Countdown at 50: the powerful, messy and sexy music show that changed Australia

At 6.30pm on this day in 1974, Countdown made its television debut. Perhaps it didn't cause Australia to change overnight – that really happened on 1 March 1975, when Skyhooks heralded the dawn of colour transmission in Australia on a special midnight broadcast – but it's safe to say music television would never be the same again.

This weekend and next, the ABC will celebrate the 50th anniversary of the program's appearance on our screens. Hosted by Myf Warhurst and Tony Armstrong, Countdown 50 Years On features a long list of luminaries past and present paying tribute, from 70s mainstays Daryl Braithwaite, Marcia Hines and Leo Sayer, to the likes of Regurgitator, Katy Steele and Kate Miller-Heidke.

It's not just nostalgia. Countdown maintains its hallowed place in Australian cultural memory because nothing effectively replaced it since it last went to air on 19 July 1987. Perhaps nothing ever could. "Sadly I think you'll never see a show like it again, because times have changed," Warhurst says.

It's gone down in Warhurst family folklore that in 1976, when she was a toddler, she crawled out of her brown velour beanbag to plant a kiss on the image of Daryl Braithwaite on her television screen. Braithwaite, wearing a wide-lapel blue satin jacket over his bare chest , was lip-syncing Sherbet's monster hit Howzat. "It was the beginning of a huge life journey," she says.

For Warhurst and millions of other Australian children and teenagers who grew up in the 70s and 80s – this writer included – Countdown was a formative musical education. "Countdown is one of the reasons I'm probably on the path that I followed. It was a step-off point for a lot of people," Warhurst says.

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Our guru was Ian "Molly" Meldrum, a flawed presenter but terminally enthusiastic music fan who never condescended to his audience. It didn't matter that Meldrum could barely navigate his way from the beginning of a sentence to the end. Neither could we, and so he was speaking our language. He was the eternal teenager; he was one of us.

Countdown started out as Australia's answer to the BBC's Top of the Pops, which began broadcasting in 1964, but Countdown's influence ended up spreading far beyond these shores. Long before MTV, it made heavy use of video clips, helping make stars of Abba, Blondie, Madonna and Cyndi Lauper in Australia before they took off in other countries.

With its enormous reach, it also had the power to make or break Australian talent. "We would be watching Countdown and imagining ourselves – wouldn't that be great if that was us?" says Grace Knight, singer of Perth group Eurogliders . The band, fronted by Knight and songwriter Bernie Lynch, would go on to host the program on three occasions.

Like Triple J in the 90s and 2000s, playing this curatorial role meant that Meldrum and Countdown became the subject of intense criticism, mostly for what the show wasn't and what it could never be – that is, all things to all people. It largely avoided punk; it championed hundreds of haircut bands and teen idols with short shelf lives.

But for Warhurst, who grew up in a small Victorian country town with only one television station, it was a lifeline to the outside world: "It gave us access to global artists, and Molly had the most extraordinary access. But he was also trying to establish an Australian scene that was just as valid ... I felt like it was part of a world I was involved in; I felt included."

Mark Callaghan, whose band Ganggajang became Countdown regulars in the mid-80s, also remembers Meldrum's generosity of spirit towards his earlier group, the Riptides. A couple of members of the ska-influenced new-wave outfit drove to Melbourne from Brisbane, toting copies of their single Tomorrow's Tears , and tracked down Meldrum at his home address.

"They knocked on the door, said 'Hi, we're a band from Brisbane, can we be on Countdown?' And he said, 'Yeah, give us your record', so they did. And that's how we got on Countdown – no promo, no record company, no nothing. We just asked!" Callaghan says.

In his 1993 Countdown book Glad All Over, Peter Wilmoth wrote that the show "was a pleasure against which struggle was useless". Part of the appeal was never knowing what would happen next: you would sit through the dross for the regular moments of madness, like Iggy Pop's bug-eyed appearance in 1979 . Meldrum found Iggy's antics "about as funny as a burning orphanage", Wilmoth wrote: after menacing an audience of around 200 children with the blunt end of his microphone stand during his performance of I'm Bored, the singer hurled it across the studio. It flew past the cameras, landing harmlessly.

Another extraordinary moment was the appearance of drag star Divine , dubbed "the most beautiful woman in the world, almost" by film-maker John Waters. This was another part of the show's legacy: although Meldrum himself was not out then, he helped introduce queer culture into Australian television via appearances by Elton John, Culture Club and more.

For kids in puberty, it was an awakening. "I remember watching the video for Devo's Whip It , and I knew that there was something a bit askew about it but I couldn't put my finger on it as a little kid," Warhurst says. "We were lucky in that sense, because it opened our eyes in a beautiful, lovely, gentle way."

Meldrum, now 81, will not be appearing in Saturday's performance, though he has given his blessing. A former Mensa member, amateur Egyptologist and producer of Russell Morris's anthem The Real Thing, there was always more to Molly than the stumbling caricature who famously fluffed his lines in front of the then-Prince Charles .

"When Molly said 'do yourself a favour', a lot of the radio stations added it to the playlist the next day," Callaghan says. "A lot of people, especially in the punk world, didn't have a lot of nice things to say about Ian Meldrum, but I thought he was incredible, a real music fan. He had really good intuition."

Likewise, it's easier in hindsight to see Countdown for what it really was: appointment television. "It not only connected pop music with the nation, it also helped connect families," Knight says. "They would prepare their Sundays around when Countdown was coming on, and then they would sit together and watch it. There's something special about that."