book promotion. Piranha Press published two books he wrote, “Neither Madmen nor Messiahs” (on defense) and “Prescription for Change” (on health policy). Interest groups that invited Durenberger to speak were asked to write checks to the book firm rather than pay him an honorarium, even though books were not always available at the appearances. Piranha paid the senator $100,000 in 1985-86 for the books and for giving speeches to promote them.

Senate rules capped honorariums at $52,500 during the period. Did he improperly circumvent this limit? Did he break federal law against personal use of campaign money by transferring to Piranha a $5,000 check written to his Senate campaign committee?

Durenberger said the Federal Election Commission ruled that the payments were stipends, not honorariums.

Limousine service. On his marriage counseling trips to Boston, businesses and lobbyists provided limousines. Did his acceptance violate conflict-of-interest regulations on gifts?

Durenberger said the practice apparently is not prohibited by Senate rules.