The first thing i learned: the big red transformer is very special and if it dies it is difficult/expensive to get a new one. It supplies the whole box with different voltages: 6.3V, 6.5V, 24V, 155V, 325V, 6.1V and 30V (see service manual page 13043 for more information).
My favorite part is the selenium rectifier (see picture 3), i never saw one before. I don't know yet if you can still buy these or if i can replace it with a silicon-model, i'll find out.
After consulting the Jukebox-Mailing-List-Members my next steps are:
- washing the whole unit to get rid of the sticky, dusty dirt.
- check the transformer for shorts and then test the voltages.
- replace all caps.
- replace all tubes (the 6x4 one is important, because "A short in this tube can fry the transformer. Old, "high mileage" 6X4's frequently have elements that short out." (James Alexander)
I will be back soon with pictures and informations. Stay tuned.