After a Tuesday morning drive that was a morning dry for KEXP‘s traditional radio listeners, the Seattle station is back on the air with its over-the-air signal. But not before the station discovered its analog broadcast was at the mercy of digital technology.

The roughly 90-minute absence from the airwaves was caused, according to the station, by the failure of a memory card perhaps more familiar to those with digital cameras.

“Our transmitter OS runs on a CompactFlash card,” Jamie Alls, KEXP chief engineer, told GeekWire. “It’s been there for 11 years, and it just chose this morning to crap out. Luckily we were able to get the backup transmitter working, and this issue shouldn’t come up again anytime soon.”

The nonprofit indie and alternative station abruptly lost the signal broadcasting from its towers in the Capitol Hill neighborhood at approximately 8:40 a.m. It stayed off the airwaves until about 10:10 a.m. That was no problem for the large audience that listens to KEXP’s digital streams from its website, or through a service like TuneIn that feeds everything from a smartphone to a Sonos or Echo speaker. But it was an issue for those who listen on radios in cars and elsewhere, and who took to Twitter to express their dismay.

Where my @kexp ? 😭😭😭 — Space Force Cadet Erin (@ventogrrl) September 11, 2018

The station says it is again operating at full power after manual re-routing to the backup transmitter, but its single HD broadcast channel won’t return until the main transmitter does. KEXP expects to switch back to the main transmitter in the next day or two. That will result in about an hour of additional downtime for traditional radio listeners.

While KEXP estimates its terrestrial broadcast audience is about twice as large as its worldwide streaming listenership, the Tuesday morning digital-only show soldiered on.

“We know tons of people were listening via the KEXP app and KEXP.org, because when we gave away tickets to see our exclusive in-studio with Ben Gibbard tomorrow, our text-to-enter app blew up,” said Owen Murphy, KEXP morning show producer. “It’s awesome to know we have that kind of relationship with the community, even when the broadcast signal is down.”

For those who wonder, CompactFlash memory dates back to 1994 and is considered one of the most successful of the early memory card formats. It remains in use for some digital cameras.