The old city council chamber groaned with the weight of hundreds of protesters Monday night, gathered by tenants' organizations to demonstrate their support for rent controls.

About 700 tenants gathered to protest a motion made on February 5 by Councilor Thomas W. Danehy, that would have abolished controls by April 1.

Nervous about its noisy visitors, who spilled into the hall and occupied the balcony, the council moved immediately to Danehy's motion, without allowing anyone to speak on the issue.

As expected, it rejected the motion by a 5-4 margin. All four liberals voted against the bill, joined by Alfred E.Vellucci, the only independent councilor who had gone on record supporting controls.

But for much of the crowd, including the Cambridge Tenants Organizing Committee (CTOC), Hard Times and other groups, this was hardly enough. CTOC supports extension of controls to cover all units and demands that no increases be granted by the rent control board. Screams of "Let the tenants speak" and "We want real rent control" forced Mayor Sullivan to call a five-minute recess.

Huddling among themselves, the councilors decided to let Councilor David A. Wylie introduce two motions strengthening controls, and to hear testimony on them at a special meeting Thursday night at Rindge Tech.

At Rindge, the council heard two and a half hours of complaints from a crowd shrunk to 100. Tenants charged that the board had granted rent increases to landlords in spite of housing code violations, and that it favored wealthier tenants.

The council also had a beef of its own: It claimed that the state charter does not give it power to regulate the board, which is appointed by the city manager. Meanwhile, rent controls have lasted another week.

In what could turn out to be his last hurrah, City Manager John H. Corcoran--whom a majority of the city council has pledged to replace--Tuesday applauded the Charles Stark Draper Laboratory's "vote of confidence for our city's policies of economic development."

Draper, a guidance and navigation lab that receives 85 per cent of its funds from the Department of Defense and helped develop the Polaris, Poseidon and Trident missiles, announced it was joining a Boston development firm in building a $30 million Technology Square complex that will keep about 2000 jobs in Cambridge.

Corcoran said the complex, which will also house Draper's research in oceanography and other non-military sciences, will employ about 300 blue-collar workers and a thousand non-professional white-collar workers, as well as some research and development specialists.

Construction on the new complex is supposed to start around April Fool's Day, and it should be ready for occupancy late in 1975. Above, an artist's conception of the completed building in its Tech Square surroundings.