Attachment_10_Environmental_Test_Plan_for_GMFC_DCU250A.pdf

ATTACHMENT X: GUIDED MISSILE FLIGHT CONTROLLER

ENVIRONMENTAL TEST PLAN, PART 1, FOR REFERENCE PURPOSES ONLY

Engineering & Logistic Support for

ALCM Laboratory Test Programs

Environmental Test Plan

Guided Missile Flight Controller, DCU-250/A

(PN 232-11270-21)

For

OC-ALC/498th NSW/NWBAN

Attn: Brian Keenan 7330 Sentry Blvd

Tinker AFB, OK 73145-8901

Final

14 May 2012

TABLE OF CONTENTS

Section Page

I. ITEM DEFINITION

1.1 Physical

1.2 Theory of Operation

II. AGE SENSITIVITY ITEM ANALYSIS SUMMARY

III. TEST METHODS

3.1 Test Methods for Each ASIA Parameter

3.1.1 RF Filter Capacitors

3.1.2 Solid Tantalum Capacitors

3.1.3 Wet Tantalum Capacitors

3.1.4 Ceramic Capacitors

3.1.5 Metalized Paper-Plastic Capacitors

3.1.6 Diodes

3.1.7 Zener Diodes

3.1.8 EMI Filter Capacitors

3.1.9 ICs

3.1.10 Inductors

3.1.11 Relays

3.1.12 Transformers

3.1.13 Transistors

3.1.14 Circuit Board Substrate

3.1.15 Discrete Wire

3.1.16 Connectors

3.1.17 EMI Seal

3.2 A&S Parametric Test Methods and Environments for GMFC Assembly

3.2.1 Visual Inspection, External

3.2.2 Functional Tests

3.2.3 RF Filter Capacitor Tests

3.2.4 Solid Tantalum Capacitor Tests

3.2.5 Wet Tantalum Capacitor Leakage Current and Capacitance

3.2.6 Electrical Bond Between GMFC Housing and Covers, EMI Filter, J2, and J3 29

3.3 Test Methods Requiring Removal of GMFC Cover

3.3.1 Visual Inspection, Cover Removed

IV. TEST EQUIPMENT AND FACILITES REQUIREMENTS

V. AGING & SURVEILLANCE STORAGE ENVIRONMENTS

VI. A&S TEST REQUIREMENTS

6.1 Test Classifications

6.2 Test Types

6.2.1 Baseline “A” Tests

6.2.2 Interval “B” Tests

6.2.3 Comprehensive “C” Tests

6.3 Test Sequence

VII. MEASUREMENTS LIST

LIST OF TABLES

Tables Page

Table 1. GFMC Major Electronic Assemblies

Table 2. Recommended Parameters for GMFC Monitoring Table 3. Device Specifications for Wet Tantalum Capacitor Aging Concerns Table 4. Random Vibration Levels Table 5. Temperature Test Levels Table 6. Combined Environmental Test Levels Table 7. RF Filter Functions that can be Tested at External GMFC Connectors Table 8. AC Power Supply Solid Tantalum Capacitor Tests at GMFC Connector J2 Table 9. C11 & C12 Wet Tantalum Leakage Current and Capacitance Tests Table 10. AC Pwr Supply Wet Tantalum Leakage Current and Capacitance Tests Table 11. EMI/EMP Bond Tests Table 12. Equipment and Facilities Required for GMFC Testing Table 13. Recommended A&S Tests Table 14. A&S Sample GMFCs Test Schedule for the First 10 Test Cycles (10 years)

Table 15. Measurement List

LIST OF FIGURES

Figures Page

Figure 1: GMFC Physical Interface Figure 2: GMFC Electrical Interface Figure 3: Partial EMI Filter Equivalent Circuit Diagram

Figure 4: Partial AC Power Supply Equivalent Circuit Diagram Figure 5: Partial EMI Filter Schematic showing C1-C7 In-Circuit

Figure 6: Partial DC Power Supply Schematic showing Wet Tantalum Caps Figure 7: Partial EMI Filter Schematic showing FL1 and FL2 In-Circuit

Figure 8. Temperature Variances for MOB 1 and MOB 2 Figure 9. Humidity Variances for MOB 1 and MOB 2 Figure 10. Recommended Test Sequence and Total Number of Samples Per Test Cycle ...36

I. ITEM DEFINITION

1.1 Physical

The Guided Missile Flight Controller (GMFC) is defined on engineering drawing 232- 11270-21. The source for all GMFCs was The Boeing Company, CAGE 81205, more commonly referred to as Boeing.

1. The GMFC weighs 17.3 pounds and has physical dimensions that encompass approximately 8.7 inches in depth, 12.0 inches width and 7.9 inches in height.

2. Power requirements for the device include +28 Vdc and 115 Vac, 400 Hz input power. The GMFC provides +/- 15 Vdc output power to both the Flight Data Transmitter and Elevon Actuator Controller. The GMFC transforms the 115 Vac, 400 Hz input signal to a 10 Vrms, 400 Hz signal for output to the Inertial Navigation System and 8 Vrms, at both 400 Hz and 3908 Hz for output to the Flight Data Transmitter.

3. The GMFC includes eight electronic assemblies which are mounted in the cast aluminum housing. Connections within the flight controller are made by means of a wiring harness and circuit-card connectors. Top and bottom screw-mounted covers provide internal access to the unit. Electrical interface with other units of the air vehicle is provided by two multiple-pin connectors. A third multiple-pin connector provides test interface capability. Electromagnetic shielding is provided by EMI gaskets on top and bottom covers and all connector mounting cutouts.

Figures 1 and 2 show the physical and electrical interfaces between the GMFC and other ALCM components.

Figure 1: GMFC Physical Interface

GMFC

UmbilicalAircraft

Actuator Controller

INE

Flight Data Transmitter

Engine

Figure 2: GMFC Electrical Interface

Figure 2: GMFC Electrical Interface (continued)

The eight GMFC electronic assemblies, commonly referred to as Shop Replaceable Units (SRUs), are identified in Table 1. (Note that A3 is an integral part of the DC Power Supply A2 and is not a stand alone SRU).

