Assembling the steel ribbon for speed change.
Part No. CBE 771
This steel ribbon is fragile and must be assembled with great care. It is .003 inches thick. It can only be assembled in one orientation if correct speed change positions are to be achieved.
The above photo shows the steel ribbon, cam and drum being installed as a 3 part assembly. Note the position of the ribbon splice coupler, the cam relative to the idler bracket, and the drum. In this orientation the three pieces can carefully be fitted onto and into their appropriate mating parts.....but together, simultaneously.
If "one" attempts to first install the cam or the drum and then later fit the steel ribbon, "one" will find that the ribbon has absolutely no stretch to it. It wraps around corners and wheels but it won't stretch lengthwise. So we might be forgiven if, in the attempt to fit this assembly, we would wish to treat the ribbon as one might an elastic belt. Unfortunately, it can not work that way. Even worse, if "one" were determined to stretch the belt over the drive teeth on the cam when both the cam and drum are fitted into their respective mating parts, "one" could very well destroy the ribbon by tearing it in half. There are no 'oem' replacements for this part number. Proceed with great care for this portion of the assembly.
Above image: with 16 rpm cam position over the cam follower of the idler bracket and ready to push downward home. A spot of grease in the area where the ribbon engages teeth of the cam will help to keep wear to a minimum. Grease is also used over the large pin that pivots the cam and within the nylon bushing which houses the speed change drum. for this application I choose a high pressure grease such as is suitable for automotive wheel bearings.
At a latter stage of assembly the elevation adjustment for the idler wheel relative to the capstan is adjusted at the idler bracket as noted in the above photo.
above photo: with the drum rotated to its far right stop (in this view), with ribbon assembled to the drum by its single screw, and with the cam orientated over the idler bracket to engage the 16 rpm speed. Note position of the splice joint, (It must be 'near side' to the front of the TT. ) both the cam, ribbon and drum are slowly fitted over cam shaft and into drum bore simultaneously as a 3 part assembly. Then one must remember to install the two detent balls of the speed selector control. Note that all parts have been cleaned and lubed where appropriate.
After success at this end, you may next assemble the speed selector knob and eddy/fine pitch adjuster on the upper side of the turntable.
Switch Lever
Above photo: With Switch level installed. (part no: CBE 770)
The switch lever multi-tasks. It activates the on/off switch.....and it carries a cam follower (roller) that positions the idler wheel against the drive capstan.
It functions like this; turn the speed change/on/off knob on the top side of the tt and you rotate the drum beneath the knob. The steel ribbon, fastened securely to the drum drives/rotates the cam at its opposite end into position relative to the speed or off position that you selected. But the cam operates in two axes. It positions the idler wheel against the capstan (horizontal axis) and it also moves the idler wheel bracket in the vertical axis to match elevation of the 4 different capstan diameters.
In the image above, note the adjuster lever on top of the switch lever and the two machine screws securing it. Both screws lock the lever. The screw on the right locks and is pivot to the adjuster, the screw on the left when loosened will allow you to adjust the cam follower (roller) for position against the cam surface. Move it with your fingers. Adjust for optimum contact between idler wheel and capstan, then tighten both machine screws.
A light film of bearing grease is applied to the cam surface, within the cam follower and on the switch lever pivot shaft prior to assembly. The switch lever is retained by a phenolic washer and e-clip.