Admiral-218 电路原理图.pdf

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1、VOLUME R-18, MOST-OFTEN-NEEDED 1958 RADIO SERVICING INFORMATION Admiral CHASSIS 200 and 4W2 MODELS 202 215 217 218 CHASSIS IDENTIFICATION To determine whether the chassis is a 4W2 or 200 series, check the label pasted inside of the cabinet back cover. This label identifies the chassis by number. If

2、the label has been torn out or other wise removed, the chassis used can he determined hy the clearance between the printed wiring board and the top of the cabinet. On the 4W2 chassis there is enough space for storing the power line cord above wiring board. On 200 chassis, line cord is stored below c

3、hassis. ALIGNMENT When this set is aligned while operating on the AC power line, an isolation transform* r should be used. If an isolation transformer is not available, eon nee t a 1 mfd. capacitor in series with the signal generator low side to B minus (pin 7 of 1 US tube). Set Volume control to ma

4、ximum DO NOT connect earth ground to common ground (see figs. 2 and 4). 200 chossis only Dummy Antenna in Series with Signal Generator Connection of Signal Generator (High Side) Signal Generator Frequency Receiver Gang Sotting .1 mfd. capacitor Stator of antenno tuning capacitor 4S5 KC Gong fully op

5、en Loop of several turns of wire, or place genero- tor lead close to receiver for adequate signol pickup. No actuol connection (signol by radiotion) 1620 KC Gong fully open Same as Step 2 Same os Step 2 1400 KC Tune in on generator signol Same as Step 2 Same as Step 2 600 KC Same os Step 3 zw ana z

6、. _v n1c (Continued on page 5) 215 217 218 & SERVICING Replace resistors and capacitors by clipping out the defective part and leaving the pigtail leads as long as possible. Then, solder the replacement part onto the remaining pigtail leads. Remove components such as coils, IF transform ers, and tub

7、e sockets b) alternate!) heating and loosening each pin. Brush away melted solder as each pin is heated. Use a low wattage soldering iron, 35 watts or less. PROCEDURE Connect output meter across speaker voice coil. Use lowest selling of signal generaior capable of producing adequate indication on lo

8、west scale of output meter. Use a non metallic alignment tool with 3/32 wide blade to avoid splitting slotted cores on IF transformers. Repeat adjustments to insure good results. Adjustment Adjustment Type of Description Designation Adjustment 2nd IF *A, B, Moximum 1st IF C ond D output Oscillator (

9、on gong) Antenna (on gong) Antenno peoking coil Some os Step 1 Some as Step I Some os Step 1 200 chassis only Repeat Steps 3 and 4 until proper trocking is achieved. rliBil SI S2 1U5 T2 Figure I Top View of Chossis 200 Tube Locolions ond Alignment Points Shown Figure 3. Top View of Chossis 4W2 Tube

10、Locations ond Alignment Points Shown. 3V4 Figure 2 Botlom View of Chossis 200 Tube Locations and Alignment Points Shown. COMMON GROUND Figure 4. Boltom View of Chossis 4W2. Tube Locations ond Alignment Points Shown. 收音机爱 好者资料库 RadioFans.CN VOLUME R-18, MOST-OFTEN-NEEDED 1958 RADIO SERVICING INFORMAT

11、ION M JS mm M CHASSIS 200 and 4W2 MUmlrUM MODELS 202 215 217 218 (Continued from page 4) 200 Chassis 4W2 Chassis REMOVING THE CHASSIS 1. Remove Tuning knob and Volume Control knob by working them forward and off their shafts. 2. Open cover on rear of cabinet. 3. On front of cabinet, loosen, but do n

12、ot remove, two screws adjacent the tuning shaft. 4. Loosen, but do not remove, the hexriut that secures volume control shaft to cabinet front. 5. On chassis 4W2 only, remove Phillips screw that holds chassis to rear of speaker. 6. On 200 series chassis, remove the 1U4 vacuum tube. Remove the Phillip

13、s screw that connects through middle of selenium rectifier. 7. To prevent damage, hold the printed wiring board while removing the two screws and hex- nut located on cabinet front. 8. Gently lift the printed wiring board from within the case. 9. By straightening the four prongs which hold speaker frame to cabinet, the speaker may be removed. 5 收音机爱 好者资料库 RadioFans.CN