Table 1. GFMC Major Electronic Assemblies

Separate ETPs have been developed for the major electronic assemblies identified in Table 1.

1.2 Theory of Operation

The GMFC provides for missile flight control along the path determined by the inertial navigation system. The GMFC responds to stimulus commands from both the inertial navigation system computer and the flight data transmitter. Input data is processed and analyzed by the GMFC which subsequently provides analog outputs to the engine throttle control and elevon actuator controller. In this manner, the GMFC controls both the speed of the missile and the pitch and roll, or flight attitude. Two power supply assemblies in the GMFC provide self serving operating voltages and operating voltages to both the flight data transmitter and the elevon actuator controller. In addition to the flight control circuitry, the GFMC contains circuits that provide built-in–test equipment (BITE) capabilities for the missile. This test capability augments ground test operations as well as pre-launch testing to check and verify operation of the flight control functions.

II. AGE SENSITIVITY ITEM ANALYSIS SUMMARY

The Age Sensitivity Item Analysis (ASIA) on the Air Launched Cruise Missile (ALCM) Guided Missile Flight Controller (GMFC) has concluded that the device is age sensitive and that its inclusion in the ALCM A&S program is appropriate. The details concerning

Major Assembly Designator Part Number

EMI Filter Assembly A1 232-11678-4

DC Power Supply A2 232-11677-5

BITE Circuit Card A4 232-11668-4

Roll Circuit Card A5 232-11670-5

Pitch Circuit Card A6 232-11671-5

Command Circuit Card A7 232-11669-7

Gyro Interface A8 232-11667-4

AC Power Supply A9 232-11676-5 all ASIA findings and recommendations are documented in the ALCM Guided Missile Flight Controller ASIA Report, dated 27 April 2012.

The GMFC ASIA concluded that in addition to various manufacturing defects and process optimization issues discovered during laboratory analysis, many components used in the GMFC have aging effects and conditions that alone, or in combination, could eventually cause the unit to fail. The aging effects include:

Metal migration leading to high leakage currents, increased equivalent series resistance, and/or open/short circuits in wet tantalum capacitors, polycarbonate capacitors, ceramic capacitors, RF filter capacitors, EMI filter capacitors, Zener diodes, and ICs.

Corrosion due to contamination, Fractured seals in wet tantalum capacitors, paper/plastic capacitors, RF filter capacitors, diodes, ICs, discrete wires, and connectors.

Thermal decomposition, stress, and/or fatigue leading to loss of continuity or leakage, open circuits, or change in characteristic values in wet and solid tantalum capacitors, ceramic capacitors, RF filter capacitors, transistors, inductors, transformers, relays and ICs.

Moisture ingress due to voids or delaminations in conformal coating or damaged interface seals at electrical connectors could lead to long term performance issues.

Embrittlement and cracking of the EMI seal could limit weapon system effectiveness under specified environmental conditions.

These mechanisms, coupled with other known aging mechanisms in this type hardware, have led to the identification of 34 critical parameters and 7 non-critical parameters for the GMFC. The delineation between critical and non-critical parameters can be found in the GMFC ASIA Report.

Table 2 summarizes the conclusions of the ASIA study and identifies the critical and non-critical aging mechanisms that should be considered for inclusion in the A&S program for this component as well as the SRUs associated with the various aging mechanisms.

Table 2. Recommended Parameters for GMFC Monitoring

Item #'s Identifier Name Aging Mechanism Failure Mode

Critical versus

Non-Critical

Associated

SRUs

1&2 Polycarbonate Capacitors Zinc Diffusion No known affect Non-Critical Roll CCA, Pitch CCA

Internal solder deficiency combined with thermal fatigue

Cracks in solder attachments Critical

Cracks in ceramic capacitor elements coupled with electro migration

Internal shorts in capacitor elements Critical

Fractured glass seals leading to long term corrosion of terminal connections

Loss of terminal conductivity Critical

Thermal Fatigue due to thin MnO2

Cracks Critical

Bad Seal, Contamination Shorts or Cracks Critical Metal migration High leakage current Critical Metal migration Electrical short across capacitor Critical

Metallic corrosion due to chlorine contamination

Loss of continuity or leakage of capacitor Critical

Thermal decomposition of gel Change in capacitance Critical Thermal Fatigue Cracks in material and lead attachments Critical

Copper and Silver diffusion into bulk solder joint

Cracks in lead attachments

Critical

65-81 Hermetically Sealed Metalized, Paper-Plastic Capacitors

Fractured glass seals leading to long term corrosion of aluminum capacitor plates

Loss of terminal conductivity

Critical

EMI Filter, BITE CCA, Roll CCA, Pitch CCA, Gyro CCA, AC Power Supply

82-104 Diodes Cracks in glass body Contamination of diode junction or corrosion in lead attachments

Critical

DC Power Supply, BITE CCA, Roll CCA, Pitch CCA, Command CCA, Gyro CCA, AC Power Supply

Electro migration of lead to the die stacks

Increase in leakage current Critical

Cracks in glass body Sped up electro migration or other contamination Critical

110 EMI Filter Capacitors Cracks in ceramic capacitor elements coupled with electro migration

Internal shorts in capacitor elements Critical EMI Filter

111-113 IC, Hybrid Micro Dislodged gold particles leftover from assembly

Vibration induced shorts

Critical Roll CCA, Pitch CCA, Command CCA

Silicon nodules Increased local resistance in part Critical

Wire bond alignment coupled with vibration

Internal component short Critical

Thermal fatigue Cracks in various elements of IC Critical

Corrosion of SOG passivation due to contamination

Switching failures and other silicon junction failures Critical

DC Power Supply, BITE CCA

EMI Filter

AC power Supply

EMI Filter, AC Power Supply, DC Power Supply

BITE CCA,

Roll CCA, Pitch CCA, Command CCA, Gyro CCA, AC Power Supply

DC Power Supply, BITE CCA, AC Power Supply

IC, Analog Purpose

7-11

12-64

105-109

Wet Tantalum Capacitors

Solid Tantalum Capacitors

Ceramic Capacitors

RF Filter Capacitors

Diodes, Zener

Guided Missile Flight Controller

121 & 122

Table 2. Recommended Parameters for GMFC Monitoring (cont)

