Galvin-Mfg-Co（Motorola）-52R12 电路原理图.pdf

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1、MANUAL OF 1953 MOST-OFTEN-NEEDED RADIO DIAGRAMS MODEL 52R11 iTj HS-289 52R12 Bull! |l I (If hi HS-289A 52R13 TO REMOVE CHASSIS FROM CABINET: I. Remove the four screws which hold the back cover remove the cover and line cord. Chassis HS-289A is the same as HS-289 except for the locations of electrica

2、l components A dual 250 mmfd ceramic capacitor replaces capacitors C-3 and C-6 used in chassis HS-289* 2. Pull off the two control knobs from the front of the re ceiver. 3. Remove the Phillips head screw under the tuning knob, on the front of the receiver. 1* The chassis of this receiver is connecte

3、d directly to the power line. However, the power cord circuit is broken by an interlock when the cabinet back is removed for replacing tubes. When aligning or servicing the chassis from AC, an isolation transformer should be inserted between the power line and the chassis. 2. Do not service the chas

4、sis on a metal plate, because of the possibility of a short circuit. 3. Use caution when handling the chassis with power ap plied, because all high voltage leads are exposed. 4. The outer edges of the chassis and the large printed areas in the center are at ground potential. 4. From the back, remove

5、 the screw which holds the line cord plug. 6. From the back, remove the three screws which mount the chassis. CAUTION: Do not lose the insulating washers on the screws -they prevent damage to the printed circuit by the heads of the screws. See Figure 1. 7. Slide the chassis from the cabinet, CIRCUIT

6、 DESCRIPTION ANTENNA The circuit of this chassis is conventional - there are no built-in resistors or capacitors. Leads are printed on both sides of the chassis base, thereby replacing the usual connecting wires and making wiring more uniform. Under certain circumstances, in early models, AC hum was

7、 induced into the loop antenna. This condition was cor rected in later models by repositioning the loop. Figure 3 shows the revised location. CHASSIS MOUNTING SCREWS I2BE6 CONV 35W4 RECT I2BD6 IF AMP r 50C5 fS I2AT6 PWR AMP VV DET-AVC-AF FIGURE 1. REAR VIEW OF RECEIVER ILATE MODEL) POWER INTERLOCK C

8、ontinued on next two pages 收音机爱 好者资料库 RadioFans.CN MANUAL OF 1953 MOST-OFTEN-NEEDED RADIO DIAGRAMS MOTOROLA, INC. ALIGNMENT Chassis HS-289, continued. NOTE: If AC power is used, insert an isolation transformer 4, Turn the receiver volume control to maximum. NOTE: If AC power is used, insert an isola

9、tion transformer between the power line and the receiver to avoid hum and electrical shocks. If an isolation transformer is not avail able, connect the low side of the signal generator to ground (the outer edges of the chassis) through a . 1 mf capacitor. I. Connect a low range output meter across t

10、he speaker voice coil. 5. Use a small fibre screwdriver for aligning the IF and diode transformers (a K-Tran alignment tool is recom mended). 6. As stages are brought into alignment, reduce the signal generator output to a level which produces less than *40 volts (, 05 watt) across the voice coil to

11、 avoid overloading the receiver. 2. Connect the low side of the signal generator to ground. 7. See Figt 3. Set the signal generator for 400 cycle, 30% modulation. chart for pr ALIGNMENT CHART 7. See Figure 2 for adjustment locations and the following chart for procedure. DUMMY STEP ANTENNA GENERATOR

12、 CONNECTION GENERATOR FREQUENCY GANG SETTING -1- IF ALIGNMENT 1. .1 mf Grid of conv. (pin 7, 12BE6) 455 Kc Fully open 1, 2, 3 & 4 (IF cores) Adjust for maximum. RF ALIGNMENT 2. .1 mf Grid of conv. (pin 7, I2BE6) 1620 Kc Fully open 5 (Osc) Adjust for maximum. 3. Radiation loop* 1400 Kc T une for max

13、6 (Ant) Adjust for maximum. Connect generator output across 5 diameter, 5 turn loop and couple inductively to receiver loop. Keep loops at least 12 apart. 1. To prevent tube hreakage, remove them before replac ing components. CAUTION: Remove the tubes only by pull ing them straight out. Wiggling a t

14、ube may bend a socket clif* causing poor contact with the tube pin. Z. WHEN REMOVING DEFECTIVE COMPONENTS USE ONLY A SMALL SOLDERING IRON (60 WATTS OR LESS) TO AVOID DAMAGE TO THE WIRING. DO NOT USE A SOLDERING GUN. WARNING: THE LEADS ARE VERY THIN, AND EXCESSIVE HEAT WILL BURN THEM OR LOOSEN THEM F

15、ROM THE BASE MATERIAL. 3. Printed connections or leads, if damaged, may be re placed with a jumper of regular hookup wire, 4. It is recommended that IF transformers, the volume control, or the electrolytic capacitor be removed hy im mersing all the lugs simultaneously into a small soldering pot. The

16、 component may then be lifted off the chassis easily. If a soldering pot is not available, heat each lug individually with a small soldering iron, and shake off as much molten solder as possible. Then, by alternately heat ing and loosening each lug, the entire component will be LI _ LOOP ANT 1400KC osc I620KC DIODE 455KC PR I (TOP) (2) SEC (BOT) (?) freed. IF 455KC PRI (TOP) (3) SEC (BOT) FIGURE 2. TUBE AND TRIMMER LOCATIONS (LATE MODEL) Continued on next page. 收音机爱 好者资料库 RadioFans.CN MANUAL OF 1953 MOST-OFTEN-NEEDED RADIO DIAGRAMS 收音机爱 好者资料库 RadioFans.CN