General-Electric-Co-377 电路原理图.pdf

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1、收音机爱 好者资料库 RadioFans.CN MANUAL OF 1949 MOST-OFTEN-NEEDED RADIO DIAGRAMS General-Electric Models 376, 377, 378, Alignment Information NOTH IN COMMOTION WITH MfTHt AUONMtNTi (1) Use unmodulated signal. (2) Connect 20,000 ohm-per-volt meter from junction of R29 and R41. (3) Connect 20,000 ohm-per-volt

2、meter from grid pin 1 of (V5) 6AU6 limiter to chassis with a 200,000-ohm resistor in series. The resistor must be connected directly to the grid to minimize capacity loading and to isolate the meter from the i-f voltage. Keep signal generator output down so that meter indicates not more than,one vol

3、t at the grid (5 microamperes through 200,000 (dims) (Alignment Steps 7 through 13). (4) Use 400-cycle modulation (Steps 1, 2, 3, IS, 16, 17, and 18). (5) Connect a standard output-meter across speaker voice coil. Turn volume control full on. Keep signal generator output down so that meter indicates

4、 not more than l/i watt output (1.26 volts) during alignment. (Steps 1, 2, 3, IS, 16,17 and 18.) (6) Two oscillator settings will give response. The higher fre quency response is the correct one; the other is the image response. If in doubt, start with the trimmer screw loosened completely and adjus

5、t for the first response. (7) For alignment of the standard band oscillator and r-f trimmers, the input signal should be inductively coupled to the radio loop antenna by connecting a 4-tum, 6-inch diameter loop of bell wire across the signal generator terminals, and then locate the loop about one fo

6、ot from the radio loop antenna to prevent possible errors in peak readings. The position of the loop in respect to the radio loop antenna should not be changed during any one set of adjustments. Steps 15, 16, 17 and 18. (8) The lead from the signal generator must be kept as short as possible and it

7、must be kept away from later stages to prevent regeneration. The signal may also be fed in to the tube pin con nection from the top of the chassis to prevent regeneration. (9) A dummy antenna is a resistor in series with the hot lead of the signal generator. The resistance of the resistor plus the t

8、ermination impedance of the signal generator should equal 300 ohms. (10) If a dial scale is not available, index the dial pointer as follows: Turn the pointer to the left-hand limit of travel and mark the dial plate at a reference edge of the pointer slide. Then set the pointer by turning the dial k

9、nob until the indicated dimension exists between the reference edge and the mark. ALIGNMENT CHART STEP SIGNAL GEN ERATOR FRE QUENCY SIGNAL INPUT POINT BAND SWITCH DIAL SETTING ADJUST SEE NOTE REMARKS AM l-F MfTHt AUGNMfNT 455 kc Conv. grid directly thru .01 mfd 455 kc Conv. grid directly thru .01 mf

10、d 455 kc Conv. grid directly thru .01 mfd FM DffatlMMATOft AND l-F 10.7 me Pin 1 of V5 (6AU6) thru .01 mf FM Detune sig nal generator Pin 1 of V5 (6AU6) thru .01 mf FM As in Step 5 Pin 1 of V5 (6AU6) thru .01 mf FM 10.7 me Pin 1 of V4 (6AU6) thru .01 mf FM 10.7 me Pin 1 of V3 (6BA6) thru .01 mf FM P

11、eak C47 and 4, 5 Adjust for max. C46 Peak C33 4, 5 Adjust for max. , 5 Adjust for max. 2 lApply 1 volt signal input. 9 110.7 me iPin 7 of V2 (6BE6) thru .01 mf I FM m R-F MfTHt AUONMUNT 1, 2 Detune signal generator to point of maximum meter reading. 1,2 Adjust for max. , 3 Adjust for max. , 3 Adjust

12、 for max. C21 and C20 | 1, 3, 8 I Adjust for max. 98 me Dipole terminals thru dummy antenna FM 98 me or 3?V inches Peak C62 98 me Dipole terminals thru dummy FM For max. Peak L4 vane antenna output 12 Repeat step* 10 and 11 until no further improvement in sensitivity. 13 98 me Dipole terminals thru

13、dummy FM 98 me Peak LI vane 1, 3,9 antenna 14 Repeat steps 10, 11, and 12. AM ft-F MCTHt AUGNMtNT 1500 kc Inductively coupled STD 1500 kc or 5 inches 1500 kc Inductively coupled STD For max. output 17 Repeat steps 15 and 16 until no further improvement in sensitivity. 18 Il500kc I Inductively couple