Critical versus

Non-Critical

Associated

SRUs

123-128 147-150

IC, Op amp Diffusion of phosphorous die contamination

Charge inversion and bond pad corrosion

Critical

BITE CCA,

Roll CCA, Pitch CCA, Command CCA, Gyro CCA, AC Power Supply

129 & 130 IC, Optical Isolator LED aging Insufficient emission for operation Critical

DC Power Supply, BITE CCA

Ionic contamination leading to corrosion

Electrical leakage between signals Non-Critical

Dislodged tungsten particles leftover from assembly

Vibration induced shorts Critical

156-161 Inductors Breakdown of insulation and thermal stress

Increase in series resistance or shorts in inductor coils

Critical EMI Filter, DC Power Supply, AC Power Supply

Contact wear, contamination in contacts, or copper diffusion on contacts

High resistance contact path or open path

Critical

Breakdown of coil insulation or thermal stress of coil

Unacceptable pull-in or fall out voltage, nonoperational relay Critical

168-220 Resistors Deterioration of carbon composition resistors

Change in resistance value Non-Critical All SRUs

378-383 Transformers Breakdown of insulation and thermal stress

Increase in series resistance or shorts in inductor coils

Critical DC Power Supply, AC Power Supply

384-403 Transistors Thermal fatigue associated with the Au-Si eutectic die attachments

Thermal runaway

Critical

DC Power Supply, BITE CCA, Roll CCA, Pitch CCA, Command CCA, Gyro CCA, AC Power Supply

Multiple Circuit Board Substrate Fatigue Cracks in conductive paths Critical All SRUs

Multiple Discrete Wire Fatigue Cracks in insulation, chaffing, or wire breaks Critical GMFC

Moisture ingress Resistive path between pins Critical

Corrosion Resistive path between pins, open circuit Critical

N/A Housing Corrosion Fracture of mounting lugs Non-Critical GMFC

N/A EMI Seal Embrittlement and cracking Loss of EMI protection Critical GMFC

Moisture ingress Resistive paths increased Non-Critical Corrosion Changes in inductance/capacitance at connections

Non-Critical

Inadequate application Structural instability of piece parts Non-Critical

BITE CCA,

Roll CCA, Pitch CCA, Command CCA, Gyro CCA, AC Power Supply

EMI Filter, BITE CCA, Roll CCA, Pitch CCA, Command CCA, Gyro CCA, AC Power Supply

GMFC and all SRUs

All SRUs

Guided Missile Flight Controller

Relays

Connectors

Mutiple Conformal Coating

162-167

N/A

All ICs IC, Digital/Analog

Aging & Surveillance testing on the GMFC is required to provide the data necessary for analysis and life predictions relative to the aging mechanisms identified in Table 2. The critical aging parameters identified can be grouped into categories based on aging mechanism, which is given below. Methods of testing each of these aging mechanisms are discussed in Section III.

1. Twelve (12) critical parameters are associated with thermal fatigue and breakdown.

2. Five (5) critical parameters are associated with possible metal migration and diffusion.

3. Three (3) critical parameters are associated with manufacturing processes that were less than optimal

4. Four (4) critical parameters are associated with corrosion due to contamination (these are driven in part due to less than optimal manufacturing processes).

5. Five (5) critical parameters are associated with cracks and fractured seals (these are driven in part due to less than optimal manufacturing processes).

6. One (1) critical parameter is associated with possible pad de-lamination (this is driven in part due to less than optimal manufacturing process).

7. One (1) critical parameter is associated with silicon nodule accumulation, a byproduct of the technology used in manufacturing the devices.

8. Three (3) critical parameters are associated with normal wear and tear expected of these type devices and include; relay contact wear, connector moisture ingress, and wear out of an optical isolator LED.

III. TEST METHODS

This report section describes test methods recommended for the A&S program for the GMFC. Program constraints limit ALCM A&S testing to non-destructive test types.

Therefore only test methods and test environments that are non-destructive in nature are fully documented for use in the development of the Test Requirements Documents. In Section 3.1, test methods are described which are suitable for characterizing the individual ASIA parameters noted in Section II. In Section 3.2, these test methods are combined into more specific A&S test methods that will be used as the basis for the development of the Test Requirements Document (TRD) in those cases where non-destructive tests can be implemented.

3.1 Test Methods for Each ASIA Parameter

The following paragraphs discuss methods of testing for each of the critical aging mechanisms identified in the ASIA and noted in the table of Section II. Where applicable, alternative methods of testing are discussed, and recommendations are made.

Critical parameters that cannot be appropriately tested and monitored at the GMFC assembly level will be carried over to the SRU level tests in accordance with ETPs created separately for the GMFC major electronic assemblies identified in Table 1.

3.1.1 RF Filter Capacitors

These capacitors are included as C11 and C12 in the EMI Filter. They serve as 0.15 uF RF EMI suppression filters for the 115 VAC input signal to the EMI Filter. The ASIA identified three distinct aging mechanisms as follows:

1) Internal solder deficiencies coupled with thermal fatigue can result in cracks at the solder attachments leading to failed performance

2) Cracks in ceramic capacitor elements coupled with electro-migration that can lead to shorts

3) Fractured glass seals and corrosion that can cause loss of conductivity

All of these failure mechanisms could affect performance characteristics of the device and without completing a piece part dissection and laboratory analysis, it would be impossible to specify root cause of the induced failure. Therefore, these three critical parameters will be combined in test planning and execution and a concerted effort will be directed to monitor the performance characteristics related to these failure modes. The device characteristics of concern include feed through resistance and device capacitance which have specification limits of 0.008 ohms maximum (DCR) and 0.15 uF minimum, respectfully.

The capacitors cannot be fully tested to monitor these parameters when the capacitor is installed in the EMI Filter and the EMI Filter is installed in a fully assembled GMFC.

Figure 3 shows the equivalent circuit of the 115 VAC paths through the EMI Filter.

