Philco-Radio-and-Television-Corp-T-4J 电路原理图.pdf

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1、VOLUME R-19, MOST-OFTEN-NEEDED 1959 RADIO SERVICING INFORMATION PHILCO MODELS T-4 and T-4J - CODE 124 ALIGNMENT CHART STEP SIGNAL GENERATOR RADIO ADJUST CONNECTION TO RADIO DIAL SETTING DIAL SETTING SPECIAL INSTRUCTIONS 1 Panel must be removed from cabinet. Connect signal gen erator through a .1 uf

2、con denser to antenna section of gang. Use the least generator signal necessary to give an oputput indication. 455 KC Tuning gang fully open. Adjust for maximum output in order given. Z33rd IF Z22nd IF Zl1st IF 2 Use radiating loop (See note 1 below). 1620 KC 1620 KC (gang fully open) Pre-set C2A (A

3、nt.) 1/2 turn from tight. Adjust for maxi mum output. ClBosc. trimmer 3 Same as step 2. 1400 KC 1400 KC Adjust for maximum output. ClAant. trimmer 4 Same as step 2. Panel MUST be re-mounted in cabinet. 600 KC 600 KC Adjust for maximum output. Rock tuning gang while mak- in this adjustment. Tlosc. co

4、re 5 Repate steps 2, 3 and 4 until no further improvement is obtained. Always stop on step 2. | NOTE 1. Use a 6-to-8 turn, 6-inch diameter loop made up of insulated wire. Connect to generator terminals, and place about one foot from radio loop. SCHEMATIC Due to 2nd IF transistor variations die value

5、s of resistors R6 and R7 must be selected, within limits, for optimum per formance. When transistor R186 is defective, kit number 324-8003 must be ordered. This kit contains a R186 transistor and two resistors (R6 and R7) properly matched. All three components must be replaced. The stage may be chec

6、ked 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 360 ohm collector return resistor. This voltage should be 1.12 volts, with a tolerance of approximately .12 volts. The value of R6 falls

7、within the limits of 27K to aonir NOTES All resistors are 1/2 watt, 10%, carbon. Coil resistances read with coil in circuit. Voice coil impedance = 14 ohms. Voltages measured to ground with a 20,000 ohms/volt meter under no signal condition. Emitter to base voltages were measured with positive lead

8、to emitter, except for the 1st IF which is an NPN type and measured with the positive lead to the base. Run #51 to improve low end sensitivity. The value of Rl was changed to 13,000 ohms, part number 66-3158340. Some few sets may have a 10,000 ohm resistor for Rl. cn (sec Notes) KK0A TO SS00 A 收音机爱 好者资料库 RadioFans.CN