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一部海燕3602薄型袖珍收音机,满刻度只能收到短波电台,根据故障分析属本机振荡过强。查变频级各元件未发现可疑点。用其他方法减弱本振无明显改善。后来在振荡线圈的中心头与交连电容C_3(6800pF)之间串一只22Ω电阻,短波信号立刻消失。经实验,这一电阻不得小于10Ω,否则,不能彻底消除短波电台窜入中波段;但也不能大于50Ω,不然的话会影响中波段的
A Swift mini pocket radio 3602, full scale can only receive shortwave radio, according to the analysis of the local oscillator is too strong. Check the frequency level of the components found no suspicious points. With other methods to reduce the local oscillator no significant improvement. Later in the center of the oscillation coil and cross capacitance C_3 (6800pF) string between a 22Ω resistor, short-wave signal disappears immediately. The experiment, the resistance of not less than 10Ω, otherwise, can not completely eliminate the shortwave radio channeling into the band; but also can not be greater than 50Ω, otherwise it will affect the band