Philco-Radio-and-Television-Corp-T-45-124 电路原理图.pdf

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1、VOLUME R-20, MOST-OFTEN-NEEDED 1960 RADIO SERVICING INFORMAT ION PHILCO TRANSISTOR RADIO MODEL T-45 CODE 124 PANEL (CHASSIS) REMOVAL 1. Remove the followingTuning and volume control knobs, cabinet back, batteries, two tri-mount fasteners at speaker end of panel, battery contact and retaining board,

2、and the private listening jack from its cabinet mounting position. 2. Open the ground connection from the on-off switch to the speaker. 3. Remove the panel from the cabinet by first lifting up on the speaker end of the panel. BATTERY VOLTAGE AND TYPE6.0 volts from 4 penlight cells, type AA”, P-15, o

3、r mercury type AA”, P-9. SCHEMATIC NOTES CAUTION Due to 2nd I-F transistor variations, the value of resistor R8 must be selected, within limits for optimum performance. When transistor T-1504 (or T-1542) is defective and must be replaced, resistor R8 must also be changed unless the original provides

4、 the proper resistor operating characteristics. Failure to select the proper resistor can shorten the life of the transistor or seriously affect receiver operation. The value of R8 is selected to allow the 2nd I-F tran sistor collector to draw 2 milliamps and will be between 18,000 to 33,000 ohms. T

5、his is checked by measuring the voltage across RlO, the 560-ohm collector return resistor. This voltage should be 1 12 volts, with a 10% tolerance (.12 volt). All resistors are Vi watt, 10%, carbon, except R8 which is 5%. Coil resistances read with coil in circuit. Voice coil impedance = 14 ohms. Vo

6、ltages measured to ground with a 20,000 ohms/volt meter under no signal conditions. NV cJ, Rl._ _ IAstt.1 R7- Re 72 -8 4- I -H R3 ! .Vi * ii1 v ij ,7 ,_SJ l , iC j; i; - .ci w t x SR9 ! Z3 1 jiratffeT v: i J j 9 a ; RiSSjNk Vf fpRio lI fi # :7 J j: , , *? m2 X v. .1 n : A 1.cirvS ( . M XQS1* X-rcT- X. 3 *3V - TaoJ- output Composite Bottom View T-. / ir# f R12_ y- T-1505 AUD OUTPUT I.F. KC, Schematic Diagram of Model T-45Code 124 收音机爱 好者资料库 RadioFans.CN