A ridiculously huge and powerful array of antennas spread across the planet.
NASA has a dashboard online for the Deep Space Network and you can see live which spacecraft we're communicating with. The Voyagers are usually active any time I look.
According to the article, they can send commands to Voyager 1, and it executes them, and it is still sending data back - the problem is the data coming back is gibberish (repeated patterns of 0s and 1s). They are still hoping they can work out a sequence of commands to reset its computers and resolve the problem. So it makes sense the DSN is currently talking to it.
For me, it looks like it computer damaged by interstellar radiation, which is much more energetic than solar radiation, so it's unlikely that reset will help.
According to NASA's blog [0] they believe the problem is between the FDS computer and the TMU (the outbound radio modulator). The other two onboard computer systems, CCS and AACS, they believe are still working. All three systems are dual redundant pairs of computers. So, even if one FDS was damaged, in theory they should be able to switch to the other. The blog post is vague on what exactly they tried - "the team tried to restart the FDS and return it to the state it was in before the issue began, but the spacecraft still isn’t returning useable data" - so I don't think we can rule out there are other things they can still try.
NASA has a dashboard online for the Deep Space Network and you can see live which spacecraft we're communicating with. The Voyagers are usually active any time I look.