My favorite record changer is the Collaro Conquest. Appearing in several different forms, it is one of the most useful record changers around. Standard features include:
The 4 photos show (in sequence) my Collaro Conquest at rest, feeling a 7" record, playing the 7" record, and feeling the absence of records at the end of the stack.
The pickup arm itself is used to feel the record size. During the change cycle, the pickup arm rises from the record and swings out over the restpost, clear of the record stack. It then does something a little different from what most other record changers do. Before the record drops, the arm rises up to the height of the unplayed stack, and moves toward the records on the spindle. If there are records on the spindle, the feeler bar on the left side of the pickup head strikes them, measuring very accurately the diameter of the largest record in the stack. This, of course, means that larger records must be placed before smaller records in the stack.
After the arm feels the size of the record, it returns to a position over the restpost, and the record drops. Then the arm lowers down below the records on the spindle, swings in over the starting groove of the record that dropped, and sets down on it. If the arm doesn't find a record when it feels for one, then it stays over the restpost when it swings out the second time, and the power shuts off as the arm sets on the post.
With very little work, I added the following features to my unit.
Autospeed is activated by starting my Collaro Conquest in 33, and then changing the speed control to 45 during the first change cycle. If you do not know that Autospeed is there, you will not even notice it unless you try to change speed after starting a record stack. During each change cycle, the brass feeler arm comes toward the spindle just after the arm rises from the record that finished playing. It contacts any record larger than 9" that is up on the spindle. If it contacts a record, and Autospeed is active, the speed will stay at 33 RPM. If it does not contact a record, the speed automatically changes to the current setting of the speed control. Autospeed never persists beyond one stack of records, unless the stack is stopped by hand. If this occurs, starting a change cycle with no records on the spindle will clear Autospeed.
My Collaro TSC-640/1019A Conquest at rest
Feeling the size of a 7" record
Setting the pickup down on the 7" record
Feeling the absence of a record for automatic shutoff
An older Collaro Conquest TC-340
Collaro Conquest spindle
Pickup arm scan is a novel mechanism developed by Collaro. It uses a unique method of indexing the arm setdown and activating automatic shutoff, which is done by using the pickup arm, and the actual diameters of the records themselves. Like the feeler arm on a Webcor 100, this is an arranged intermix. Because the unplayed stack is felt to find the record size, larger records must be placed before smaller ones in the stack. Unlike the index arm, the pickup arm itself does the feeling. This index can find out the actual diameter of the record, meaning that odd sized records will also play automatically, if they have lead-in and finishing grooves.
This mechanism shown in Fig. 1501-a (figure numbers are from a book I earlier wrote about record changers) uses a groove-track cam. There are very few parts in this index. A friction clutch mounted on the pickup arm shaft couples it to the arm control finger. It serves as the safety drive, preventing damage if someone grabs the arm during the change cycle, and is also used to remember the record size. The pin on the end of the arm control finger rides in the groove track on the cam. When the changer is out of cycle, the arm control finger moves in the wide portion of the groove track (Fig. 1501-a). The arm control spring (Fig. 1501-b) pushes down on the arm control finger, but an adjustment screw and locknut keeps it from touching the bottom of the track. This allows the pickup to track the record freely. An incline cam raises the pickup arm. The trip mechanism is the velocity type, detecting the speed-up of the pickup arm as it enters the finishing groove of the record.
When the change cycle starts, the incline cam raises the pickup arm. Then the groove track narrows and forces the arm control finger outward. This action swings the pickup arm out (Fig. 1502-a). When the pickup arm arrives over the rest post, the stop ear attached to the pickup arm shaft contacts the locator stud. This action stops the pickup arm over the rest post, while the friction clutch slips until the arm control finger has moved all of the way to the outside edge of the change cycle cam. This removes the size of the previous record from the friction clutch.
Now the incline cam moves the pickup arm raising lever to raise the pickup arm even higher, so the feeler bar on the left side of the pickup end of the arm is as high as the unplayed stack. The pin on the arm control finger then enters the test track. The test track moves the pickup arm toward the spindle, causing the pickup arm to scan for the presence of a record on the spindle. When the feeler bar contacts the edge of a record, it stops the pickup arm from swinging in any farther (Fig. 1502-b). The friction clutch slips and allows the arm control finger to continue to follow the test track. The exact radius of the record is now "remembered" by the friction clutch.
