A federal jury in Baltimore convicted Joseph Shamy, one of the major owners of Maryland's beleaguered Laurel Raceway, yesterday on charges of raiding the track's treasury to pay personal debts.

The jury in U.S. District Court deliberated for more than 30 hours over a four-day period before finding Shamy guilty of mail fraud, wire fraud and racketeering charges.

Prosecutors had accused Shamy and other members of his family of reaping illegal profits from the harness racing track by awarding a $2.4 million raceway renovation contract to a company in which Shamy held a concealed interest.

Shamy's wife, Greta, and her father, Daniel Rizk, are scheduled for trial later.

During Shamy's seven-week trial, prosecutors charged that he defrauded other Laurel stockholders of their right to honest service by creating Howard Construction Co. and then awarding it a contract to replace the track's demolished clubhouse and improve the track grounds.

Shamy concealed the true ownership of Howard Construction and reaped about $1.2 million in illegal profits from the renovation scheme, Assistant U.S. Attorney Robert Schulman told the jury.

Defense lawyers, who presented no witnesses during the lengthy trial, acknowledged that their client made a profit through the companies, but argued that the arrangement was legal. The raceway got the renovation it needed with Shamy's help, defense lawyers argued.

Prosecutors also charged that in August 1977. Shamy arranged the transfer of $160,000 from a Laurel Harness Racing Association bank account in Maryland to his personal bank account in his home town of New Brunswick, N.J. and used the money to pay off a personal loan.

The convictin of Shamy, who was the track's corporate secretary, is the most recent in a series of legal, and financial problems for the raceway, a five-eights-of-a-mile harness track in Howard County. In 1977, the raceway's former president was convicted of giving directions to have the track's old clubhouse burned down.

Earlier this year, the National Bank of Washington foreclosed on the track after the Shamys' corporation defaulted on a $4.5 million loan from the bank. that capped a period in which Shamy and his family had been beset with lawsuits by banks, creditors and minority stockholders.

The National Bank of Washington now plans to auction off majority ownership in the trac, although no date has been set for the auction.

The Maryland Racing Commission has awarded racing days to the track for next year, but any new owners would be required to demonstrate their financial responsibility to the commission under special guidelines it has set up.

The Shamys first invested in the raceway in 1975 and took control of its operations in 1976.

The mail fraud charges against Shamy grew out of his use of the postal system to mail various business letters and reports in executing the scheme to defraud the stockholders. The wire fraud charges grew out of his transfer of funds between various bank accounts.