Supporters of a convention center for Prince George's County launched today a desperate effort to revive a bill that would have provided $20 million in state bonds for construction.

Fifteen delegates, including three from Baltimore and one from Anne Arundel County, took the unusual step of signing a petition that will force a vote on the proposal Tuesday by the full House.

The bill had been a near-fatal blow Friday by the House Appropriations Committee which overwhelmingly voted against the proposal for state backing.

But today supporters of the bill began frantic lobbying efforts to revive it, and evidence mounted that the center's backers were engaged in vote trading to gain favor from a generally reluctant house.

Less than two hours after Del. Raymond E. dypski (D-Baltimore) signed the petition, for instance, the Prince George's delegation responded with a resounding 17-1 vo tein favor of a Dypski proposal to prohibit the telephone company from charging residential customers for dialing 411.

Moments later, the Prince George's delegation voted 14-5 against a bill that would have offset the effects of Dypski's measure. In both cases, the Prince George's votes were the difference between passage and defeat.

Dypski said he had been asked to sign the petition, but did so "without getting any promises from them" on his telephone bill.

The three delegates who joined the Prince George's supporters in petitioning the bond bill to a vote were George J. Santoni and Hattie N. Harrison (both D-Baltimore) and Michael J. Wagner (D-Anne Arundel).

Also joining in the wheeling and dealing was Prince George's County Executive Winfield M. Kelly Jr., who met privately with Gov. Marvin Mandel and House Speaker John Hanson Briscoe today. Some members of the county's House delegation also met Mandel.

Proponents of the center reportedly also were seeking a letter of support from Baltimore Mayor William Donald Schaefer.

The bonding bill was rejected by a 16-6 vote in committee last week, and had the seldom-used petition process not been pursued, that would have been the end of the idea for this session.

But even with the last-minute trading and cajoling, the bill was still thought to lack the necessary 71 supporters to win approval in the House.

The petition move was spearheaded by Del. Frederck C. Rummage, chairman of the Prince George's delegation. Normally, a bill that is defeated in committee is not considered by the full House, but the petition signed by 15 delegates is one way to get around that first-round defeat.

There were indications the proposal will not be favorably received by the full House. Del. Charles Docter (D-Montgomery), an opponent, said he planned to offer amendments, and 29 delegates voted against even bringing the proposal before the House, although the motion carried 67-29.

Today's vote was no indication of how delegates will vote on the measure, however, Del. Robert C. Jacques (D-Montgomery) told his colleagues that "as much as I oppose the bill, we owe it to them (the Prince George's delegates)" to give them time to make their case in the one-on-one conversations that were taking place throughout the Statehouse today.