yes I will cover any costs

Still for sale or gone? Thanks

The fix was just as I said. New tubes biased at 60% plate dissapation. As per the folks at Line 6

Im no EE, but that was my thought exactly. Power tubes cant be the problem, but after replacing relays didnt help I replaced the main board. Still had the switching problem. I finally called Line 6 and they knew exactly what I was talking about, told me how to fix it, and I havent had the problem si...

If your Alchemist is changing channels on its own its time for new power tubes and they need to be matched and biased correctly. Service manual says bias test points at 350mV but this isnt entirely true, it depends on your tubes, You need to read your plate voltage and bias at 60% plate dissipation ...

Recently came across this:
http://www.epanorama.rackhost.net/schem ... alkbox.GIF