Figure 3: Partial EMI Filter Equivalent Circuit Diagram

B

A

E12

E4

E8

B1

B3

B2

E15

R1C8 .1uf

L3

L4

400uH

400uH

400uH

400uH

L1B

L1A

L1

E5

E6

C11 .1uf

C12 .1uf2

1115VAC 400Hz

115VDC RETURN

115VAC 400Hz

115VAC RETURN

J2

C9

.33uf C10

.33uf 470 Ohm

J1

E13 E3A2 A3

A1

E11 E14

K1 X2

X1

CR1

E7

+ 28VDC SWITCH

POWER ON

5 28VDC RETURN

E16

CHASSIS GND

Although EMI Filter connector J1 is an external connector on the GMFC, connector J2 is only accessible via partial disassembly of the GMFC. Further, access to J2 provides limited access to the individual capacitors, C11 and C12, for test purposes.

More accurate measurement of characteristics such as capacitance or feed through DC resistance can be made with the capacitor removed from the circuit, either by completely removing it from the EMI Filter or by gaining access to test points in the EMI Filter assembly with the capacitor installed or by de-soldering one terminal of the component.

In each of these latter cases some disassembly efforts are required to gain access.

Therefore, this parameter will carried over to the SRU level tests as documented in the EMI Filter ETP. Functional tests of the GMFC within the A&S test sequence in both static and dynamic test environments should include basic measurements from J1-A and J1-B to Chassis Ground (i.e., J2-2) to determine if the inductor-capacitor series components (L1B-C11 and/or L1A-C12) are intact. During testing at the GMFC level, the K1 Relay in the EMI Filter can be activated to isolate the J1-A and J1-B signal lines.

3.1.2 Solid Tantalum Capacitors

These capacitors are included as C756 thru C758 in the AC Power Supply. They are 7.5 uF capacitors that serve as power supply filters at the AC Power Supply output for the Roll, Pitch and Yaw control circuits. The ASIA identified two distinct aging mechanisms as follows:

1) Thermal fatigue due to the very thin cathode (MnO2) which can lead to cracks

2) Poor seals and contamination leading to short circuits or cracks

The device characteristics of concern include device capacitance and leakage current which have specification limits of 7.5 UF +/- 10% and 2 uAmp maximum at +25 degrees Celsius, respectfully. These failure mechanisms could affect performance characteristics of the device and without completing a piece part dissection and laboratory analysis, it would be impossible to specify root cause of the induced failure. Therefore, these critical parameters will be combined in test planning and execution and a concerted effort will be directed to monitor the performance characteristics related to these failure modes.

The most accurate measurement of capacitor characteristics such as capacitance or leakage current can be made with the capacitor removed from the circuit by completely removing it from the Power Supply or by lifting one terminal of the component. In each of these latter cases some extensive disassembly efforts are required to gain access. Both of these efforts would require disassembly of the GMFC, removal of the Power Supply, removal of the conformal coating, and de-soldering of the capacitor leads. These activities could damage the device and /or the power supply. These capacitors can be fully tested to monitor these parameters with the capacitors installed in the AC Power Supply and the Power Supply installed in a fully assembled GMFC. Figure 4 shows the equivalent circuit of the electrical paths through the AC Power Supply.

Figure 4: Partial AC Power Supply Equivalent Circuit Diagram All of the connector P1 interface pins on the right side of the diagram in Figure 4 are directly wired to either J2 or J3 on the GMFC, with the exception of pin 54 which is wired as in input to the Gyro Interface CCA. Therefore sufficient access to all three of the age sensitive solid tantalum capacitors is provided for parametric testing at the GMFC level.

3.1.3 Wet Tantalum Capacitors

There are 15 wet tantalum capacitors used in the GMFC. They are all specified to meet the requirements of MIL-PRF-39006/09. Seven of the devices are in the EMI Filter (C1 thru C7), while two are located in the AC Power Supply (C792 and C779) and six are in the DC Power Supply (C607-C608, C612-C613, and C615-C616).

Capacitors C1-C7 are in parallel in the EMI Filter for noise suppression on the 28V power signal lines that pass through the filter. Since 110 uF capacitors are about the limit for all practical purposes for applications that require rated voltages in the 50 to 100 volt range, trade studies likely resulted in a circuit design that uses multiple capacitors in parallel to meet the design requirements for noise suppression.

The six wet tantalum capacitors used in the DC Power Supply (C607-C608, C612-C613, and C615-C616) all serve as noise suppression and voltage/current smoothing devices for the +5 Volt, +15 Volt and -15 Volt supply lines from the T602 transformer in the supply.

Similarly, capacitors C779 and C792 provide filtering and noise suppression for the +28 VDC input received from the DC Power Supply via splice joint E1 at P1-4 on the AC Power Supply.

The ASIA identified four distinct aging mechanisms as follows:

1) Metal migration leading to high leakage currents

2) Metal migration leading to electrical shorts across the capacitor

3) Thermal decomposition of the electrolytic gel changing the capacitance value

R762, 10k

115VAC 400Hz

115VAC RTN

P1

P1

From EMI Filter J2

C756 7.5 uF

C757 7.5 uF

C758,

7.5 uF

R760, 10k

R761

1/4w

C759

1 uF

T701

400Hz Rx Excit.33

GWS 0 T.P.

GWS Common

Rx Excit. T.P.

GWS 0

PITCH GWS 90

BITE GWS 0

PITCH GWS T.P.

ROLL GWS T.P.

ROLL GWS 90

YAW GWS T.P.

YAW GWS 90

4) Metallic corrosion due to chlorine contamination causing loss of continuity of high leakage currents

All of these failure mechanisms could affect performance characteristics of the device and without completing a piece part dissection and laboratory analysis, it would be impossible to specify root cause of the induced failure. Therefore, these four critical parameters will be combined in test planning and execution and a concerted effort will be directed to monitor the performance characteristics related to these failure modes.

The device characteristics of concern include device capacitance, leakage currents, and device continuity (not shorted). The following table presents a subset of the device specification limits that apply to these characteristics.

