Philco-Radio-and-Television-Corp-T-45-126 电路原理图.pdf

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1、VOLUME R-20, MOST-OFTEN-NEEDED 1960 RADIO SERVICING INFORMATION PHILCO TRANSISTOR RADIO MODEL T-45 CODE 126 SERVICE NOTES When signal tracing, inject signal at transistor collector and limit input to keep signal across speaker below 0.275 volts. Normally, the transistors should be the last item susp

2、ected. SCHEMATIC NOTES Due to 2nd IF transistor variations the values of resistors R6 and R7 must be selected, within limits, for optimum per formance When transistor Rl86 is defective, kit number 324-8003 must be ordered. This kit contains a R186 transistor and two resistors (R6 and R7) properly ma

3、tched. All three components must be replaced. The stage may be checked as follows. The value of R6 is selected to allow the 2nd IF transistor collector to draw 2 milliamps This is checked by measuring the voltage across Rll, the 560 ohm collector return resistor. This voltage should be 1.12 volts, w

4、ith a tolerance of approximately .12 volts. The value of R6 falls within the limits of 27K to 390K. All resistors are J/2 watt, 10%, carbon. Coil resistances read with coil in circuit. Voice toil impendance = 14 ohms. Voltages measured to ground with a 20,000 ohms/volt meter under no signal condition 收音机爱 好者资料库 RadioFans.CN