RCA-Victor-Co-Inc-RP-178 电路原理图.pdf

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1、MANUAL OF 1949 MOST-OFTEN-NEEDED RADIO DIAGRAMS RCaVictor RP-178 Series Automatic Record Changer Service Data Continued on the next seven pages RADIO CORPORATION OF AMERICA RCA VICTOR DIVISION CAMDEN. N. U. S. A. RP-178 Series Record Changer BP 178 Uses 117V. 60 cycle motor. For operation on 50 cycl

2、e power supply; a spring. Stock No. 73158 is added to the motor shaft. Used in the following models: 8TV321. 8TV323. 8V7, 8V90. 8V91, 8V112, 75ZU. 77U. 77V1. RP-178 2 Uses 117V. 25 cycle motor. Used in instruments manufactured by RCA Victor Company Limited (Canada). RP-178-3 Uses 117V./234V. 60 cycl

3、e motor. For operation on 50 cycle power supply; a spring. Stock No. S-4774 is added to the motor shaft. Used in Models 6QU3 and 6QV3. Index Function of Principal Parts . Adjustments . Tone Arm (Out of Cycle) Height Adjustment . Tone Arm Height Adjustment While in Change Cycle Pickup Landing Adjustm

4、ent . Record Push Cam and Gear Assembly Adjustment . Removing Turntable . Replacing Turntable . Turntable Centering . Cycle of Operation .*. Illustrated Service Hints . Pickup Repeats Grooves . Continuous Tripping . Premature Tripping . Failure To Trip or Go Into Cycle . Changer Will Not Complete Cy

5、cle . Records Do Not Separate or Drop Properly . Distorted Output . Wow or Slow Turntable Speed . Improper Pickup Landing . Rumble . AUTOMATIC OPERATION 1. With the power switch in the off position slide the record support shelf as required for 10- or 12-inch records. 2. Place the records to be play

6、ed in a stack with desired se lections upward and in proper sequence with the last rec ord on top. Load them on the changer by placing them over the center post and resting on the record support shelf. Place record stabilizing clamp on top of the record stack. 3. Turn power switch on and press the r

7、eject button. The changer will play automatically one side of each record in the slack. The tone arm can be moved to the rest position any time the mechanism is not in cycle. 4. Turn the power switch off. lift the stabilizing clamp and remove the stack from the turntable by placing fingers of both h

8、ands directly opposite and under the stack. Then lift straight up“dont tilt or squeeze stack. MANUAL OPERATION 1. Slide the record support shelf in towards the center post for 10-inch or away from the center posl for 12-inch posi tion. 2. Place the record to be played on the turntable and turn the p

9、ower switch on. 3. Place the pickup on the start of the record. Note: The mechanism should be allowed to complete cycle before attempting to move lone arm to the rest po sition. 4. Turn power switch off manually. 5. Remove the record by raising straight up withoul tilting. FEATURES 1. This mechanism

10、 is designed to play automatically a series of twelve 10-inch or ten 12-inch standard records of the 78 r.p.m. type. 2. It will play manually records up to 12 inches in diameter. 3. Tripping system is of eccentric type, insuring reliable automatic operation on all records made to RMA proposed standa

11、rds. 4. It is a simple operation of sliding the record support to change from 10- to 12-inch records or vice versa. 5. Cycling mechanism is disconnected completely while rec ords are being played. This reduces the load on the drive motor, thereby reducing the tendency for wow or rumble. 6. Low noise

12、 sapphire point pickup cartridge. CAUTIONS 1. Avoid handling the tone arm or sliding the record support assembly while mechanism is in cycle. 2. Never tum the power switch off, leaving the mechanism in cycle for an extended period of time. 3. Do not allow the records to remain on supports when not i

13、n use. 4. Do not allow oil or grease to come in contact with any rubber parts. 5. Do not install instrument near source of heat. Excessive heat may damage the pickup cartridge. Ill 收音机爱 好者资料库 RadioFans.CN MANUAL OF 1949 MOST-OFTEN-NEEDED RADIO DIAGRAMS RP-178 SERIES CENTER POST MOUNTING SUBASSEMBLY

14、MOUNTING BOLTS TONE ARM BUTTON 79 RATCHET LEVER 63 TONE ARM DIRECTOR LEVER 71 SPRING 11 PICKUP CABLE 22 RECORD PUSH CAM SHAFT LEVER 5 RACK LEVER 10 LOCATING LEVER 12 AND LATCH 50 B PUSH CAM GEAR 7 LEVER 67 Figure 1 FUNCTION OF PRINCIPAL PARTS Trip Lever67 When the sapphire is riding the eccentric gr

15、oove, the trip pawl engages the ratchet lever, starting cycle. Ratchet Lever63 Portion of the lever acts as a ratchet and the other portion incorporates a catch for the stud on the cycling cam carriage. The engagement of this stud prevents the mechanism from going into cycle. Center Post32 The cente

