D.C. Del. Walter Fauntroy was clearly headed for victory yesterday, easily outstanding token ballot showings by broadcaster Roger Mudd, Redskins quarterback Joe Theismann and mayoral hopefuls Marion Barry and Sterling Tucker.

The only problem, according to aides for the D.C. Board of Elections and Ethics, is that Fauntroy, who everybody knows - or should know - is a Democrat appears to have aced out 130 write-in candidates to become the Republican Party's nominee for D.C. delegate.

"People have no idea what goes on after an election," an exasperated Mary Rodgers, the board's elections administrator, said yesterday as she scrutinized Republican ballots from Ward Three.

"We would have been so grateful to have any name on the balllot." Rodgers said, adding that the absence of a challenger to Fauntroy in the delegate race seems to have encouraged Republican voters to make their own write in choices no matter how illogical.

Fauntroy could not be reached for comment but would likely be pleased to accept the local GOP's nomination to Congress as a nonvoting delegate.

Rodgers and 15 to 20 election aides completed their sixth straight day yesterday of tedious, time-consuming voter registration research designed to resolve the problem fo write-in candidates and determine the eligibility of about 4,600 challenged ballots in last week's District primary elections for delegate, mayor and City Council.

"We're making every effort to give everyone their vote," said Rodgers, who added in an unguarded moment that she and other exhausted election and go home.

The challenged ballots and some 1,000 absentee ballots will be counted tomorrow and should then provide the definitive vote totals in a close mayoral race and two even closer contests for council seats.

As part of efforts to determine voter eligibility, the board today published in The Washington Star names of more than 500 voters whose challenged ballots have been tentatively rejected because the panel was not able to verify their registration after a records search. More names will be published as the board completes research, and the challenged voters will then have a date on which to show proof of their registration.

For Phil Ogilvie, an election count observer for Councilman Marion Barry, the voter certification process has been particularly grueling. Barry is leading Council Chairman Tucker by barely 1,100 votes, with incumbent Mayor Walter E. Washington trailing a close third.

"We don't want there to be any question of hanky panky," said Ogilvie, who does not expect the absentee and challenged ballots to change the election's outcome.Ogilvie, who has kept watch whenever the aides sort through the ballots - in most cases all day and into the evening - said attendance by watchers for Barry's two rivals has been "spotty".

He said he has assured the election aides that he will try to persuade Barry to include funds in the city budget for computer equipment that would speed up voter registration research, which now is done manually.

But three are occasional bright moments that come with the job, according to Rodgers. She particularly remembers what she called "one of the most intriguing write-ins" she has come across. "Somebody in a past election wrote in the name, Ebeneezer Pennysqueezer. Now that was a good one."