The light-up "on" indicator bulb went out on my 2:90 a few years ago, and I've never gotten it replaced. I have thought of doing so and don't know what size or whever is supposed to be used (if its universal between all amps or what), but I'm also wondering if getting an LED retrofit would not only be possible, but would it be in any way helpful? Maybe it would be brighter (more ZAZZ!)?