Table 3. Device Specifications for Wet Tantalum Capacitor Aging Concerns

The following discussions help define whether or not these capacitors can be fully tested to monitor these parameters with the capacitors installed in the EMI Filter or Power Supply and the assembly installed in a fully assembled GMFC.

Figure 5 shows the equivalent circuit of the electrical paths containing C1-C7 in the EMI Filter.

Figure 5: Partial EMI Filter Schematic showing C1-C7 In-Circuit

Given the circuit constraints, these capacitors can be marginally evaluated in-circuit to determine total leakage current, total capacitance, and whether or not one or more capacitors might be shorted. Functional tests of the assembled GMFC within the A&S test sequence in both static and dynamic test environments should include basic measurements from J3-32 to J2-88 to determine the capacitor total leakage current, total circuit capacitance and continuity. (Note: GMFC connector J3-32 connects to EMI Filter

25 C 85-125 C -55 Deg C 85-125 Deg C

EMI Filter 8783 C1-C7 110 uF 10% 75 9 uA 36 uA -35% 20%

AC PS 8783 C779 110 uF 10% 75 9 uA 36 uA -35% 20%

AC PS 8674 C792 33 uF 10% 15 1 uA 2 uA -28% 14-16%

DC PS 8680 C607 & C608 120 uF 10% 15 1 uA 7 uA -28% 17.5-20%

DC PS 8720

C612-C613 &

C615-C616 150 uF 10% 30 2 uA 18 UA -48% 13-15%

Assembly Tolerance Part No.

(M39006/09-)

Maximum Leakage Current Capacitance Swing Rated VoltageValueNom.

C

D

E1

E2

C1-C7 110uf

FL1

FL2230uH

230uH

L2

+28VDC

28VDC RTN

+28VDC

+28VDC

28VDC RTN

28VDC RTNE9

E10

J1 J2

J2-4 via splice joint E3 in the GMFC wire harness and GMFC connector J2-88 connects thru DC Power Supply A2P1-32 to A2P1-4 to EMI Filter J2-8).

The following figure shows the equivalent in-circuit diagram for capacitors C607-C608, C612-C613, and C615-C616.

Figure 6: Partial DC Power Supply Schematic showing Wet Tantalum Caps

Circuit constraints limit how effectively these capacitors can be evaluated in a fully assembled GMFC. At the assembled level, determination of total leakage current, total capacitance, and whether or not one or more capacitors might be shorted would include measurements of other circuit components and any failed results or parametric drift over time may not reflect degradation of the wet tantalum capacitors. Functional tests of the GMFC within the A&S test sequence in both static and dynamic test environments should include basic measurements from GMFC J2-93 to J2-7 for C607-C608, J2-69 to J3-31 for C612-C613, and J2-70 to J3-31 for C615-C616 to determine the capacitor total leakage current, total circuit capacitance and continuity.

More accurate measurement of characteristics such as capacitance, continuity, and leakage current on individual capacitors can be made with the capacitor removed from the circuit, either by completely removing it from the DC Power Supply or by de-soldering one terminal of the component. In each of these cases some disassembly efforts are required to gain access. Therefore, this parameter will be carried over to the SRU level tests for further evaluation as documented in the DC Power Supply ETP.

3.1.4 Ceramic Capacitors

A total of 269 ceramic capacitors are used in the GMFC SRUs. The ASIA study identified that both thermal fatigue and copper/silver diffusion into the bulk solder joint

P1

R760 10k

R604

1w

C610

2200 pF

200V

T602

+5 VDC FCSE T.P

(Plus 6 other pins for distribution to CCAs)

R605

1w

C611

2200 pF

200V

C605, 2200 pF

200V

R760, 22

C606, 1000 pF

200V

C607

120 uF

15V

C638

100 pF

200V

C608

120 uF

15V C609

1 uF

L601, 300 UHL600, 300uH

L603, 500 UH

L602, 500 UH

C612

150 uF

30 V

C613

150 uF

30 V

C614

1 uF

R609

11.8k

L604, 500 UH

C615

150 uF

30 V

C616

150 uF

30 V

L605, 300 UH

C617

1 uF

-15 VDC

to A2A2

A GND to

A2A2

15 VDC

to A2A2

+15 VDC

Feedback to A2A2

+5 VDC

15 VDC FCSE T.P

(Plus 8 other pins for distribution to CCAs)

+15 VDC T.P

(Plus 8 other pins for distribution to CCAs)

D GND

(Plus 6 other pins for distribution to CCAs)

D GND

A GND FCSE T.P

(Plus11 other pins for distribution to CCAs)

-15 VDC

+15 VDC

A GND

could cause cracks in the capacitor element. Although not specifically found in the limited samples dissected in ASIA study, identical samples studied in the past had manufacturing defects such as voids and de-laminations in the elements. Although the manufacturing defects themselves are not a problem (since the capacitor meets its rated electrical specifications), they are a mechanical stress point for fracture of the ceramic material as the capacitor is overstressed or subjected to repeated cycles of stress. Any defects noted can be traced back to a specific manufacturer and production dates since the components have manufacturer and date codes.

The only way to know whether a ceramic capacitor has cracks, internal voids, or de-laminations is to destructively cross section the component and examine it under a microscope. Note that many of these components are used as “filter capacitors,” which typically cannot be tested adequately in-circuit because their function is often to provide a high-pass filter for electrical noise (bypass to ground). Environmental stress testing of the GMFC is the best way to find these problems outside of destructive testing.

3.1.5 Metalized Paper-Plastic Capacitors

A combination of 30 metalized paper-plastic fixed capacitors is used in the GMFC.

These capacitors have been generally used in low current applications due to their compact footprint and high reliability. The ASIA identified that a manufacturing defect, fractured glass seals, leading to long term corrosion of the aluminum capacitor plates can lead to loss of terminal conductivity in these devices. Although the manufacturing defects themselves are not a problem (since the capacitor meets its rated electrical specifications) they can allow long term corrosion of the capacitor plates and eventual failure of the device. Any defects noted can be traced back to a specific manufacturer and production dates since the components have manufacturer and date codes.

