omikl

I bit the bullet and took my HD400 in to the Yamaha service centre. To cut a long story short: They can't fix it. "Spare part is not available". They were going to quote to replace the main PCB. So, I have an HD400 that seems to be en route to the landfill as there is no way to get it fixed by Yamaha/Line 6. Is there a service manual available that has circuit diagrams and diagnostic info? The technician said over the phone that the voltages on the main board were unstable.

I have a POD HD400 that has been exhibiting the same problem for over a year now. For the first 10-15 minutes after power on from cold it goes through the following: 1) Silence apart from a crackle when you hit the strings really hard 2) Sound sounds like it has a really awful heavily gated fuzz or the world's worst noise gate attached it it 3) Settles down and works properly. I suspect that a truly awful batch of capacitors was used at some point that break down and quit after 6 years or so... Dear Line 6 - I know we're out of warranty, but a technical advisory highlighting a fix would be nice.

Yeah. Same problem. I'm using a TV as my monitor, so at least I have those speakers, but not being able to use my studio monitors sort of sucks. Hurry it up please guys....

Worked for me too. Thanks guys.