The arm control finger now enters the sloped track. This is designed so that the arm control spring makes the arm control finger follow the track as long as the arm meets no resistance. This causes the pickup arm to move away from the spindle and record. As soon as the arm is no longer touching it, the record is dropped by the spindle ejector, which pushes the bottom record sideways off of the ledge on the spindle. Outward motion of the pickup arm is necessary here so that the record can fall flat.
While the arm is swinging out again, the incline cam lowers it enough that it will miss the unplayed stack when it swings in again later. When the pickup arm arrives over the rest post again, the stop ear again contacts the locator stud. But this time, we don't want the friction clutch to slip. A slip would erase the record size that was just so carefully measured. The sloped wall of the track prevents this. When the stop ear contacts the locator stud, the pin on the arm control finger rides up and over the sloped wall of the track (against tension of the arm control spring) and onto the plateau part of the cam, as shown in Fig. 1502-c.
As the cam continues to rotate, the pin on the arm control finger drops into the setdown track at the other end of the plateau, This track swings the pickup arm inward, to stop over the lead-in groove of the record (Fig 1502-d). The final position of the arm depends on how much the friction clutch slipped while the arm control finger rode the test track. Thus, it depends on the exact size of the record. Now the incline cam lowers the pickup arm to the record. As the changer goes out of cycle, the pin on the arm control finger enters the wide part of the groove track, so the pickup can track the record.
This index can play records of any diameter from 12" to 6". Because the arm accurately measures the largest record on the stack, not just the bottom record, the largest record in the stack must be the one about to drop. Therefore, records must be arranged in the stack so that larger records are played before smaller records.
Collaro Conquest change cycle cam
Collaro Conquest change cycle with record
The same basic sequence of operations takes place in automatic shutoff. The setdown index parts bring about automatic shutoff. When there are no records on the spindle, the pickup arm swings in close to the spindle as the arm scans for record size. Because the arm doesn't contact a record, the friction clutch does not slip at the test track, and no record size is "remembered" by the position of the clutch.
Immediately after the last record drops, there are no records on the spindle. But the last record must be played too. Since the arm scans the unplayed stack before the record drops, the spindle does not become empty until after the size of the last record was scanned. The friction clutch then remembers the record size. Since the arm does not again check for size after the record drops, this delays the shutoff. Thus, the last record is allowed to play.
During the next change cycle, the pickup arm does not contact a record while the arm control finger follows the test track (Fig. 1503-a) to scan for record size. Then, when the arm control finger rides the sloped track, the stop ear does not contact the locator stud until after the arm control finger reaches the outside edge of the cam (Fig. 1503-b). This means that the arm control finger does not ride up the slope of the track, and it does not enter the plateau. Instead, it enters the shutoff track. Once the pickup arm has swung out after the scan, the shutoff track does not swing it in again, but keeps it over the rest post.
As the pin on the arm control finger follows the shutoff track, it pivots the shutoff lever. Normally, the shutoff lever misses the power latch lever as the change cycle cam rotates. But when the shutoff lever is pivoted (Fig. 1503-c), it strikes the power latch lever (Fig. 1503-d), releasing the power switch lever just as the change cycle ends. A spring turns the control knob to OFF and pulls the idler wheel away from the motor shaft.
When a new stack of records is to be played, the records are loaded, and the control knob is turned to START-REJECT. This latches the power switch lever on the power latch lever (engaging the idler wheel and turning on power), and starts the change cycle. When the arm control finger enters the test track to scan for record size, a record blocks the arm's motion, and the friction clutch slips. As a result, the pickup arm sets down on the record. The changer will now play the entire stack.
If the changer is accidentally started without records on the spindle, the arm will not be stopped by a record when the arm control finger follows the test track, and the changer will shut itself off again. This safety feature prevents the arm from setting on an empty turntable.
Collaro Conquest change cycle with no record
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