Since the Amphion system utilizes pneumatic switching for the 'Gate Box' instead of the more common 'sliding valves' or mechanical linkage, testing the device (see Pg 21 of the manual) is as simple a disconnecting the signal tube that controls the pouch inside of the box. Opening the signal tube should turn off the vacuum to the upper section. As also seen on Pg 21, the Gate Box and Reroll Valve (in the Air Motor Governor) are controlled by the 'Vent Block', which gets its signal from the valve in the transmission (see Pg 17, 'Transmission Lever Valve'.)

So as far as adjusting linkage, the only adjustment, or 'setting' in the Play/Reroll line that's important is insuring that the valve in the transmission does open and close 100%. The actual cut-out and fast rewind operations are handled pneumatically.

First, test the operation of the Gate Box. While pumping in the Play mode, disconnect the signal tube (small tube) on the Gate Box. The music should stop playing. If it does not, the pouch (or diaphragm) inside the box may be badly worn or damaged. If it does stop, the box is good. Reconnect the signal tube.

Next, test the Vent Block. As before, in Play, and pumping, disconnect the signal tube labeled 'Connection to Diaphragm from Transmission Valve'. The music should stop playing and the tempo of the air motor should increase significantly. If it does not, I would suspect the Valve in the Vent Block. The exhaust face of the valve may be badly dried out and leaking. Thus reducing the amount of atmosphere that gets emitted into the gate box and reroll diaphragms, and allowing the music to play backwards during rewind (at a slightly slower tempo than normal 'rewind' - which is fairly fast).

Next, test the air-tightness and air-flow through the tube that was connected to the Vent Block. This will test the condition of the transmission lever valve. With the unit in Play mode, (no pumping required), suck on the signal tube by mouth. No air should pass. If some does, there is a leak in either the tubing or the lever valve. Examine the valve surface for any signs of cracking. Move the unit into Reroll, and suck again. You should have substantial air flow. If you do not, the signal line might be pinched somewhere between the transmission and the vent block.