The Prince William County Board of Supervisors yesterday severely weakened a proposed ordinance that would place the first local controls on cable-TV operations in the county.

"I'd say it was pretty well gutted," said Supervisor Joseph D. Reading (R-Brentsville), who suggested the modifications after declaring earlier that he opposed any cable regulation.

The action, taken during a supervisors' work session attended by representatives of the five cable-TV companies in the county and government workers, was a victory for the industry, which had lobbied against a tougher proposal. Supervisors who initially expressed support for stronger regulation called the revised ordinance a step in the right direction. It will be considered again by the board at a second work session next Tuesday but probably will not be voted on until November.

"If it doesn't do what we want it to do, we certainly will strengthen it," said Supervisor John D. Jenkins (D-Neabsco). "But it appears to protect our consumers who have suffered, and that's what we're interested in."

The proposal before the board yesterday had been drafted by the county attorney after an outcry over poor service and rapidly rising cable prices from many of Prince William's 26,000 residents with cable service.

C. Lacey Compton Jr. of Prestige Cable, the largest cable company in the county, said the revised ordinance is "what we've been looking for. It's less restrictive than ordinances in other area jurisdictions. And it addresses the problems that we've heard in Prince William County."

Although parts of Prince William County have been served by cable since 1960, the county remains one of the largest jurisdictions in the nation that has chosen not to regulate the industry.

Members of the county board yesterday scrapped a provision of the proposed ordinance that would have imposed a licensing fee equal to 3 percent of each cable firm's annual revenues.

Instead, cable subscribers will be charged an additional $1 annually, and that money will fund a cable regulator in the county's office of consumer affairs. The proposed ordinance now deals primarily with consumer-protection guarantees, spelling out service and complaint procedures.

The supervisors deleted a number of provisions in the proposed ordinance that would have required cable companies to extend their service, create public access stations and build studios for live and recorded programming.

County supervisors were deluged with complaints about cable service last winter and early this year after Prestige, which serves about 15,000 households in the Dale City area, raised rates by 80 percent and some cable signals failed just before the Super Bowl.

The complaints, which focused primarily on billing and service, have subsided since early this year, according to county officials and cable representatives.

Compton said that while the original ordinance considered by supervisors would force cable firms to raise prices for consumers by as much as 30 percent, the watered-down ordinance tentatively approved yesterday would raise prices by 5 to 10 percent.

In Northern Virginia, Fairfax City, Falls Church and Alexandria, as well as Arlington and Fairfax counties, collect fees from exclusive cable television franchises. Although the arrangements vary by jurisdiction, the fees generally represent a percentage of the firms' gross annual receipts. In return the cable companies must provide local programming and other services.