The Ladder Problem

I have a pair of The Ladder filter (500 format), each mounted into a Radial The Cube 3-slot rack, alone with the Electrodyne 501 mic pre and 511 EQ.

Everything works fine, until just now, the Ladder started malfunctioning.

The HP/LP switch used to work correctly, but all of a sudden, when switched to LP there was no sound, while knobs for distortion and output still work as they should.

I’ve switched each Ladder into different slots of different racks. No help.

I’m not sure what’s wrong here, "since nothing special happened around the time the problem occurred.

Has anyone come across similar problems? or know what might’ve gone wrong?

Thanks in advance.

I can only suggest you contact Moog Music support. Even if it’s possibly out of warranty. Especially at the price these sell for…