Lawyers for Tribune-United Cable Co. won a temporary restraining order yesterday in federal District Court in Baltimore, blocking Montgomery County efforts to seize $5 million from the company and to revoke its franchise to operate the county cable television system.

County Executive Charles W. Gilchrist announced the county's actions at a news conference Tuesday after declaring that the company had "mismanaged and mishandled" the construction of the $150 million cable system.

County officials, including Gilchrist's rivals on the County Council, unanimously supported his action yesterday. "I strongly support County Executive Gilchrist's decision," said council member David L. Scull. "The cable company has failed repeatedly to live up to virtually all of its contractual promises."

But the cable expert the county originally hired to help select a cable company expressed some reservations about the executive's action.

"This question of revoking a franchise is like dropping the atomic bomb," said Carl Pilnick, a Los Angeles-based consultant. "When a community gets to the point of even threatening to revoke a franchise they are in for a long expensive battle."

Federal District Judge Herbert Murray granted the temporary restraining order sought by Tribune-United at 4:37 p.m. without a hearing, but ordered the company to post a $25,000 bond to compensate the county for the delay if the restraining order is lifted.

"We're quite pleased with the outcome," said Tribune-United lawyer Jay E. Ricks. "The judge obviously issued the order based on the strength of the arguments in our pleadings."

However, Nicholas P. Miller, a private lawyer representing the county on cable matters countered, "At this point I think it's important not to read any meaning into it. The judge hasn't heard any part of the county's case."

Murray set a hearing for Nov. 22.

"This suit is no surprise to the county," said Miller. "We expect the company to fight and to attempt to frustrate the county's efforts. This pattern of behavior is consistent to what they have done in the past."

Ricks said the company filed suit "to get the county to recognize . . . that this is an onerous contract."

"Cable television rates will be deregulated in 1986. In effect the county is arguing that we want you to invest in all the facilities and services in the contract. What it isn't recognizing is that the operator can turn around and charge whatever is necessary" to pay for them, he said. "This is a consumer issue."

Tribune-United won the right to build the system in 1982 by promising more than 100 channels of programming and an array of public services to every home in the county.

But almost from the outset, the system has been plagued by consumer problems and by what the county claims are repeated contract violations. The firm has wired about a third of the county's 228,000 homes.

Consumer complaints reached a crescendo earlier this year when hundreds of subscribers decried poor picture quality, billing mistakes, faulty cable connections and missed service appointments.

The company has been receiving more than 200 written complaints a month since April, while telephone complaints have been climbing steadily, topping 36,000 in September, according to the most recent report of the county's Cable Communications Advisory Commission.

During the first nine months of this year, the number of calls and letters as a percentage of subscribers has been falling, while the number of service visits, which peaked in August at more than 3,500, have also started to decline, according to the commission.

Cable officials cited the figures as proof the system is operating more smoothly. The company's relations with the county, however, appeared as rough as ever.

Lucille Weisberg, a county cable subscriber, said her set "would just go off for hours" at a time, and she could never get through on the telephone to report the problem. A technician finally came and "the cable has been better, I have to say," she said.