The only way to know whether or not a fixed capacitor has a fractured glass seal, is to destructively cross section the component and examine it under a microscope. Note that many of these components are used as “filter capacitors,” which typically cannot be tested adequately in-circuit because their function is often to provide a high-pass filter for electrical noise (bypass to ground). Environmental stress testing of the GMFC is the best way to find these problems outside of destructive testing.

3.1.6 Diodes

A total of 51 rectifier diodes and transient suppressor diodes are used among the GMFC SRUs. The ASIA identified that cracks in the glass body of the diode leading to contamination and/or corrosion of the junction or lead attachments are the source of aging concerns for the device. Cracks that cause diode failure can be found in functional testing of the GMFC. Cracks that will eventually lead to failure may be identified by functional testing when the GMFC is under an applied environment of vibration and temperature extremes.

3.1.7 Zener Diodes

Three types of zener diodes are used within the GMFC. A 6.2 volt zener is used in both the DC Power Supply (CR621) and BITE CCA (CR416), while the second device type, a

9 volt zener, is used twice on the AC Power Supply (CR700 and CR705) and once in the DC Power Supply (CR615), and the third type, a 5.1 volt zener is used twice in the AC Power Supply (CR712 and CR713). In general, these diodes provide minimal voltage changes over a wide temperature range and are commonly used in circuit designs requiring a stable voltage reference. The ASIA identified two distinct aging mechanisms for the zener diodes as follows:

1) Electro-migration of lead which drives higher leakage currents

2) Cracks in the glass body of the diode that exacerbates metal migration due to moisture ingress

Functional tests of the assembled GMFC within the A&S test sequence in both static and dynamic test environments will include verification of the zener diode functionality based on circuit functionality. The simplest circuits that contain zener diodes in the GMFC include many other circuit components that cannot be isolated to permit evaluating the reverse leakage currents of the diode itself. Further, changes to those leakage currents over time would be difficult at the GMFC assembly level as the specified maximum allowable range at the piece part level is 0.2 to 15 micro-ampere based on temperature.

More accurate measurement of leakage current on an individual zener diode can be made with the diode removed from the circuit, either by completely removing it from the SRU or by de-soldering one terminal of the component. In each of these cases some disassembly efforts are required to gain access. Since these diodes are directly tied to specific circuit functions and are integrated into the various SRUs, evaluation of these aging issues should be carried over to the SRU level tests as documented in the separate sub-assembly ETPs.

3.1.8 EMI Filter Capacitors

The EMI Filter in the GMFC houses 2 EMI filter capacitors or line filters identified as FL1 and FL2 in the engineering data. The line filters meet Mil-STD M15733/58 and are dash number -0001 parts. They serve as a combination shunting capacitor and line inductor resulting in a low pass filter at the +28VDC input and return lines in the EMI Filter Assembly. The line filter has a maximum rated current capacity of 2.0 amps. The ASIA identified cracks in ceramic capacitor elements coupled with electro-migration that can lead to shorts as the single aging mechanism for this device. The device characteristics of concern include feed through resistance and isolation to chassis ground.

The maximum DC resistance is specified at 0.1 ohm.

The line filters, FL1 and FL2 cannot be tested to monitor these parameters in a completely isolated fashion when they are installed in the EMI Filter and the EMI Filter is installed in a fully assembled GMFC. Figure 7 shows the equivalent circuit of the +28 VDC paths through the EMI Filter.

Figure 7: Partial EMI Filter Schematic showing FL1 and FL2 In-Circuit

Given the circuit constraints, FL1 and FL2 can be partially evaluated in-circuit to determine total DC resistance along the signal path (to include line resistance and the DC resistance component of L2) as well as the DC isolation between the EMI Filter J1 and J2 interface connector pins shown in Figure 7 and chassis ground (J2-2). Functional tests of the assembled GMFC within the A&S test sequence should include basic measurements from J1-C to GMFC J3-32 to determine the total DC resistance across FL1 and from GMFC J3-32 to chassis ground to verify isolation across FL1. Similar measurements for FL2 would be from J1-D to GMFC J2-88 to determine the total DC resistance across FL2 and from GMFC J2-88 to chassis ground to verify isolation. (Note: GMFC connector J3- 32 connects to EMI Filter J2-4 via splice joint E3 and GMFC J2-88 connects thru DC Power Supply A2P1-32 to A2P1-4 to EMI Filter J2-8).

More accurate measurement of DC resistance and chassis isolation on individual line filters can be made with the filters removed from the circuit, either by completely removing it from the EMI Filter or by de-soldering one terminal of the component. In each of these cases some disassembly efforts are required to gain access. Therefore, this parameter will carried over to the SRU level tests as documented in the EMI Filter ETP.

3.1.9 ICs

The integrated circuits used in the GMFC are included in the BITE, Roll, Pitch, Command and Gyro CCAs as well as the AC Power Supply. The ASIA identified multiple manufacturing defects that could lead to eventual component failure. In addition, wear and tear through normal use could deteriorate the LED in the Optical Isolator of the BITE and Pitch CCAs causing component failure.

The only ways to know whether or not an IC contains any of the described aging mechanisms is to destructively cross section the component and examine it under a high power microscope. Note that these components are tested in-circuit because their function is paramount to the functionality of the SRU and the GMFC as a unit.

Environmental stress testing of the GMFC is the best way to find these problems outside of destructive testing.

C

D

E1

E2

C1

110uf

FL2

230uH

230uH

L2

+28VDC

28VDC RTN

+28VDC

+28VDC

28VDC RTN

28VDC RTNE9

E10

J1 J2

FL1 C2

110uf

C3

110uf C4

110uf

C5

110uf C6

110uf

C7

110uf

E16

CHASSIS GND

3.1.10 Inductors

Inductors are included in the EMI Filter, DC Power Supply and AC Power Supply within the GMFC for signal filtering. The ASIA documented that a breakdown of the insulation coupled with thermal stress can result in an increase in equivalent series resistance or shorts in the inductor coils. Problems due to insulation degradation of wound components can be found during functional testing of the GMFC, and aging degradation can be brought out through environmental stress testing.

