General-Electric-Co-P710B 电路原理图.pdf

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1、VOLUME R-18, MOST-OFTEN-NEEDED 1958 RADIO SERVICING INFORMATION GENERAL ELECTRIC Models P710A, -B, -C, -C, and P711A, -B, -C, -C, (Continued on the next page at right) TO REMOVE CHASSIS FROM THE CABINET Pry off the cabinet back by using a small coin in the slots provided on the bottom of the case. P

2、ull off the volume control knob. Remove the tuning knob by unscrewing the thumb screw in its center in a counterclockwise direction; then pull off the large knob. Remove the Phillips flat head screw located under the tuning dial. Also remove the two Phillips head screws located on the speaker end of

3、 the chassis. This will enable the chassis to come free from the cabinet front. This receiver is of dual chassis design. The speaker, loop antenna, volume control, and tuning condenser are mounted on the upper metal chassis. All transistors,transformers, and components are soldered on the etched cir

4、cuit board. To separate the metal chassis from circuit boar4 unsolder the two tabs that hold the volume control to the metal chassis; unsolder the lead from the loud speaker; unsolder the lead from the top lug of the tuning gang oscillator section and two loop leads to the chassis board; carefully b

5、end the two mounting lugs on the speaker end of the circuit board andone on the tuning condenser end; also unsolder the lug near the phone jack; then gently pull off the circuit board. The tuning condenser, loop antenna, and speaker will remain on the metal chassis. COMPONENT REMOVAL To remove the s

6、peaker from the radio, unsolder one speaker lead and carefully bend over condenser C13 and remove speaker mounting screw. Remove the tuning condenser by unscrewing the two mounting screws located on the face of the metal chassis. To replace the volume control,unsolder the three volume control leads

7、at tlje control and the two switch leads on the back of the control. ALIGNMENT Feed the output from the signal generator to the junction of C2 and tne loop antenna for IF alignment. For oscillator and antenna peaking, radiate a signal to the receiver by connecting a ferrite-rod antenna to the signal

8、 generator output leads. All alignment points can be adjusted with the cabinet back off. The I.F. and oscillator cores can be peaked by using the holes provided in the circuit board. Keep RF from signal generator low. It is advisable to check battery voltage before alignment to insure a proper opera

9、ting voltage. Always align the receiver with the batteries in place, as their close proximity to the loop antenna maintains the inductance constant for maximum oper ating efficiency. 1. Align all IF cores in Tl, T2 and T3. 2. With gang fully open align oscillator trimmer C1D to peak at 1620KC. 3. Pe

10、ak antenna trimmer C1C to maximum output at 1400 KC. 4. Rock oscillator core and gang to peak at 580 KC. Repeat steps 2, 3 and 4 as necessary. I L o cu X X 00 p PEAK AT 1 1620 KC Cioj C -XI (PEAK AT II400KC CIC l- g g o t-t JJ 0) u c c 0) O JS e 70 收音机爱 好者资料库 RadioFans.CN VOLUME R-18, MOST-OFTEN-NEE

11、DED 1958 RADIO SERVICING INFORMATION GENERAL ELECTRIC Models P710A, -B, -C, C, and P711A, -B, -C, -C( (Continued from the preceding page) 6e -A* * * *-1 I *n OR MWJ SK i C I B t ta T o, 0450* UNLESS OTHERWISE NOTED CAPACITORS MORI THAN 1- WMF CAPAC TORS LESS THAN l*ME RESISTORS ARE 1/2 WATT K-IOOO.

12、M *1,000,000. CHECK COLLECTOR CURRENT WITH A MIL I AMMETER INSERTED N SERIES W TM THE CIRCUITS SHOWN AT POINTS MARKED *X* IN COLLECTOR CIRCUITS AND CHECK ATTERV CURRENT AT POINT MARKEDX* IN AATTERY CIRCUIT ENM5 0R 2MC9 TRANSISTOR COLLECTOR COLLECTORp-EMITTfR AM JD mill c P7I0B P7II6 2MS5 on zms % -0

13、5 ISmaJ ) 470 0 Pn i.r - cw i -05 * 13K XS M ITiMI OR P7I0C. P7IIC RS JEN |-75 CR 2WS -T-HHIhh osc coil P7I0A, P7IIA Production Change* P710B C8- 3000mm connected to junction of C9 and CIO. C15- 50mf., 6V, connected across Rll R8 22K R12- 390 ohms See Fig. A for X3 and X4 stages. P710C C8- 3000mmf.,

14、 connected to junction of C9 and CIO. C16- 3mf. R4- 120 ohms R7 1.5 meg R8- 22K R12- 390 ohms R13- 3.3K R14- 18K See Fig. B for X3 and X4 stages. P710C| C8 3000 mmf., connected to junction of C9 and CIO. C17- 3mf. R8 22K R17- 4.7K R17 and C17 mounted to solder side of component board. See Fig. C for X3 and X4 stages. C, L . C* T*L UlUf * * mm o P7IOC P7IIC. PHONE JACK R3 C7 X3 Cll CI2 C9 Dl T3 X4 Rll R,2 T4 CHASSIS TOP VIEW 收音机爱 好者资料库 RadioFans.CN