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

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1、MANUAL OF 1950 MOST-OFTEN-NEEDED RADIO DIAGRAMS The material on this changer which is used in many Philco combination models begins on this page and continues through page 118. This material is reproduced through the courtesy of the Philco Corporation. Madd 7K-20 Power for the motor is obtained thro

2、ugh the on-off switch mounted on the bridge assembly. This switch is operated manually by the control button with positions OFF-MAN-AUT-REJ. This button is located to the left of the record-shelf assembly, on the top of the Record Changer. . _ The Record Changer has three speeds, controlled by the S

3、peed Selector located to the right of the record-shelf assembly. The positions of the Speed Selector are STD PLAY- 45 -LONG PLAY. These speed changes are brought about by the shift lever, which changes the positions of the idler wheel and pulley with respect to the motor shaft. . , , . . , The chang

4、er mechanism of the Record Changer is brought into action when a small retractable gear segment, mounted on the cam gear, is released and engages the hub gear of the turntable shaft, causing the cam gear to be driven. X de a record is playing, the retractable gear segment is held in the retracted po

5、sition by the trip- plate retaining wall, which engages the roller of the gear segment. The segment is released either manually, by pushing the OFF-MAN-AUT-REJ control to REJ, or automatically, when the changer tone arm reverses direction as the needle follows the eccentric finish groove of a record

6、. For 45 r.p.m. automatic operation, an addi tional trip mechanism is brought into play. This trip mechanism is actuated by a trip stop, mounted on the trip receiver. When the needle of the tone arm enters the finish groove of a 45 r.p.m. record, the trip stop engages the trip lever, which releases

7、the hammer; this hammer strikes the trip plate, and pushes it aside. The gear segment is then released, as explained above, for either the standard or long-play operations. The tone arm of the Record Changer is operated by two link assemblies attached 收音机爱 好者资料库 RadioFans.CN SCREW B MANUAL OF 1950 M

8、OST-OFTEN-NEEDED RADIO DIAGRAMS TtUdel Mt-20 ADJUSTMENTS INDEXING OR SET-DOWN 7“ Record Set a 7 record on the turntable, push the OFF-MAN-AUT-REJ control to REJ, and rotate the turntable by hand approximately 4y2 turns. The tone-arm needle 76-5249 SELECTOR HINGE S6-7494 FEELER SPRING 56-7479 SELECTO

9、R HINGE SPRING 56-749S MAGNETIC INDEX STOP 76-S497 FIGURE 1. 7 INDEX ADJUSTMENT FIGURE 2. 10 INDEX ADJUSTMENT _ PUSH OFF BAR LOCKING SCREW NTCT then hold the tone arm steady, Ys in from the edge of the record, and set the trip arm so that the magnetic index stop, Part No. 76-5497, is in contact with

10、 the selector hinge (inside selector), Part No, 56-7494, as shown in figure 1. The index stop should engage the selector hinge by a minimum of l/8. Tighten the clamp screw, leaving y32 vertical play, or clearance, between the trip arm and the base plate. 10 Record Make the index adjustment for 7 rec

11、ords first. Check 10 indexing by the same method as that outlined above. With the needle point Yl above the record, and Ys in from the outside edge, the index stop should be in contact with the middle selector, Part No. 56-7478, as shown in figure 2. Ordinarily, the 10 index is satisfactory after th

12、e 7 index adjustment is made; if not, bend the selector slightly to the right or left, as required, for the proper set- down of the needle. 12 Record Adjust as given above for 10 records, except that the index stop should contact the outside selector, Part No. 56-7478. If the indexing is incorrect,

13、bend the selector hinge slightly to the right or left, as required, for proper set-down. TRIP ACTION 10 or 12 Standard or Long-Play Records With a 10 or 12 record on the turntable, the Speed Selector set to either STD PLAY or LONG PLAY, and the OFF-MAN-AUT-REJ control in AUT posi tion, place the ton

14、e arm in the finish, or eccentric, groove of the record. The trip finger, Part No. 56-7486, now rides over the ratchet of the trip plate, Part No. 76-5252, as shown in figure 3. The trip finger should ride at an angle of 25 to 30 with respect to the ratchet. To obtain the correct angle, adjust the s

15、crew on the trip receiver, Part No. 56-7491, as indicated in figure 3.- Make certain that the vertical center line of the trip finger coincides with the center line of the ratchet. To obtain this alignment, loosen screw “A” slightly, and screw B” completely, on the trip receiver, and swing the trip

16、receiver to the right or left, rotating about point A” until the trip finger is centered over the ratchet; then tighten the screws. When this adjustment is made, care should be taken to prevent the trip receiver from being pulled in toward the trip arm too far, as this will prevent the trip-arm stop

17、 from engaging the selector hinge by a minimum of Ys- A compromise between these two adjustments should be reached. The index adjustment will be affected when making the above adjustments. Remember that these three adjustments are interrelated, and that, when any one of them is made, the other two s

