hi i have a roberts 770 (akai m8) 2 channel tube reel to reel. it is 2 single ended mono chassis and a reel to reel system. it is like brand new even had the factory qa tag on it when i got it. it worked once and now it only pushes the speakers when the source is plugged into the preamp output. when the source is plugged in correctly i get no output at all. please help.
Sorry, no help with this. The only thing I would say is, this is not an unusual circumstance for vintage gear. Caps dry out and resistors drift off value over the years. If the unit has sat in storage, vintage gear typically works once or twice when pulled out of the closet. But when slammed with 120VAC, the parts eventually take time out.
Also, if you cannot troubleshoot the component, most likely you are not in a position to do repairs on the unit since they would require test items you probably don't have. A schematic and the ability to read one and trace circuits is also required. You'll have to find a tech willing to take on vintage tube gear and hope for the best.