16、r post performs the function of supporting and aids in the separation of the records. Tone Arm Return Lever and Latch53B The tone-arm return lever, together with the latch, locks and stabilizes the tone arm in its outermost position. It also gives the necessary inward motion to the tone arm. Cycling

17、 Cam Carriage50A This carriage provides a movable support for the cycling cam. Tone Arm Director Lever71 The roller on one end of this lever follows a channel in the cycling cam and thereby pulls on the cable directing the vertical and outward motion of the tone arm. Locating Lever12 The sloped port

18、ion of the lever forms a stop for the stud on the tone arm return lever thereby determining the landing position of the pickup. Record Push Cam Gear Assembly5, 7 Provides a means of coupling the push cam to the rack lever. 118 RATCHET LEVER 63 TONE ARM ff , RETURN LEVER Figure 2 CYCLING CAM CARRIAGE

19、 50A CYCLE CAM 59 Record SupportI A, B, C. D Provides a support for the edge of the records and a mounting for the record push cam. Rack Lever10 One end of the lever follows the eccentric elevaied portion of the cycling cam causing the lever to move in and out from the center of the mechanism. The t

20、eeth on the rack lever en gage the teeth in the record push cam gear producing a rotary motion necessary to push the record off the step in the center post. Record Push Cam4 The oval shaped cam located in the record support, rotaies during change cycle. This cam engages and pushes the rec ord from t

21、he step in the center post. 收音机爱 好者资料库 RadioFans.CN MANUAL OF 1949 MOST-OFTEN-NEEDED RADIO DIAGRAMS ADJUSTMENTS Tone arm (out of cycle) height adjustment 1. Rotate the turntable until the change cycle is completed. 2. Move the tone arm to a position off the edge of the rec ord and allow it to rest f

22、reely in air; 3. Bend portion of the tone arm bracket so that the sapphire is 3/16 inches above the flat surface of the motorboard. i (Figure 3.) Tone arm height adjustment while in change cycle 1. Press the reject button and rotate the turntable- by hand until the pickup has raised, to the maximum

23、height in the change cycle. 2. Turn the adjustment screw A until the sapphire is 1% inches above the turntable. This adjustment will permit the pickup to land and play one record placed on the turntable. At the same time it prevents the tone arm from touching the record resting on the centerpost whi

24、le the mechanism is going through cycle. (If this height cannot be reached by the adjustment screw, take up on the cotter pin.) (Figures 4 and 5.) Pickup landing adjustment 1. Slide the record support as required for playing 10*inch records. 2. Place a ten-inch record on the turntable and rotate the

25、 turntable by hand until the sapphire is just ready to land. Loosen set screws B (Figure 6). 3. Hold the trip lever to keep it from moving while the pickup is moved to the start of the record. 4. Tighten the black screw B and allow the mechanism to run through cycle automatically. If landing is corr

26、ect, tighten copper plated screw B. (Figure 6.) (Note) No separate 12-inch landing adjustment is neces sary. Record push cam and gear assembly adjustment 1. Have the mechanism out of cycle. 2. With the push cam in place and the record support in the 10-inch position, assemble and engage the teeth of

27、 the push cam gear with the rack lever so the eye in the lever is approximately in line with the centerpost as shown in drawing. (Figure 7.) 3. Set the push cam parallel to the front edge of the rec ord support, make certain the thin edge of the cam is on the left side, viewed from the front or cent

28、erpost side of the support. (Figure 8.) Removing the turntable 1. Loosen the two screws mounting the centerpost. (Fig ure 10.) 2. The centerpost, turntable and thrust bearing can now be easily lifted out. Replacing the turntable 1. Slip the turntable over the lower end of the centerpost until it com

29、es against the stop or ears. (Figure 9.) 2. Place the thrust bearing and washers on the bottom end of the centerpost and place the centerpost and turntable in position as shown. (Figure 9.) a 3. Turn the spindle so the step in the centerpost is away ) from the record support. (Figure 11.) 4. Tighten

30、 the two mounting screws. (Figure 10.) Turntable centering If for any reason the sub-assembly had been removed from the motorboard it is necessary to re-center the turntable. 1. Loosen the three sub-assembly mounting bolts. (Fiaure 12.) 2. Place the turntable in place with the center post extend ing

31、 down through the mounting as shown. (It is not nec essary to have the thrust bearing in place for this opera tion.) (Figure 9.) 3. Center the turntable in respect to the recess in the motor- board by shifting the position of the sub-assembly slightly. (Figure 11.) 4. Tighten the nut on the end of t

32、he square head mounting bolt. (Figure 12.) 5. Remove the turntable and tighten the other two mount ing bolts. (Figure 12.) RP-178 SERIES Figure 3 Figure 4 Figure 5 Figure 6 viewed from CENTERPOST Figure 8 Figure 7 Figure 9 Figure 10 H . Sue ASSEMBLY CENTER TURNTABLE iN RESPCCT TO MOTORBOARO RECESS F

