(Image Credit: Bob D'Amico/ABC News)

Back in the 1970s, the hit sitcom "Happy Days" looked back at the 1950s. The show depicted a kinder, gentler era, but the days since haven't all been happy for many of the show's stars.

Those stars - Erin Moran, Marion Ross, Anson Williams, Donny Most - and Tom Bosley's widow, Patricia, sued CBS last year alleging they are owed royalties from the use of their images in merchandise that includes shirts, scrapbooks, cards, games, lunch boxes, dolls, DVDs, magnets and slot machines.

The actors brought the suit after they found out about "Happy Days"-themed slot machines in Las Vegas. The plaintiffs are seeking $10 million from CBS for alleged breach of contract, Aaccording to the Hollywood Reporter.

Ron Howard, now a successful film director, and Henry Winkler, who played Fonzie, are not part of the lawsuit.

"I never received anything for all of that merchandise," Most, 58, better known to the show's fans as the character Ralph Malph, told "Good Morning America" correspondent David Wright in a recent interview.

"They had separate deals from the five of us," Most told "GMA." "Henry's been being paid for merchandise all this time. Isn't that funny Henry was paid but we weren't? So there's something not right about that."

The show's owner, CBS, tried to have the lawsuit dismissed, but a Los Angeles judge ruled Tuesday that a lawsuit brought by Moran and other "Happy Days" regulars can go to trial. A start date of July 17 was set.

Ross, who played Mrs. C, recently starred as the voice of SpongeBob SquarePants' grandmother. Williams, who played Potsie Webber, went on to direct episodes of popular TV shows including "Star Trek: Deep Space Nine" and "Xena: Warrior Princess" and "Charmed."

But things apparently have not gone as well for Moran, who played Joanie. She reportedly has had trouble finding acting work, and after losing their home, she and her husband reportedly have moved into a trailer park.

"Erin and her husband did in fact move in with her ailing mother-in-law over a year ago," Moran's publicist told ABCNews.com last week. "They are helping take care of her, as any loving family would do."

Bosley, who played Mr. C, died last year. Most still acts, and has played guidance counselor Emma Pillsbury's father on "Glee."