The management of NABU/The Home Computer Network announced yesterday that it plans to free itself of its Canadian parent and secure financing for an independent American operation, in an attempt to keep its new cable service to home computers in operation.

NABU's management in Alexandria said that, under an agreement with the firm's parent company, NABU Network Corp. of Ottawa, the spun-off firm will be a separate entity based in Alexandria with its own board of directors and shareholders.

NABU Network recently reported that it had lost the financial backing of its major shareholder and was seeking to reorganize or acquire new funds. The Alexandria spin-off is part of that corporate restructuring and financing, on which the parent company's survival hinges, the Virginia company said.

NABU delivers computer software programs and other information to home personal computers through cable television lines. In Alexandria, the company's U.S. test, 5 percent of cable subscribers have purchased the service in the last five months, following an extensive marketing effort.

Thomas E. Wheeler, president of the U.S. operation, said funding for the new operation will be announced shortly. "We're raising $6 million," Wheeler said. "We now have $3 million."

Wheeler said the money will be used to launch a national "rollout" of the NABU service to cable systems outside Alexandria.

Three U.S. cable companies -- Tribune Cable, Daniels & Associates and Communications Technology Management -- are likely to be involved in the new company's funding.

The spun-off firm will have the exclusive U.S. rights to NABU Network's high-speed digital broadcast technology.

The company said it expects the parent firm to license this technology for additional commercial and non-U.S. consumer applications.

The Alexandria firm plans to introduce a so-called "Universal Adaptor" in 1985, a device that will connect home personal computers nationwide to the NABU system.