> Wow, thanks for the reply and graphic.

Hi Mike, You are very welcome.

> Just FYI, mine don't have a motor.  It's all original.

By motor, I meant the pneumatic drive; we call this a "motor" also.

> Okay, thanks.  Mine has the 'older' style in the graphic.  Should
> I be worried about how much pressure the brake should have?
> I'm assuming that if I put too much, it will slow down the tempo
> or put too much tension on the roll itself.

You are correct.  There is another problem also; if the leaf spring
is to tight, it will tend to push the main lever out of the reroll
position.  That is why they went to the new design.  The sliding action
of the reroll lever against the brake wire in the new design did not
push the reroll lever out of position, and it was easier to adjust the
brake pressure by changing the place where the coil spring attaches to
the post.

It is not clear whether your spring is missing, or just bent out of the
way.  In either case, the new or replacement spring should press rather
lightly against the brake wire.  Start with the tension such that the
brake pad just presses lightly against the wheel.  Then increase the
tension only enough so that the upper half of the roll does not
wrinkle, or loop up when the tempo is suddenly slowed down, and the
roll plays at a constant speed.  But not enough so that the reroll
lever won't stay in the reroll position.  Sometimes it is necessary
to tighten the screw and fiber washer at the center of the reroll lever
a little, so that it will stay in "reroll" in spite of the spring.

This adjustment takes a lot of trial and error.  If the brake is
too loose, the roll won't move at an even tempo because there is
insufficient constant torque feedback to the complex pneumatic
pressure vs. flow control loop in the tempo valve and regulator system.
And on big rolls, the paper may not be wound up tight enough on the
take-up spool, so that "stack slippage" occurs within the paper on the
take-up spool, and the paper appears to stop momentarily even though
the drive continues to turn.

If too tight, the roll will jerk, slow down, or stall when playing
softly.

Test with a big, fat roll and a skinny one also.  The brake torque
imposes a much smaller tension on the paper and the motor, at the
beginning of a fat roll, that at the end of a skinny one.  An
adjustment which is compromise, working fairly well in both cases,
must be found.

Best regards,

Richard Vance