|An EZ Tube amp repair trick.|
The single power tube glowing red. Obviously it doesn't have any bias, or the tube is bad. Very few people think of this easy repair trick.
Wait until the red hot tube cools down. Then switch it with another identical tube in the amp. Does the problem go with the tube or stay with the socket?
If it goes along with the tube, you have a bad tube - if it stays with the tube socket, that is, the other tube glows red in that socket, the socket may have a problem.
Most likely, the leaves inside the tube socket are not making contact with the tube pins. Very, very common. Various tubes, new and old, have slightly different sized pins.
Get the amp out of the chassis so you can work on it, unplug everything, and work on the tube sockets. Look down inside and find the thin metal contacts. I use an old jewelers screwdriver (very thin) to bend them inward so they grab the tube pins better. Then clean with a quality cleaner (Caig is our favorite) and plug your tubes back in.
Check it out - you may have fixed a serious problem very easily.