Microprocessor Inventor Target of Brother’s Suit : Litigation: The man credited with inventing the computer on a chip and a sibling, an engineer who filed a “whistle-blower” suit against Northrop, are involved in a family squabble.

Gilbert P. Hyatt, the La Palma inventor who last July won a 20-year legal battle to be recognized as the inventor of the computer on a chip, is now facing litigation from another front: his brother.

Michael A. Hyatt, a 50-year-old Cerritos resident, is suing his older brother, Gilbert, for allegedly failing to turn over property that belongs to him.

Like his brother, Michael Hyatt also has achieved some degree of fame. In 1986, the former engineer for Northrop Corp., also known as Brian Hyatt, filed a “whistle-blower” lawsuit against the Century City-based defense contractor for alleged contracting fraud.

Michael Hyatt said in an interview that his brother, Gilbert, has refused to turn over funds held in a family trust and various collectibles. Michael Hyatt said the delay is jeopardizing his own costly legal fight against Northrop.

Gilbert Hyatt said that his brother’s suit, which was filed Nov. 14 in Orange County Superior Court in Santa Ana, is unnecessary. He said he would turn over the trust fund once probate on his mother’s estate closes. The probate has not closed, he said, because unrelated litigation involving the trust is pending.

Gilbert Hyatt also said he would return the property to his brother if he is willing to sign a release and receipt and pay for the cost of returning the property.

“He has his temper up and he tends to get stirred up about things,” Gilbert Hyatt said. “He is out of work and is trying to find a way to get cash to support his activities. I can’t distribute money until probate closes.”

Michael Hyatt said his brother has refused to surrender about $90,000 in a trust set up for the Hyatt children and one cousin after their mother died. Michael Hyatt also said that Gilbert has refused to allow him access to the collectibles that he asked his brother to store for safekeeping in 1987.

Though Gilbert Hyatt said his brother is jealous of his recent patent award for inventing the microprocessor, which could net him hefty royalty payments from computer-chip manufacturers, Michael Hyatt said his suit has nothing to do with the patent.

Meanwhile, Yvette Hyatt, Gilbert’s and Michael’s older sister, said she is not a party to the suit, though she believes that she is entitled to a share of her mother’s estate.

“It’s close to three years now (since she died) and nothing has happened,” she said. “The money was part of my mother’s estate, and I wish she had spent it and enjoyed it herself.”

Michael Hyatt said he needs money from the family trust to live on while he pursues his suit, which seeks millions of dollars in damages against Northrop. He claims that he has been blacklisted by the defense industry and has been unable to find work since Northrop fired him.

In his suit against Northrop, which is pending, Michael Hyatt alleges that the company knowingly manufactured defective parts for the MX missile guidance system.

Les Daly, a Northrop spokesman, said Tuesday that the company denies the charges and noted that the federal government has declined to join Hyatt’s lawsuit.