(4)
During normal testing procedures, the action of the GO switch, in conjunction with a flip-flop circuit, triggers a dual binary counter to provide consecutive test number data. This data is routed to the address inputs of two programmable read-only memories (PROM). The PROM outputs (binary form) representing the particular test number, is used to control a major portion of the BITE circuitry. The PROM outputs control test timing, provide tolerance and polarity information to the analog comparator, determines proper BITE stimuli for the cards being tested, pass appropriate read signal from the multiplexer to the comparator, and supply essential test number data to activate the front panel seven-segment digital display. A 14 stage counter and two, four-bit comparators are combined to form a clock circuit. The output of these combined circuits is one of five available test times. The selected read outputs, tolerance and polarity signals are applied to the comparator to produce a single output. This output and the selected timing signal are applied to several logic gates to determine either a pass or fail logic signal: A pass signal activates the PASS indicator; a FAIL signal activates the FAIL indicators.
(5)
Yaw Damper Coupler BITE Tests (Fig. 2)
NOTE: The following test descriptions are typical and may not represent the latest test procedures due to design improvements.
(a)
Unless otherwise noted, the following conditions are assumed for each test: 1) Yaw damper is engaged. 2) Hydraulics are on.
(b)
Test 1 - Rate Gyro Filter 1
1) GO is pressed. A stimulus is applied to the rate gyro input at 1 which drives the valve amplifier. Rudder position is read at 6 Test time is approximately 1 second.
(c)
Test 2 - Engage Null
1) GO is pressed. The stimulus at input 1 is removed and the valve amplifier output is read at 3. Test time is approximately 5 seconds.
(d)
Test 3 - Rate to Rudder (Displacement)
1) GO is pressed. A stimulus is applied to input 3 at the valve amplifier which drives the rudder. Rudder position feedback is read at 4. Test time is approximately 1 second/
(e)
Test 4 - Rate to Rudder (Integral)
1) GO is pressed. A stimulus is applied to input 3 at the valve amplifier which drives the rudder. Rudder position feedback is integrated and read at 1. Test time is approximately 45 seconds.
(f)
Test 5 - Trim Meter
1) Go is pressed. The stimulus at input 3 is removed and the rudder position feedback signal to trim meter amplifier is read at 5. Test time is approximately 8 seconds.
(g)
Test 6 - Disengage Synchronization
1) The yaw damper is disengaged, hydraulics are turned off and GO is pressed. A stimulus is applied to input 3 at the valve amplifier. The valve amplifier output is synchronized and the integrator output read at 1. Test time is approximately 5 seconds.
(h)
Test 7 - Rate Gyro 1) The yaw damper is disengaged, hydraulics are turned off, and GO is pressed. The stimulus at input 3
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22-11-00 Page 78 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. Oct 20/85
and the rate gyro is torqued. The rate gyro demodulator output is read at 2. Test time is approximately 1 second. Torquing stimulus is removed from the rate gyro at the end of the test.
2) The BITE switch is returned to OFF at the end of the tests. Hydraulics are applied and the yaw damper coupler is engaged for normal operation.
(6) Yaw Damper Coupler (P/N 4030952-906) BITE Tests (Fig. 2.)
NOTE: The following test descriptions are typical and may not represent the latest test procedures due to design improvements.
(a)
Unless otherwise noted, the following conditions are assumed for each test: 1) Yaw Damper is engaged. 2) Hydraulics are on.
(b)
Test 1 - Rate Gyro Filter 1
1) GO is pressed. A stimulus is applied to the rate gyro input at 1 which drives the valve amplifier. Rudder position is read at 5. Test time is approximately 1 second.
(c)
Test 2 - Engage Null
1) GO is pressed. The stimulus at input 1 is removed and the valve amplifier output is read at 3. Test time is approximately 5 seconds.
(d)
Test 3 - Rate to Rudder (Displacement)
1) GO is pressed. A stimulus is applied to input 3 at the valve amplifier which drives the rudder. Rudder position feed back is read at 4. Test time is approximately 1 second.
(e)
Test 4 - Rate to Rudder (Integral)
1) GO is pressed. A stimulus is applied to input 3 at the valve amplifier which drives the rudder. Rudder position feedback is integrated and read at 1. Test time is approximately 40 seconds. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737 AMM 飞机维护手册 AUTO FLIGHT 自动飞行 1(31)
