If you see any of these signs, plan on repairing the set before you play it. If your radio passes a cursory visual inspection, you should next remove its chassis from the cabinet for inspection. Before you remove anything , however, get out some baggies and masking tape, so you can label every piece as you remove it. If things look complicated, snap some Polaroid pictures, make a sketch, or take notes to guide you in reassembling your treasure. If at any time you hit a bad roadblock or feel like you're in over your head, don't be ashamed to reverse your steps and let a professional take over.
Many knobs slide off using gentle pressure.
Check before pulling, however, in case there's a little setscrew securing the knob to its shaft. As you slide the chassis out of the cabinet, be careful not to break any wires leading to antenna, speaker, or other components on the cabinet. If you need to disconnect any wires, label both sides of the connection to guide you in reassembly. If the radio chassis is dirty, take this opportunity to whisk away dust with a soft brush. You may be tempted to polish dirty glass tubes, but that doesn't matter.