18、hould be rechecked. 7 45 R.P.M. Records Place a 7, 45 r.p.rn. record, with adaptor insert, on the turntable. Set the Speed Selector to 45, and the OFF-MAN-AUT-REJ control to AUT position. Set the tone arm on the portion of the record which contains the leadin grooves. The mechanism should trip when

19、the needle reaches a point approximately Ys from the last groove (which is concentric). If it trips before reaching this point, bend the trip finger, Part No. 56-7486, away from the trip-arm stop. If it fails to trip when this point is reached, bend in the opposite direction. The trip-arm stop shoul

20、d engage the trip by a minimum of %2” *n both the hori zontal and vertical planes, as shown in figure 3. This may be adjusted by loosening the trip locking screw, and sliding or raising the trip to the desired position. The horizontal force required to trip the changer and initiate the change cycle

21、should not exceed 2 grams at any turntable speed. TONE-ARM HEIGHT AND LIFT With the changer out of cycle, and the tone arm free, set the arm over the base plate. The needle point should be approximately %0 above the base plate, as shown in figure 4. To adjust the clearance, bend the protruding ear o

22、f the swivel post (bending the ear upward increases the clearance, downward decreases the clearance), as shown in figure 5. Now raise the tone arm to its maximum height, and place it 4 4 0 against the rest post. There should be a minimum of Ys clearance between the lower 11 收音机爱 好者资料库 RadioFans.CN N

23、EEDLE POINT 3/32 !MIN.) ABOVE BASEPLATE ADJUST EAR OF SHAFT AND SWIVEL BEND EAR TO OBTAIN CORRECT BASEPLATE CLEARANCE MANUAL OF 1950 MOST-OFTEN-NEEDED RADIO DIAGRAMS edge of the tone arm and the top of the rest-post hook. Adjust the ear on the swivel post until a mean is reached between the correct

24、rest-post clearance and base-plate clearance. TONE-ARM HORIZONTAL AND VERTICAL TIMING Before making the vertical and horizontal adjustments, make the tone-arm height and lift adjustments described above. FIGURE 4. BASE-PLATE-CLEARANCE ADJUSTMENT FIGURE 5. TONE-ARM HEIGHT AND LIFT ADJUSTMENT HORIZONT

25、AL ACTUATO VERTICAL TIMINGADJUST LOOP O LOWER LINK 56-7023 FIGURE 6. HORIZONTAL AND VERTICAL TIMING ADJUSTMENTS FIGURE 7. SPECIAL RECORD-SHELF GAUGE, SHOWN IN CORRECT POSITION MANUAL OF 19S0 MOST-OFTEN-NEEDED RADIO DIAGRAMS og) ADJUSTMENTS (Continued) 7/fadd 7K-2Q For the vertical timing, start with

26、 the changer out of cycle and the tone arm on the rest post, push the OFF-MAN-AUT-REJ control to REJ, and rotate the turntable approximately revolutions by hand. At this point, the lower eccentric portion of the cam-and-gear assembly, Part No. 76-3995-2, fully engages the lower (vertical) actuator (

27、the actuator with the cord), Part No. 76-5322. Adjust the wire loop of the lower link, Part No. 56-7023, figure 6, by squeezing or opening the loop so that the safety spring is expanded approximately Y32- With this adjustment, the ear of the tone-arm swivel post makes firm contact with the lower end

28、 of the cutout on the tone-arm pivot assembly. For the horizontal timing, start as given in the above paragraph. At the same point, 11/2 revolutions from, the start of the cycle, the upper eccentric portion of the cam gear fully engages the upper (horizontal) actuator. Part No. 76-5323. Adjust the w

29、ire loop of the upper link, Part No. 76-7023, with the short cord, figure 6, by squeezing or opening the loop so that the safety spring is expanded approximately yS2. With this adjustment, the tone arm should be snug against the rest post, but not so tight as to cause undue slapping as the arm retur

30、ns to the rest post during cycling. RECORD SHELF Set the record shelf to the 10 position, with the changer out of cycle. Loosen the two hex-head drive screws that hold the record-shelf assembly to the changer base plate just sufficiently to allow movement of the record-shelf stanchion. Place the Phi

31、lco record-shelf gauge, Part No. 45-1672, over the spindle and onto the record shelf, as shown in figure 7. Move the record-shelf assembly away from the spindle until the large, curved part of the gauge drops even with the record-shelf lips. Now push the record shelf and gauge lightly against the sp

32、indle, taking out all play toward the spindle; keep the lips of the record shelf in even contact with the edge of the gauge. Tighten the two hex-head screws. PUSH-OFF With the changer out of cycle, push the OFF-MAN-AUT-REJ control to REJ, and rotate the turntable 2 revolutions by hand. At this point

33、, the push-off actuator, Part No. 56-4588, is in its most forward position, in contact with the roller on the cam gear. Loosen the push-off-bar locking screw (indicated in figure 3) slightly (just sufficiently to allow adjustment), and squeeze the push-off ears toward each other until the slide plat

