Philco-Radio-and-Television-Corp-E-818 电路原理图.pdf

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1、VOLUME R-17, MOST-OFTEN-NEEDED 1957 RADIO SERVICING INFORMATION PHILCO E-748 and E-818 98 收音机爱 好者资料库 RadioFans.CN VOLUME R-17, MOST-OFTEN-NEEDED 1957 RADIO SERVICING INFORMATION PHILCO Models E-748 and E-818 (Continued from preceding page) CHASSIS REMOVAL - MODEL E-748 CHASSIS REMOVAL - MODEL E-818

2、I- Remove knobs. Remove (2) 1/4-in. hex head drive screws from cabinet back. Disengage A.C. interlock. Remove back by freeing clock time set shaft and then swivel back around left side. 2. Remove (2) 1/4-in. hex head drive screws from top corners of dial back plate. 3. Remove (2) l/4-in. hex head dr

3、ive screws from cab inet bottom. 4. Remove (2) 1/4-in. hex head drive screws from rear bottom of chassis frame. 1. Remove knobs. Remove (6) Phillips head wood screws from back. Disengage A.C. interlock. Remove back by swiveling toward left. 2. Remove (2) 1/4-in. hex head screws and washers holding A

4、.C. interlock bracket. 3- Unsolder the two leads, from receiver panel, from the right hand speaker. 4. Remove (4) 1/4-in. hex head drive screws that mount set to cabinet front from the chassis bracket. Tie Lu No. LI -. L2 . L3 . L4 . LS L6 . L7 . L8 E-748 Connection . A-G-C to Ant. and Gang Filament

5、 side of A-C Switch Detector Output ta Jl .Arm of Volume Control Volume Control Return to B A-C line, line side of A-C Switch, and Black lead from T2 One side of Pilot Lamp A-C line and one side of Pilot Lamp L9 . Blue lead ta T2. Outpul Transformer L10 Orange Lead to T2 Lll . Brown lead to T2 L12 R

6、ed lead to T2 L13 . Oscillator section of Gang L14 .- .Ant. and Ant. section of Gang Dial Cord Stringing Model E-818 E-818 Connection A-G-C lo Anl. and Gang Not used Detector Output lo J1 Arm of Volume Control Volume Control Return to B Set side of A-C Switch, one side of Pilot Lamp, and Black lead

7、from T2 A-C line Not used Red lead to T2, Output Transformer Brown lead to T2 Blue lead to T2 Yellow lead to T2 Oscillator section of Gang Ant. and Ant. seclion of Gang Composite Base View - Models E-748 and E-818 ALIGNMENT PROCEDURE Radio Controls Set volume control to maximum. Set Signal Generator

8、 Connect generator and set frequency tuning control as indicated in chart. as dicated irr chart. Use modulated output, 30%. Output Meter Connect across voice coil terminals. Output Level During alignment adjust signal-generator output to hold output-meter reading below .5 volts. ALIGNMENT CHART SIGN

9、AL GENERATOR RADIO STEP CONNECTION TO RADIO DIAL SETTING DIAL SETTING SPECIAL INSTRUCTIONS ADJUST 1 Ground lead to 8 ; output lead through a .1 mf condenser to grid (pin 7) of 12BD6. 455 kc. Tuning gang fully open. Adjust tuning cores, in order given, for maximum output. TCI and TC3 are located on t

10、op of transformers. TC4- 2nd if sec. TC32nd i-f pri- TC21st i-f sec. TCI1st i-f pri. 2 Radiating loop. (See note below). 1620 kc. 1620 kc. * Adjust for maximum output. Cl-Bosc. 3 Same as Step 2. 1500 kc. 1500 kc. Adjust for maximum output. Cl-A-aerial. Note: Make up a 6-8 turn. 6 inch diameter loop

11、from insulaicd wire, connect to signal-generator leads, and place neor radio loop. * For proper adjusiment of the oscillator trimmer, fully open the tuning gang and insert a .008 inch non-metallic shim between Ihe heel of the rotor and ihe top of the stator plates. Close Ihe tuning gang sufficiently to hold Ihe shim in place, and then remove the shim without disturbing the gang setting. 99 收音机爱 好者资料库 RadioFans.CN