3.1.11 Relays

Relays are used on the EMI Filter and on the BITE, Roll, Pitch, Command and Gyro CCA SRUs. The ASIA identified two distinct aging mechanisms for the relays as follows:

1) Contact wear, contact contamination, and/or copper diffusion in the contacts that lead to high resistance in the contact path or open path conditions

2) Breakdown of the coil insulation coupled with thermal stress can result in unacceptable pull-in or inoperable relays

Relay contact wear can be evaluated by visual inspection using a microscope (approximately 30X magnification). However, this requires that the metal cover on the relay be removed by destructive means. Further, the contacts are more easily examined if the relay is dissected so that the contact pads can be individually exposed for viewing.

The condition of the relay contacts and coils can be judged indirectly by precisely measuring the contact resistance. In some cases, it is possible to make the precise measurement by connecting test leads at the SRU external connector. However, in some cases additional circuit components may have to be included in the measurement path due to circuit constraints. In all cases these measurements should be made at the SRU level to obtain the most precise measurement possible. Therefore, the parameters will be carried over to the SRU level tests as documented in the appropriate SRU ETPs.

3.1.12 Transformers

Seven transformers are used in the design of the two GMFC power supplies. The DC Power Supply includes 3 transformers while AC Power Supply employs 4 of the devices.

The ASIA study identified breakdown of the insulation coupled with the effects of thermal stress could lead to increased series resistance or shorts in the inductor coils.

Problems due to insulation degradation of wound components can be found during functional testing of the GMFC, and aging degradation can be brought out through environmental stress testing.

3.1.13 Transistors

Transistors are used in all of the GMFC SRUs with the exception of the EMI Filter. A total of 52 transistors provide the signal switching required for the extensive array of logic circuits in the CCAs as well as the current/voltage gains (power amplifiers) required in the AC and DC Power Supplies. Thermal fatigue associated with the comparatively low melting point of the Au-Si die attachments (eutectic alloy composition) was the critical aging mechanism identified in the ASIA study concerning the transistors.

Environmental stress testing is the best way to observe aging problems due to thermal stress by carefully monitoring the voltage levels of the power transistors and the I/O of the logic functions.

3.1.14 Circuit Board Substrate

Fatigue leading to cracks in the conductive paths of the substrate was identified as the aging mechanism associated with the circuit board substrates. Conductor cracks that fail open may be detected during ground testing such as Level I or Service STAR testing.

However, it is possible to have fatigue cracks in the conductive paths which close and maintain the electrical connection. Thus, a visual inspection of substrates in concert with disassembly actions is recommended to help identify fatigue-related cracks in the conductors. Cracks in conductive paths should be detected as circuit failures during functional tests under an applied environment of vibration and temperature extremes during A&S testing.

3.1.15 Discrete Wire

Fatigue or age inducted cracking in the wire insulation leading to chaffing or wire breaks were identified as the aging mechanisms of concern for the discrete wires in the GMFC.

A visual inspection of wire harness in concert with disassembly actions will help identify fatigue and cracking. Wire breaks will be detected as a normal course of functional testing in both the static tests and environmental tests of the GMFC.

3.1.16 Connectors

Three military standard connectors, J1, J2 and J3 provide the interface for the input/output signal paths for the GMFC. In addition, J2/P2 on the EMI Filter and P1 on each circuit card assembly (A2 and A4 thru A9) along with the mating connectors (XA2 and XA4 thru XA9) provide internal assembly interfaces. Moisture ingress and corrosion resulting in increased resistive paths between the pins and/or possible open circuits were the aging mechanisms defined in the ASIA. A visual inspection of each connector in concert with disassembly actions will help identify moisture and corrosion issues.

3.1.17 EMI Seal

The EMI Seals (or gaskets) provide GMFC assembly level protection from extraneous signal noise and/or electromagnetic impulses. The seals are made from a bulk material specified as Elastomet, P/N 82-91446, which was originally manufactured by Tecknit (now part of Parker Hannifin Corp’s Chromerics Division, CAGE 07700). The ASIA identified embrittlement and cracking leading to a loss in EMI protection as its only distinct aging mechanism.

A continuity test between top and bottom covers to the housing and between J1, J2 and J3 to the housing must be less than 2.5 milliohms at each interface to meet stated performance requirements. A visual inspection of each gasket upon disassembly should provide a valid determination if the gaskets are becoming brittle or cracked.

3.2 A&S Parametric Test Methods and Environments for GMFC Assembly This section provides recommended GMFC test methods based on the testing requirements identified in Section 3.1 above. The following test methods will not damage the GMFC, potentially allowing it to be placed back into service. The recommended random vibration and temperature environments were established based on the acceptance tests conducted following the stringent Production Reliability Verification Test thermal cycling environments (reference 232-11267). These test levels are commensurate although not exactly equal to those defined in the Acceptance Test Procedures for the ALCM Warhead Arming Device and Rotary Switch for individual acceptance of those units.

The original Acceptance Test Procedure for the GMFC was not provided for use in the development of the GMFC A&S Program, however, since the WAD, Rotary Switch and GMFC are installed adjacent to each other in the missile and the GMFC PRVT test follows the ATPs for the other ALCM flight hardware, it seems appropriate to use the identical environments for GMFC A&S purposes. The recommended non-destructive tests may provide indications of possible aging effects of internal components, and thus may be beneficial for screening of samples to select candidates for disassembly and more detailed inspection.

The testing described below is intended to gather specific data to be recorded and tracked by the A&S program for the purpose of monitoring aging effects. Data captured in other test programs, such as Service STAR or Functional Ground Test, may be used to augment the analysis efforts within the A&S Program, so long as the data can be correlated with age.

3.2.1 Visual Inspection, External

The GMFC assembly should be inspected for the following types of aging and damage:

• Worn pins and sockets in connectors

• Damaged connector inserts and hermetic interfacial seals

• Damaged housing, (dents, cracks, corrosion, etc.)

• Loose fasteners

Any visible evidence of aging-related or handling damage should be photographed for documentation purposes. Any bent connector pins should be noted before electrical tests are attempted. Loose fasteners may indicate loss of EMI gasket integrity. Do not attempt to judge fastener torque by tightening the fastener (which could damage the EMI gaskets, strip the fastener, or even break the fastener).