33、igure 12 Figure 11 113 收音机爱 好者资料库 RadioFans.CN Automatic Cycle Operator MANUAL OF 1949 MOST-OFTEN NEEDED RADIO DIAGRAMS RP178 SERIES CYCLE OF OPERATION Explanation Lift and slide tfce record support to 10 or 12 inch po sition as desired 10 LANDING) . SLIDE AND ? STUD DETERMINE 1. Record support lock

34、s in position and at the same time the record push cam and gear rotates and assumes a position as required for 10- or 12-inch records. Place the stack of records over the center post 1. The lower record of the stack is sitting on the step in the cen terpost, and the edge is resting on the record sup

35、port. Push reject button 1. The end of the reject button extending through the motorboard contacts and moves ratchet lever. riage. This allows the tension spring lo pull the cycling cam against the Totaling knurled roller and slart cycle. Tone arm rises 1. As the cycling cam rotates the small roller

36、 on the tone arm and moves out director lever follows the channel in the cam and in so doing pulls on the cable connected to the tone arm. 2. The hole in the motorboard provides a guide for the tone arm cable. It is so placed as to allow the cable to pull at an angle slightly off 90 degrees thus giv

37、ing the necessary rising and outward motion of the tone arm. 3. The trip lever which is rigidly connected to the tone arm through the tone arm pivot shaft is moved out with the tone - TONE ARM LiFT-1 DIRECTOR LEVER TONE ARM RETURN LEVt.R and latch -STUD ON TRIP LEVER TRIP LEVER The tone arm return l

38、ever has moved out slightly ahead of the trip lever. The tone arm return lever together with the small latch assumes such a posilion so as to engage the stud on the trip lever and stabilize the tone arm in its outermost posi- The record push cam together with the step in the centerpost sepa rates th

39、e lower record of the stack allowing it to drop to the turntable 114 1. While the cycling cam is continuing to rotate, the rack lever is being pushed outward by the small eccenlric elevated cam, with which it is engaged. 2. The teeth in the rack lever being engaged with record push cam gear, convert

40、s the sliding action oi the rack lever into a rotary motion. 3. The rotary motion of the record push cam pushes the record off the step in the centerpost. SPRING CYCLING CAM MANUAL OF 1949 MOST-OFTEN-NEEDED RADIO DIAGRAMS Tone arm moves In and lands on record CYCLE OF OPERATION Explanation 1. As the

41、 cycling cam is returning to normal position, the tone arm director lever is gradually allowing a slack in the tone arm cable. 2. While the tone arm director lever is gradually allowing slack in cable, the tone aim return lever is tending to retain the tension on the cable by returning the tone arm

42、to the landing position. 3. The distance the tone arm return lever travels, while moving the pickup in for landing, is determined by the contact between the tone arm locating lever and the stud on the tone arm return leveT. 4. After the tone arm return lever has moved the tone arm to the landing pos

43、ition the tone arm director lever continues to move and allow enough slack in the cable so the pickup can sit down on the start of* the record. Sapphire moves into record groove. Record begins to play The record plays RP-178 SERIES TONE ARM RETURN LEVER .yAMD LATCH 1. As the sapphire moves into the

44、playing groove, the cycling cam becomes disengaged from the rotating knurled roller as the roller falls into the step in the cam. 2. The change cycle is completed as the stud on the cycling cam carriage becomes engaged with the ratchet lever. This en gagement prevents the cycling cam from contacting

45、 the knurled roller, starting a new cycle. 1. After the playing of the record, the pickup moves into the SPBlNa eccentric groove. 2. The movement of the pickup in the eccentric groove causes the trip pawl to engage the ratchet lever starting a new cycle. (The mechanism plays one side of each record

46、in the stack then repeats the playing of the last record until the pickup is manually placed on the rest or the power removed from the mechanism.) /5TU0 ON cycling cam REPLACEMENT OF SAPPHIRE Caution: Never bend the sapphire support wire. Extreme care should be used when loosening the sapphire mount

47、ing nut so that the twisting motion does not break the crystal. Remove the two screws holding the sapphire guard in place and remove guard. Remove the small nut and washer on the threaded shaft of the sapphire holder and gently push the shaft through the hole in the armature shaft until the sapphire

48、 holder assembly comes free. Do not use force as the crystal may be broken. Insert threaded shaft of replacement sapphire holder through armature shaft and replace the washer and nut. Make sure that the sapphire is in the correct position. Take hold at the lower end of the shaft with a pair of plier

49、s while tightening the nut. being very careful so as not to strip the threads or break the crystal. Replace the sapphire guard, positioning it by means of the oversize screw slots. Make certain that the sapphire and its supporting wire are centered in the guard. Tighten the guard screws. Before using, check to see that the sapphire projects far enough (approx. .020) beyond the guard so that the guard will n