RM50 has no sound when turned on...

fishstick_kitty · Jul 10, 2012

Well, went to band practice tonight and turned on my faithful RM50 (I've used it for a few years issue free). The lights come on (selected channel lights)...but absolutely no sound. It's like the amp is off. I checked the power tube fuses and they look good. Power tubes stay cold.

I checked cables, etc. A known good cable plugged right into my working guitar...nothing. If I tap the end of the cable...nothing. Plug the cable and guitar into another amp and it works fine.

Any ideas?

Mattfig · Jul 10, 2012

Do you have another set of power tubes to try? Although seems like it could be something more sinister....I hope not...But that's what I would try...

fishstick_kitty · Jul 10, 2012

Mattfig said:
Do you have another set of power tubes to try? Although seems like it could be something more sinister....I hope not...But that's what I would try...

I have 1 extra power tube...I'll try to put that in one of the sockets. The tubes that are in there are brand-freaking-new

. I used the amp last week (with the new tubes) w/ no issues...then turned the amp off, unplugged it from the wall and left. Came back last night, plugged it back in and it didn't make any sound at all

Mattfig · Jul 10, 2012

fishstick_kitty said:
Mattfig said:

Do you have another set of power tubes to try? Although seems like it could be something more sinister....I hope not...But that's what I would try...

Click to expand...

I have 1 extra power tube...I'll try to put that in one of the sockets. The tubes that are in there are brand-freaking-new . I used the amp last week (with the new tubes) w/ no issues...then turned the amp off, unplugged it from the wall and left. Came back last night, plugged it back in and it didn't make any sound at all

Hmmm...The whole thing is odd and it sounds like you tested out many common variables...

When you replaced the power tubes...Was it due to a fading or loss of power in the previous set of tubes? Or just time for a change? Did you change the type (EL34, 6L6) of power tube?
I gotta ask just to be safe, did you reset the bias after changing tubes?

I'm sure one of the modders or Bruce Almighty could assist with more accuracy and better info than I...

fishstick_kitty · Jul 10, 2012

Mattfig said:
Hmmm...The whole thing is odd and it sounds like you tested out many common variables...

When you replaced the power tubes...Was it due to a fading or loss of power in the previous set of tubes? Or just time for a change? Did you change the type (EL34, 6L6) of power tube?
I gotta ask just to be safe, did you reset the bias after changing tubes?

I'm sure one of the modders or Bruce Almighty could assist with more accuracy and better info than I...

Why new tubes...good question: About a month ago, the amp had a "burning electrical ozone" smell and then started kinda distorting with lower volume output. I usually play clean...absolutely no dirt...so it was noticeable. I took it to my local tech and he determined that one of the power tubes had gone bad. He replaced both with a matched set of 6L6s (same as before) and I picked the amp up. I used it for 2 gigs/rehearsals since then and it sounded great...and then this new issue happened.

I did talk to the tech about biasing and I was convinced that he knew what he was doing. When I take the new power tubes out and look at them, they still look brand spanking new...but I'm not sure if they would "look" blown.