RCA-Victor-Co-Inc-T80 电路原理图.pdf

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1、MANUAL OF 1939 MODEL T-80 MOST POPULAR SERVICE DIAGRAMS Eiskt-Tube, Three-Band, AC, Superheterodyne M BAHee SWITCH VISWCD PROMTkiMT AflD 5H0WM IN A sand (MAKIMUM CruMTff?- CIOCK l.iF) POSITION. 5 6U5/6e5 VUNIMO INfil Ctmnect the high side the test-osc. to Tune test osc. to fiSK7 grid in series with

2、.01 mfd. 466 kc 6SA7 grid in series with .01 mfd. Ant. terminal in series with i 300 ohms 20 me 6 me Ant. terminal in series with 200 mmfd. Repeat step 6. 20 me (40) “C” Band 6 me (62.6) “B” Band 1,600 kc (41.76) *A* Band 600 kc (200.26) *A* Band ing for frtaximum pealToutput Lll and L12 (2ttd I-F -

3、Trans.) L9 and LlO (1st I-F Trans.) Ce (osc.)* C6 (ant.) C9 (osc.)* Cll (ant.) CIO (osc.) C3 (ant.) L? (osc.) Rock Gang * Use minimum capacity peak if two can he obtained. Check to determine that C6 has been adjusted to correct peak by tuning re ceiver to approximately 19.09 me where a weaker signal

4、 should be received. * Use minimum capacity peak if two can bo obtained. Check to determine that C9 has behn adjusted to correct peak by tuning re ceiver to approximately 6.09 me where a weaker signal should be received. Note; Oscillator tracks above signal on all bands. TUNING INOICATOR* SOPT mmmmm

5、m ABAND INDICATOR OFP LOUO (_ power-ton e-volu me CONTROL- A C o -IT RANQE-TUNINO CONTROL ewn-HtOTRH J- 4= Iew CiO Sfo I I i i I ? ? ? I VICTBOLA C5-wn ISOOKC 6iMC. 20Mr Csthode-Ray Alignment is the preferable method. Connections for the oscillograph are shown in the chassis drawing. Output Meter AH

6、gninent.If this method is used, connect the meter across the voice coil, and turn the receiver volume control to maximum. Test-Oscillator.For all alignment operations, connect the low side I of the test-oecillator to the receiver chassis, and keep the output as low as possible to avoid a-v-c action.

7、 ! Calibration Scale on Indicator-Drive-Cord-Drum.The tuning dial I is fastened in the cabinet and cannot be used for reference during alignment; therefore, a calibration scale is attached to the tuning drum. The setting of the gang condenser is read on this scale, which is calibrated in degrees. Th

8、e correct setting of the gang in degrees, for each alignment frequency, is given in the alignment table. As the first step in r-f alignment, check the position of the drum. The 240 mark on the drum scale must be vertical and directly above the center of the shaft of the tuning drum when the plates a

9、re fully meshed. The drum is held to the shaft by means of two set-screws, which must be tightened secur when the drum is in the correct position. On the inner side of the tuning drum are two projections which serve as stops to prevent extreme rotation of the gang condenser. The tunmg drum should be

10、 set so that the stop limitmg clockwisei move ment of the drum takes effect just as the gang condenser plates are becoming fuU meshed, thus eventing stress on the gang due to extreme rotatum. COMPILED BY M. N. BEITMAN. SUPREME PUBLICATIONS 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 RadioFans.CN