Ampico Function Switches
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Regulating the AMPICO A

Written by Bruce Clark (Retired)

Subject: Regulating Ampico A

First, I will say that the Ampico test roll gallops along so fast, that it is difficult to keep up with. By the time a test passes on the roll, and you try to take a reading, the roll is performing the next test. If you slow the roll down, or stop it, the air motor does not use air, and the readings are not correct.

Here is how I go about the job. Assuming that the crescendos work properly, and there are no leaks in the unit valves or other places, and all is working properly: You must have a very good and accurate vacuum gauge. Without it you can not make an accurate adjustment.

1. Cover the entire tracker bar with drafting tape, or a tape that does not stick severely.

2. Trick the take up spool so that it thinks there is a roll on it by applying more tape, either to cover the port on the take-up spool, or to trip the pallet valve (on uprights). Turn on the motor and set the control to the play position.

3. Set the Modify switch at medium, Ampico switch at on, Pedal on.

4. Set the tempo at 65. (I say this because the air motor uses a lot of air and will have some effect on the reading. There are other reasons, but I will not get into a lot of complex theories and confuse you at this point.)

5. Locate the expression units, and gently with your finger nudge the three intensity valve tops (2,4,& 6 ) so that they are locked in an up position.

6. Remove a hose going to a unit valve, on the bass end of the stack and connect a guage. Check the reading on the gauge. With the intensities tripped, and the modify switch set at Medium the gauge should read about 19 to 20 inches of water vacuum. To adjust this, slightly rotate the spill valve spring (the spring closest to the amplifier pneumatic) in very small turns right or left, to increase or decrease the reading. Check the treble end, and the reading should be the same.

7. Set the modify switch to Brilliant. The reading should increase to between 27" and 30". To adjust this, use the large screw in the top of the amplifier pneumatic, turning it in to lower the reading, and turning it out to raise the reading. (The small valve box that controls the amplifier pneumatic can be a source of problems. Make sure that it turns on and off properly)

8. When this is done, check it again, to be certain all is working well.

9. Next shut off the motor. This should cancel any intensities. Turn the motor back on, and disconnect the signal hose for the soft pedal. Taking readings at a unit valve in treble or bass. The reading should be about 7" of water vacuum or lower if possible. Low enough that the softest notes play very softly but do not drop out. Adjust this lower level by adjusting the springs on the Crescendo pneumatics.

10. If you have a test roll, you may now use it to test repetition, crescendos, soft, and loud pedals. Any notes that do not play or repeat softly on this test, may or may not have unit valve problems. Usually the problem can be traced to a dirty bleed, or leaky unit valve. Other times the problem can be in the piano action itself.

11. Tempo test. "Tempo 60" is six feet per minute, "Tempo 70" is seven feet per minute. If you do not have a test roll, mark an old roll in feet, and time it with the second hand of a clock or watch. Adjust accordingly, so that the marking on the tempo pointer is correct.

I hope that this will be helpful. If you have any problems, please feel free to contact me.

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Information Update 06/14/2005

These instructions are applicable to all model A Ampicos, with or without an air motor. If the piano has an air motor set the tempo at 65 first. Without an air motor, use the same instructions.

1. Place tape over tracker bar, covering every hole, and set lever at PLAY.
2. Set modify switch on Medium.
3. Remove hose 1-B and 1-T at both bass and treble Crescendo mechanisms.
4. Take reading by connecting a hose to the nipple of a bass unit valve from gauge, and a treble unit valve. Readings should be the same both for bass and treble. The reading you should have is 20" of vacuum. To adjust this, using thumb and forefinger, ROTATE Spring on pump (Service manual illustration 9 FRONT ASSEMBLY # 5) until gauge reads 20" Once this is reached, move modify switch to Brilliant. The reading should move to between 27" and 30" According to taste, and room size. 30" could be considered a bit too loud. But reading should not be below 27" or over 30" This is adjusted buy rotating the large screw on top of the Amplifier pneumatic on top of pump. #8 in illustration 9.

Check to see that the modify switch is working properly by moving from MEDIUM to BRILLIANT several times. If there is a problem, it is probably in the amplify control box, Illustration No. 10. The problem is in the valve stem #11 which does not always seat correctly, because in many cases it is solidly attached to the valve button. To remedy this, remove the valve button, cut off the valve stem #11 and re-attach it using a felt dot, or soft piece of leather between the valve stem and the valve button. This will allow the valve button to wobble a bit and it will seat correctly each time it is required. Be sure to compensate for the addition, by reducing the length of the valve stem so that it is not riding on the pouch cap, when the modify switch is set at MEDIUM.

If you are concerned about using SUBDUED, make the adjustment moving the leather nut #17 under the spring on the subdued pneumatic, either up or down, (Illustration 2 A in service manual) until reading is between 10" to 12" according to taste.

Once this is accomplished, replace the hoses 1 B and 1 T on the crescendo units, and set the first intensity, by rotating the screws on each crescendo unit. In Illustration 2. CRESCENDO in Service Manual. First remove hose #3 on the soft pedal pneumatic to allow the soft pedal to be on during the setting. (Illustration No. 6 in service manual) Rotate spring #31 Seek a reading of 7" or lower. Keep going as low as you can without very soft notes dropping out. Replace #3 hose on soft pedal pneumatic. Once this is accomplished the Ampico should be correctly adjusted and express perfectly. (providing everything in the expression mechanism is working properly and there are no leaks)

One good test for this is to use the roll: Rachmaninoff Prelude in C sharp minor. Using the gauge, modify switch set at brilliant and the specified tempo on the roll, the first notes of the prelude should move the gauge to between 27" and 30".

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Comments or Questions to: Bruce Clark

This page was last revised on February 9, 2013 by John A. Tuttle at Player-Care

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