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1、MANUAL OF 1939 MOST POPULAR SERVICE DIAGRAMS Automatic Record Chairfcr GENERAL INFORMATION , . Before servicing the automatic record changer, inspect the assembly to see that all levers, parts, gears, springs, etc. are in good order and are correctly assembled. A biiid or jam in the mechanism can us
2、ually be relieved tbe turntable in the reverse direction. The changer can be conveniently rotated through its by pushing the index lever to “Reject and revolving the turntable by hand. Six turntable revolutions arrequired for one change cycle. ADJUSTMENTS A. Mein Lever.This lever is basically import
3、ant in that it interlinks the various individual mechanisms which control needle landing, tripping, record separation, etc. One adjust ment is provided for the main lever. Rotate the turntable until the changer is out-oLcycle; and adjust rubber bumper bracket (A) so that the roller clears the nose o
4、f the cam plate by 1/16 inch. B. Friction Outch.The motion of the tone arm toward the center of the record is transmitted to the trip pawl “22“ by the trm lever “7“ through a friction clutch “5. If the motion of the pickup is abruptly accelerated or becomes irregular due to swinging in the eccentric
5、 groove, the trip finger “7 moves the trip pawl “22“ into engagement with the pawl on the main gear, and the change cycle is started. Proper adjustment of the friction clutch “5“ occurs when movement of the tone arm causes positive movement of the trip pawl “22 without tendency of the clutch to slip
6、. The friction should be fust enough to prevent slippage, and is adjustable by means of screw “B. If adjustment is too tight, the needle will repeat grooves; if too loose, tripping will not occur at the end of the record. C. Pickup Uft Cable Screw.During the record change cycle, lever “16 is actuate
7、d by the main lever “15 so as to raise the tone arm clear of the record by means of the pickup lift cable. To adjust pickup for proper elevation, stop the changer inCycle at the point where pickup is raised to the maximum height above turntable plate, and has not moved outward; at this point adjust
8、locknuts “C to obtain 1 inch spacing between needle point and turntable top surface. D. at H. Needle Landing on Record. The relation of coupling between the tone arm vertical shaft and lever “20 determines the landing position of the needle on a 10 inch record. Position of eccentric stud “E governs
9、the landing of the needle on a 12 inch record; this, however, is dependent on the proper 10 inch adjustment. To adjust for needle landing, place 10 inch record on turn- table; push index lever to reject position and return to the 10 inch position; see that pickup locating lever “17 is tilted fully t
10、oward turntable; rotate mechanism through cycle until needle is just readp to land on the record; then see that pin “V on lever “14 is in contact with “Step T on lever “17.” The correct point of landing is 4-11/16 inches from the oearest side of the turntable spindle; loosen the two screws “D and ad
11、just horiiontal position of tone arm to proper dimension, being careful not to disturb levers “14 and “17. Leave approximatelv 1/32 inch end plav between hub of lever “20 and pickup base bearing, and tighten the blunt nose screw D ; run mechanism through several cycles as a check, then tighten cone
12、pointed screw “D. After adjusting for needle landing on a 10 inch record, place 12 inch record on turntable; push index lever to reject and return to 12 inch position; rotate mechanism through cycle until needle is just ready to land on the .ecord; the correct point of landing is 5-11/16 inches from
13、 nearest side of spindle. If the landing is incorrect, turn stud “E” until the eccentric end adjusts lever “14 to give correct needle landing. The eccentric end of the stud must always be toward the rear of the motor board, otherwise incorrect land ing may occur with 10 inch records. F- fk G. Record
14、 Separating Knife. The upper plate (knife) 25 on each of the record posts serves to separate the lower record from the stack and to support the remain ing records during the change cycle. It is essential that the spacing between the knife and the rotating record shelf “27” be accurately maintained.
15、The spacing for the 10 inch record is nominally .058 inch, and for the 12 inch record is .075 inch. ust rotete the knife to the point of minimum io adiust rotate t lao vertical separation from the record shelf and turn screw and locknut “F“ to give .055.061 inch separation. Screw “G“ must not be dep
16、ressed during this adjustment. After set ting screw “F“ adjust screw “G“ so that when its tip is depressed flush with top of record shelf, the vertical spacing between the knife, in its lowest rotational position, and the shelf, is .072.078 inch. H. RcGCMtl Suppmt Shelf.The record shelf revolves dur
17、ing the change cycle to allow the lower record to drop onto the turntable. 00th posts are rotated simultaneously by a gear and rack coupled to die main lever “15,“ and it is necessary that adjustments be such that the record is released from both shelves at the same instant. adjust, plftce a 12 inch
18、 record on the turntable, rotate mechanism into cycle to the point where tone arm is at maximum distance outward from turntable; lift record upward until it is in contact with both separating knives, then loosen .screws “H“ and shift record shelves so that the curved inner edges of the shelves are u
19、niformly spaced at least 1/16 inch from record edge. Tighten the blunt nose screw “H,“ run mechanism through cycle several times to check action, then tighten cone pointed screw “H“. If record shelves or knives are bent, or not perfectly horisontal, improper operation and jamming of mechimism will o
20、ccur. J. Tone Arm Rest Support fnot shown).When the changer is outofcycle, the front lower edge of the pickup head should be 5/16 inch above surface of motor board. This may be adjusted by bending the tone arm support bracket, which is associated with the tone arm mounting base, in the required dire
21、ction. K, Trip Pawl Stop Pin.The position of the trip pawl stop pin “K in relation to the main lever “15“ governs the point at which the roller enters the cam. By bending the pin support either toward or away from trip pawl bearing stud, the roller can be made to enter the cam later or earlier, resp
22、ectively. This adjustment should be made so that the roller definitely clears the cam outer guide as well as the nose of the cam plate. Lubrication.Petrolatum or petroleum jelly should be applied to cam, main gear, spindle pinion gear, and gears of record posts. MISCELLANEOUS SERVICE HINTS Incorrect
23、 adjustment of a particular mechanism of the changer is generally exhibited in a specific mode of improper operation. The following relations between effects on opera tion and the usual misadjustments will enable ready adjust ment in most cases. 1. For any irregularity of operation, the adjustment o
24、f the main lever “15“ should be checked first as in “A“. 2. Needle does not land properly on both 10 and 12 inch recordsMake complete adjustments “D“ and “E“. 3. Needle does not land properly on 12 inch record but correct on 10 inchEffect adjustment “E“. 4. Failure to trip at end of recordIncrease c
25、lutch “5“ friction by means of screw “B“. Also, see that levers “7“ and “12“ are free to move without touching each other. 5. Pickup strikes lower record of stack or drags across top record on turntableAdjust lift cable per adjustment “C“. 6? Needle does not track after landingFriction clutch “5“ ad
26、justment “B may be too tight; bind in tone arm vertical bearing; levers “7“ and “12“ fouled; or pickup output cable twisted. 7. Cycle commences before record is completeRecord is defective, or adjustment “B“ of friction clutch “5“ is too tight. 8. Wow in record reproductionRecord is defective; flexi
27、ble coupling between motor and changer mech anism not correctly assembled; or instrument is not being operated at normal room temperature (65 F). 9. Record knives strike edge of recordsRecords warped; record edges are rough; or knife adjustments “F“ and “G“ are incorrect. 10. Record not released pro
28、perlyAdjust record shelf as semblies in respect to shaft by means of adjustment 11. Needle lands in 10 inch position on 12 inch record or misses record when playing both types mixedIncrease tension of pickup locating lever spring “34“. COMPILED BY M. N. BEITMAN, SUPREME PUBLICATIONS 收音机爱 好者资料库 RadioFans.CN
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