3.2.2 Functional Tests

Functional test capabilities are recommended such that the GMFC can be tested independent of the missile and can be tested under environmental conditions. It will be necessary to confirm periodically that dedicated A&S samples still provide basic functionality, in addition to the recommended tests to collect A&S monitoring data.

Also, certain aging effects (e.g., failures due to component and solder defects, loss of conformal coating seal integrity, etc.) may become apparent during a functional test, particularly if the test is performed while the GMFC is under thermal and vibration environments. Many age related failure mechanisms can only be directly detected through destructive analytical means however all of these mechanisms can be isolated through extensive functional testing and subsequent post test failure analysis.

A functional test can be developed based on the automated GMFC Depot Level Test Program (232-38070-35) for individual unit acceptance after depot repairs, but modified to correct identified test deficiencies. The test program is theoretically based on the Level III Test Requirements Document (232-12126) which is also available for reference.

If necessary, the Product Reliability Verification Test Procedure (PRVT Procedure, 232- 11267) and the Functional Test Procedure (232-11764) are also available for reference.

The random vibration test levels for each of the three axes are as follows:

Frequency Spectrum Level

10 Hz to 34 Hz 0.0014 g2/Hz

34 Hz to 100 Hz Ramp 0.0014 g2/Hz to 0.014 g2/Hz

100 Hz to 2000 Hz 0.014 g2/Hz

Table 4. Random Vibration Levels

The recommendation for A&S testing, based on the ALCM engineering documentation and the goals of the A&S program, is for performing vibration for each axis at temperature for the duration of one functional test (about 10 minutes at each axis). If the functional test runs longer than 15 minutes, the GMFC should be subjected to cooling air flow per the PRVT Test Procedure.

Temperature environments for the GMFC should include ambient, cold and hot temperature cycles. The following temperatures and estimated durations have been extracted from the PRVT test procedures.

Temperature Duration

Ambient (72F) 10 minutes -65F +/- 3.6F 2 Hrs 33 minutes

+152F +/- 3.6F 1 Hrs 27 minutes

Table 5. Temperature Test Levels

The temperatures and time durations specified in Table 5 include requirements to ramp between the temperature plateaus within 25 minutes minimum. These ramp times are requirements considered excessive for the A&S program and can be adjusted to prevent unnecessary shock to the test articles. To provide a functional test under environments for the A&S program these temperature and vibration levels can be combined with functional testing at each axis as follows:

Temperature Soak Duration Vibration Duration Axis

+152F 120 minutes 10 minutes X

Ambient (72F) 120 minutes 10 minutes Y

-65F 120 minutes 10 minutes Z

Table 6. Combined Environmental Test Levels

Notes: 1. Temperature ramping shall not exceed 5F per minute.

2. Functional Testing of the GMFC occurs during the 10 minute vibration period at the end of the temperature soak.

3.2.3 RF Filter Capacitor Tests

Several measurements on the EMI Filter RF filter capacitors (C11 & C12) can be made in-circuit at the GMFC assembly level. Those measurements are described in the following table.

Circuit Elements

Stimulus (S)

Measure (M)

Units Data

Format

GMFC

Connector/Pins Measurement

Measurement Limits

C11, C12, & L1B M nF XXX.X J1-A Chassis Capacitance (Cp)

@ 1k Hz 200 < Cp < 400

C11, C12 & L1A M nF XXX.X J1-B Chassis Capacitance (Cp)

@ 1k Hz 200 < Cp < 400

C11, C12 & L1B M Ω XX.XX J1-A Chassis Impedance (Rs)

@ 1k Hz 2 < Rs < 15

C11, C12 & L1A M Ω XX.XX J1-B Chassis Impedance (Rs)

@ 1k Hz 5 < Rs < 25

C11, C12 & L1B M nF XXX.X J1-A Chassis Capacitance (Cp)

@ 10k Hz 400 < Cp < 600

C11, C12 & L1A M nF XXX.X J1-B Chassis Capacitance (Cp)

@ 10k Hz 400 < Cp < 600

C11, C12 & L1B M Ω XX.XX J1-A Chassis Impedance (Rs)

@ 10k Hz 1 < Rs < 5

C11, C12 & L1A M Ω XX.XX J1-B Chassis Impedance (Rs)

@ 10k Hz 1 < Rs < 5

Table 7. RF Filter Functions that can be Tested at External GMFC Connectors

During testing at the GMFC level, the K1 Relay in the EMI Filter can be activated to isolate the J1-A and J1-B signal lines allowing a test of C11 & L1B or C12 & L1A thus reducing the circuit elements included in each test and providing additional performance information.

3.2.4 Solid Tantalum Capacitor Tests

Performance characteristics including capacitance and leakage current can be used to characterize aging effects for the parts. Solid tantalum capacitors C756, C757 and C758 in the AC Power Supply can be tested for both capacitance and leakage current using the appropriate external GMFC connector J2 pins. The following table presents the J2 and J3 interface pins for the leakage current and capacitance tests for these parts.

Circuit Elements

Stimulus (S)

Measure (M)

Units Data

Format

GMFC

Connector/Pins Measurement

Measurement Limits

C756 M uF XX.XX J2-49 J2-48 Capacitance 7.5uF +/- 10% C756 M uA XX.XX J2-49 J2-48 Leakage Current 2 uA Maximum C757 M uF XX.XX J2-50 J2-48 Capacitance 7.5uF +/- 10% C757 M uA XX.XX J2-50 J2-48 Leakage Current 2 uA Maximum C758 M uF XX.XX J2-51 J2-48 Capacitance 7.5uF +/- 10% C758 M uA XX.XX J2-51 J2-48 Leakage Current 2 uA Maximum

Table 8. AC Power Supply Solid Tantalum Capacitor Tests at GMFC Connector J2

The capacitance tests can be straight forward measurements while 32 VDC can be applied across individual capacitors and the leakage current can be measured.

3.2.5 Wet Tantalum Capacitor Leakage Current and Capacitance

The combined or total capacitance and/or leakage currents of the seven 110…