Had/have a similar problem with my Zep LE, won't boot, no VA/VNB, tried new SD cards, didn't help. Pablo at Stern (and I) think it's the CPU board but good luck getting one! They won't sell me one, and insist I go through a distributor to repair the board even though it's a couple months out of warranty and I assume I'd have to pay for it anyway. Called the distro two weeks ago, said they'd contact Stern, haven't heard anything since. Why can't I send it to Stern directly instead of going through a distro that has far more pressing matters and probably gives no shits about this? Total limbo right now. Frustrating. Hopefully you have better luck than me.