My JVM410H broke within a year. Get all new tubes. It wasn't a tube issue.
Garbage pickup is every Monday, so I imagine it's in a landfill somewhere. IMO, it wasn't worth the headache of trying to find a tech and dump more $$ into it.
The time I had it, I spent more time turning knobs, searching for tones that weren't there.
The Clean (green) was cool as a pedal platform, although, on that channel, the tone controls are "before" the preamp, ala Fender. I didn't buy a Marshall for Fender sounds that were anemic compared to an actual Fender amp. I found orange and red modes usesless.
The Crunch channel had no gain. Again, anemic.
I only really liked OD 1 (orange) you could basically live on that channel if you set it up right.
OD 2, with it's altered midrange blew.
With any Gain knob past noon, you start losing the ability to turn your guitar's volume down for cleanup.
This amp needs to be revamped, IMO. I would NEVER buy another though. Marshall can shove their garbage up their collectives asses.