ART TUBE MP Microphone Preamplifier

ART TUBE MP vacuum tube microphone preamplifier.

Purchased new around 2022 from Sound House, then bought on Mercari as a beautiful item used only for streaming with no malfunctions. However,
the green LED only lights up faintly, barely visible when the room is completely dark.

It's difficult to tell from the images, but photos 7 and 8 show the unit powered on and off.
The camera makes it look like there's no problem, but in reality, it's very hard to see.

The red peak light does illuminate properly, and I haven't noticed any issues with input/output levels. Even after replacing the vacuum tube with one I had, there were no noticeable noises.
I considered using it as is, but since I was looking for a fully functional unit, I decided to sell it due to lingering dissatisfaction.

Additionally, I recorded vocals with a condenser microphone and an instrument via line input once. As this was my first time using it, I cannot compare it to the same model.
If the green light had been clearly illuminated, I probably would have continued to use it without concern.

As indicated by the 2021 inspection sticker on the unit, it is not extremely old. It's in beautiful condition as it was used for streaming, but
I am selling it to someone who understands the above condition and can accept it as is (No Claims, No Returns).