"Boogie at the Benefit," said the sign outside the Varsity Grill Back Room in College park last week. Inside, five bands played and more than 250 people boogied. The beneficiary? The Good Humor Band.

Though it has plenty of reason not to, the six-member, country/rock Good Humor Band remains faithful to its name.

Faithful despite the fact that Mark Corvino, the drummer, is left without a drumstick. Despite the fact that Drake Leonard, the bass player, no longer has the new bass amplifier he bought early last month. Despite the fact that, according to the police report, a late-model Dodge van the band had leased> and the $10,000 worth of musical equipment in it, disappeared.

The van was found five days later, about half a mile from where it had been parked in front of band soundman Gene Payne's home in Richmond, Va. Police Detective Robert W. Kemp said there have been no arrests and that none of the equipment in the van has been recovered. None of it was insured.

To replace the equipment "will cost at least $14,000," said Payne. But that's just part of the group's financial problems. There's also the $7,000 remainding on the bank loan the band had taken to buy the equipment in the first place.

And there's also an expensive 48 hours the group spent in New York a week after their equipment was stolen. They had a two-day engagement to play at the Lone Star Cafe in Greenwich Village.

The first night there, two of the band members' cars were towed away by the New York City Police Department. It cost the band $180 to get the cars back.

The second night in New York wasn't much better. While they played inside the cafe, someone stole a borrowed amplifier from one of the band members' cars.

Indeed, the Good Humor Band has reason to be in bad humor.

But the benefit last week by four local bands - Pegasus, North Star, Smalltalk and Groundstar - brought them over $900. It's a small sum compared to what they lost, but just enough to make this month's $420 payment on the $7,000 loan and to pay part of this month's $700 payment on $1,900 worth of new speakers they just bought.

The speakers are a small start in enabling them to play once again at such places as the Rocky Racoon Saloon ad Desperados in Georgetown, the Psyche Delly in Bethesda and the Shed in Alexandria.

When the theft took place, the band was on vacation and in the midst of changing management. Mike McAdam, one of the band's guitarists "was in Greenwich, Conn., where I'd never been before, and I was in shock for about two hours (after hearing about the theft). I was on my way to Nantucket, and I turned back."

Asked how long it will be before the band is back on its feet again with new equipment, rather than borrowed equipment they are now using, McAdam replied, "Well, it's really hard to say because we really weren't on our feet when this happened. We owe the bank a lot of money. If the benefits go well, we can probably have a new P.A. system within a few months - that's if the benefits go well."

If they don't? "We're just going to keep plugging at it, that's all. We're not going to let it break us up."

Leonard, the bass player, "felt like someone had pulled the plug out from under us," when he found out about the theft. But, he continued, "We still come out swinging. You can't really let it keep you down but so long."

As for the new $350 amplifier head he had just bought. "I Mastercharged it, and I hadn't paid one cent on it yet, and I hope the guy that's using it is getting his money's worth out of it.

"I was still waiting for the case to arrive," Leonard continued. "I've got the case now, but I don't have anything to put into it."

Corvino, the drummer, who had just taken a loan for $1,600 to buy a new set of drums, said. "It took a while to sink in. Really. Actually, I didn't believe it. It was a hell of a thing to come back to after a vacation. It was a rude awakening."

But the benefit, all of the band members agreed, was a pleasant awakening.

The other four bands "jumped right up when Diane (Donnelly, the band's financial manager) asked them to help us out," said Bill Baxter, the pedal steel player. "It gives you faith in your fellow musicians."

"You really find out who your friends are when you get into a situation like this," McAdam said.

"It's great that the groups are helping us," said Corvino. "It shows what kind of people are in this business. If they ever need our help, we'll be more than glad to help them."