I bought a "scratch and dent" DSL40CR from Musician's Friend. When it arrived, it was awesome! The only issues it had were cosmetic and it was missing a footswitch.

Fast forward two weeks later and one day I'm playing and the volume drops and there is distortion even on the clean channel. I took off the back panel and saw that one of the power tubes was not lighting up. I contacted a local repair shop and they said it was likely the tubes. When I checked the bias the power tube that was working was around 35 and the one that was not was around 0. Since I thought the issue was likely related to the power tubes, I asked Musician's Friend if they would send me some replacement ones since I was withing th 45 day return period and they did.

Well, the new tubes arrived (Ruby EL34s) and I installed them and rebiased after leaving the amp on for several minutes. Both power tubes lit up, but I still have the same issue. I'm pretty bummed because I really liked this amp and now I'm worried it's just not built very well.

On a related note: the power tubes that came with my used DSL40CR were TAD EL34-STD Red Caps; are these are not the stock tubes that come with this unit? I'm wondering if maybe the previous owner had tried to mod this amp and did something to the circuit board or something?

One other thing: I plugged in my Orange Crush Mini into the Marshall and the speaker works just fine, sounds great even! So it's not an issue with a blown speaker, it's something with the electronics would be my guess.