DELCO 7270405 WONDERBAR Radio für CADILLAC Baujahr 1958

The DELCO car radio shown here, with the model number 7270405 was used by CADILLAC in the 1958 model year. It is a 12 volt car radio that has AM reception. The WONDERBAR station scan was developed by General Motors in the late 1940s and was the first automatic "station scan" radio tuner of its kind. Similar in principle to a modern station scan, the driver simply sets the desired station sensitivity and then presses the WONDERBAR button on the radio. The dial pointer then begins to travel the radio scale from left to right and stops at the next station received that corresponds to the set signal strength. The entire mechanism is driven by a strong spring and is slowed down in its movement from left to right across the scale by a tow clutch. Once a sufficiently strong signal is found, the mechanism is stopped by a small relay that locks the tow clutch and stops the scale pointer or mechanism with it. As soon as the dial pointer reaches the right end of the scale, the WONDERBAR mechanism is wound up again from left to left by a solenoid coil, the spring is cocked again and the search begins again.