14、d I STD 收音机爱 好者资料库 RadioFans.CN MANUAL OF 1949 MOST-OFTEN-NEEDED RADIO DIAGRAMS General-Electric .Models 376, 377, 378, Alignment continued AM l-f VISUAL AUOMMSM1 1 455 kc 20 kc at 60-cycle sweep Conv. grid directly pin 7 V2 (6BE6) thru .01 mf AM C47 and C46* B Adjust for max. amplitude and min. dis

15、tortion of curve on scope screen. 2 Same as Step 1 Same as Step 1 AM C33 E| Same as Step 1. 3 Same as Step 1 and 2 Same as Step 1 and 2 AM C23 and C22 . B Same as Steps 1 and 2. H* l-f VISUAL AUOMMSMT 4 10.7 me ,3 me at 60- cycle sweep Conv. grid directly pin 7 V2 (6BE6) thru .01 mf FM C45 and C44 1

16、, 2, 11 Adjust for max. amplitude and min. distortion. 5 Same as Step 4 Same as Step 4 FM C31 and C30 1, 2, 11 Same as Step 4. Same as Steps 4 and 5 Same as Steps 4 and 5 FM C21 and C20 1, 2, 11 Same as Steps 4 and 5. DfSOUMINATOR VISUAL ALIGNMENT 7 10.7 me =*= .3 me at 60- cycle rate Conv. grid dir

17、ectly pin 7 V2 (6BE6) thru .01 mf FM Primary of T5 discrim, trans former 1, 3, 11 Adjust primary for max. amplitude. 8 Same as Step 7 Same as Step 7 FM Secondary of T5 1, 3, 11 Adjust secondary for vertical symmetry with respect to mid point horizontal traces. 9 Same as Step 7 Same as Step 7 FM Prim

18、ary of T5 1. 3, ii Adjust for straightest possible slope of straight line trace. m K-r VISUAL AUOMMSMT 10 98 me Note 6 Dipole terminals thru dummy antenna FM 1 98 me or 3A in. Adjust C62* Set dial pointer accurately, then adjust for steepest slope of straight line trace on scope. 11 98 me Note 1 Dip

19、ole terminals thru dummy antenna FM 98 me Peak L4 vane 1, 2, 9, 10 Center response curve on scope, then peak for max. amplitude. 12 98 me Note 1 Dipole terminals thru dummy antenna FM 98 me Peak LI tuning vane 1, 2, 10 Peak for max. amplitude. AM K-S VISUAL ALIGNMENT 13 1500 kc Note 6 Antenna thru 2

20、00 mmf STD 1500 kc or 5 in. Adjust C12 D Adjust Cl 2 for steepest slope of straight line trace on scope. 14 1500 kc Note 5 Antenna thru 200 mmf STD 1500 kc Adjust C16 B Adjust C16 for max. ampli tude. 15 1500 kc Note 5 Antenna thru 200 mmf STD 1500 kc Adjust C6 4, 5, 7 Adjust C6 for max. ampli tude.

21、 NOTES IN CONNECTION WITH VISUAL ALIGNMENT TABLE; (1) Use FM signal modulated at 60 cps 300 kc. (2) Connect vertical plates of scope to the limiter grid (pin 1 of V5) (6AU6) through 200,000 ohm resistor. (3) Connect vertical plates of scope to the junction of R29 and R41 (FM audio) through 200,000 o

22、hms. (4) Connect vertical plates of scope at junction of R13 and C28 (AM audio output) through 200,000 ohms. (5) Use FM signal modulated at 60 cps 20 kc. (6) Use a 60 cycle amplitude modulated signal. (7) If a dial scale is not available, index the dial pointer as fol lows: Turn the pointer to the l

23、eft-hand limit of travel and mark the dial plate at a reference edge of the pointer slide. Then set the pointer by turning dial knob until the indicated dimension exists between the reference edge and the mark. (8) Two oscillator settings will give a response. The higher fre quency response is the c

24、orrect one, the other response is the image. If in doubt, start with the trimmer screw loosened com pletely and adjust for the first response. (9) In some cases tuning of the converter grid will cause “pull ing* of oscillator which will change the oscillator frequency. After centering the response c

25、urve on the scope, if peaking of L4 causes the response curve to move off of the screen it is necessary to realign the oscillator for calibration. (10) A dummy antenna is a resistor in series with the hot lead of the signal generator. The resistance of the resistor plus the termination impedance of the signal generator should equal 300 ohms. (11) Leads from the signal generator must be kept as short as possible and away from later stages to prevent regeneration. The signal may also be fed to the tube pin connection from the top of the chassis to prevent regeneration. 收音机爱 好者资料库 RadioFans.CN