34、e on the record shelf extends between Ye 4 and %2 beyond the lips of the shelf. Tighten the hex-head push-off-bar screw. NEEDLE PRESSURE Use the Philco gram scale, Part No. 45-9531. Calibrate the scale to zero by holding it upright for vertical measurement, and setting the pointer to the center line

35、 of the scale. The center is the 0” point, and each small division on either side of ”0” is equal to one gram. * After the scale has been calibrated to zero, hold the scale perpendicularly to the tone-arm head, and support the tone arm by placing the standard-play needle in the hole at the end of th

36、e gram-scale arm, as shown in figure 8. By lifting the gram scale carefully, raise the tone arm approximately l, and note the reading. Then lower the tone-arm, and note the reading. The average of these two readings is the needle pressure, which should be between 7 and 9 grams. The pressure is adjus

37、t able by bending the ear at the rear of the tone arm to which the tone-arm spring is anchored, as shown in figure 9. Bending the ear so as to stretch the spring decreases the needle pressure; bending so as to relax the spring increases the needle pressure. If the needle pressure is out of tolerance

38、, make the above adjustments gradually, and recheck after each change, as a small movement gives a rather large variation in needle pressure. When making this adjustment, be careful not to bend or distort the bracket. If this bracket is deformed, the needle pressure on the last record of a stack wil

39、l differ from the needle pressure on the first record. When the proper needle pressure is attained, the upper edge of the ear should be parallel to the rear, lower edge of the tone-arm shell. If the bracket was bent while adjusting the ear, gently pry down or push up the bracket (applying even press

40、ure on both sides) until the ear and tone-arm shell are in proper relationship. IIS 116 FIGURE 10. MEASURING HORIZONTAL FRICTION MANUAL OF 1950 MOST-OFTEN-NEEDED RADIO DIAGRAMS TKUel M-20 ADJUSTMENTS (Continued) VERTICAL FRICTION FIGURE 8. MEASURING VERTICAL FRICTION FIGURE 9. NEEDLE-PRESSURE ADJUST

41、MENT To measure the vertical friction, take two gram-scale readings as explained above under NEEDLE PRESSURE. One-half of the difference between the two readings is the vertical friction, which should not exceed 1.5 grams. NEEDLE PRESSURE SPRING BEND EAR OF BRACKET 56-7402 MANUAL OF 1950 MOST-OFTEN-

42、NEEDED RADIO DIAGRAMS TKodel 7ft-20 HORIZONTAL FRICTION Calibrate the gram scale by laying it flat, face-up. Set the pointer to zero (center mark). Place a counterweight on top of the rear end of the tone arm, with the changer out of cycle; move the counterweight until the tone arm is balanced horiz

43、ontally, and the needle point clears the turntable. Hold the gram scale face-up, place its pointer against the side of the pickup, and slowly move the gram scale so as to push the tone-arm horizontally with the pointer, as shown in figure 10. Note the reading of the gram scale while moving the tone

44、arm throughout its entire travel (outside the trip range). At no time should the horizontal friction (the forc6 required to move die tone arm) exceed iy2 grams, nor be less than % of a gram. Note: Whenever any repairs or replacements are performed, all adjustments should be checked, and any necessar

45、y adjustments made. When making adjustments, check the lubrication at all points indicated in the LUBRICATION section, and lubricate where necessary, after cleaning off old and excess grease with a soft brush and carbon tetrachloride. UNEVEN TURNTABLE SPEED (WOWS) Uneven turntable speed may be cause

46、d by the following conditions. 1. Dirt under and around the idler-wheel assembly. 2. Idler-wheel spring loose or missing. 3. Flat spot on idler-wheel tire or on turntable. 4. Loose or worn pulley belt. 5. Oil or grease on idler-wheel tire, pulley, or drive shaft. !-T PHONO MOTOR POWER WIRING DIAGRAM

47、 OF MODEL M-20 117 MANUAL OF 1950 MOST-OFTEN-NEEDED RADIO DIAGRAMS Model 7H-20 LUBRICATION When the Record Changer is brought in for service, it should be well cleaned with a fine brush and carbon tetrachloride. Remove the needle guard and clean out accurau- lated dust with a fine brush. Remove all

48、dirt and old grease and oil. When applying new grease and oil, use it sparingly. Lubrication points are shown in figures 11 and 12 It may be necessary to remove some parts and assemblies in order to properly lubri cate them. For example, the cam gear and actuator levers should be removed to lubricate the cam-gear spindle and the actuator stud. GREASE GREASE OIL (4 SLIDER POINTS AND IDLER SUPPORT SHAFT) GREASE GREASE FIGURE 11. TOP VIEW, SHOWING LUBRICATION POINTS OIL GREASE GREASE GRAPHITE FIGURE 12. BOTTOM VIEW, SHOWING LUBRICATION POINTS GREASE GREASE