Your Tempo problem with the Ampico A is that the celluloid plate inside
the Tempo regulator has cracked and needs replacing.  The regulator is
located in the right side of the drawer in the very back.  To take it
out you need to drop the drawer.  This can be done without having to
remove the ca. 100 tracker bar hoses.

I do this by putting a pillow or bed spread on a small table or bench
and push it under the pull out drawer.  The pad should not be tight
against the bottom of the drawer.  You want it to drop down far enough
to get to the back of the drawer.  While holding one side of the drawer
up I then remove one of the guide roller units located under the keybed
and that side can be gently lowered onto the padded table.

The opposite end is removed by shifting the drawer to the side so the
guide rail slips out of the rollers.  This gives you ample room to remove
the regulator.  You will need to remove the tracking and play/rewind
pneumatics to pull the regulator.

I bought brass replacement Tempo plates some time ago from Player Piano
Co. but I don't know if they still have them.  Someone else may know.

Pete Knobloch
Tempe, Arizona