Procedure,_Environmental_Stress_Screening__No._19200-12992072_Attachment_008.pdf

i

Status: RELEASED Date: 1/13/2005 ii

REV DATE DESCRIPTION AUTHORITY APPROVED

0 30 Aug 04 Product Baseline ERR FOM L04M5117 J. B.

W. B.

B. G.

PROCEDURE, ENVIRONMENTAL STRESS SCREENING

19200 – 12992072 REV 0

30 August 2004

TABLE OF CONTENTS

PARAGRAPH TITLE PAGE

1.0 Purpose

2.0 Scope

3.0 Applicable Documents

4.0 Item Description

5.0 General Requirements

5.1 Failures/Discrepancies

5.2 Rescreen and Retest

5.3 Inspection/Test Equipment

5.4 Test Conditions

5.5 Test Data

6.0 Test Procedures

6.1 Pre-ESS Test

6.2 Fixture Preparation

6.3 ESS Temperature & Vibration Profile

6.4 Unit Operation & Data Requirements

Figure 1 Figure 2 Figure 3

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1.0 PURPOSE

This document provides a procedure for the performance of Environmental Stress Screening for the DC/DC Converter Power Supply Module (DC/DC PS) 19200- 12995064, (Reference: Ensign P/N 9034-01) in accordance with the applicable requirements of Performance Specification 19200-12986349 and Environmental Stress Screening (ESS) Requirements document 19207-12462906.

2.0 SCOPE

This document establishes the test requirements and methods used for conducting Environmental Stress Screening of the DC/DC PS. This is required to verify that the manufacturing processes and materials used in each power supply meet the intended design objectives. Environmental stress screening is used to identify and correct any manufacturing or material defects that could fail in the field.

3.0 APPLICABLE DOCUMENTS

The following documents apply to this procedure. In the event of a conflict between documents referenced herein and the contents of this procedure the referenced documents take precedence.

DRAWINGS

19200-12986349 DC/DC PS, Performance Specification for

19200-12995064 DC/DC PS Assembly

19207-12462906 Environmental Stress Screening Requirements

9034-600 Acceptance Test Procedure 9034-601 Acceptance Test Procedure, Data Sheet

4.0 ITEM DESCRIPTION

The DC/DC Converter Power Supply Module (DC/DC PS) is a two part assembly. The assembly consists of a top cover and printed circuit board and a bottom printed circuit board bonded directly to an aluminum baseplate which is the mounting surface and thermal transfer surface. The top cover and bottom base plate form a contiguous EMI bond.

5.0 GENERAL REQUIREMENTS

5.1 Failures / Discrepancies

Any unit that fails to meet the requirements of this ESS procedure or the applicable acceptance test procedure shall be reworked to the requirements of the specification and product documentation.

A failure is defined as any Line Replaceable Unit not meeting the specified requirements of the applicable product specification and drawing due to component failure or manufacturing process error. Failures of test equipment shall not be considered a hardware failure. Test equipment shall be anything other than the DC/DC PS (i.e. shock mounts, slip table, electrical test cables, etc.).

5.2 Rescreen and Retest

Any product that fails as described above shall be retested per the ATP and submitted to ESS for one combined thermal/vibration cycle.

5.3 Inspection / Test Equipment

Inspection/Test Equipment utilized to verify all requirements shall be maintained by a calibration system in accordance with ANSI/NCLS Z540-1-1994 as defined in the contract requirements.

5.4 Test Conditions

Unless otherwise specified, measurements and tests shall be made at standard ambient conditions. These Inspection conditions are as follows:

Temperature ............................................................ 25 ± 10 °C (77 ± 18 °F) Relative Humidity ................................................... uncontrolled room ambient Atmospheric Pressure.............................................. site pressure

The maximum allowable test condition tolerances shall be as follows, unless otherwise specified in an applicable test section of this test document:

Temperature ............................................................ +/- 2°C Vibration:

Frequency.................................................... +/- 2% or ½ Hz below 24 Hz Amplitude (Random)................................... +3 dB/-1.5 dB below 500 Hz .................................................................... +3 dB/-6dB from 500 Hz to 2000 Hz GRMS .................................................................... +/- 10% Elapsed Time .......................................................... +/- 5% Humidity ................................................................. +/- 5% RH Pressure................................................................... +/- 5%

5.5 Test Data

Data taken during this procedure shall include as a minimum:

Vibration profile for the batch.

Temperature data for at least one location on the heat sink.

Output voltages for each unit during the last minute of each temperature extreme.

6.0 TEST PROCEDURES

6.1 Pre-ESS test

6.1.1 Prior to ESS Testing, each unit shall have been tested in accordance Ensign Power

Systems’ 9034-600 Acceptance Test Procedure and data shall have been recorded on Ensign Power Systems’ 9034-601 Acceptance Test Procedure Data Sheet.

6.2. Fixture Preparation and UUT Mounting

6.2.1 Load units on to the heat sinks in the ESS chamber as shown in Figure 1. Torque power supply mounting screws to 6 inch pounds.

6.2.2 Attach chamber control thermocouples as shown in Figure 2. Use the standard accelerometer mounted under the center of the vibration plate for vibration control and monitoring.

6.2.3 Duct air between the heat sinks as shown in Figure 1.

6.2.4 Operate the UUT at 28.0 + 3 VDC. Measure and record the output voltages of each unit.

Verify conformance to the limits specified in Table 1.

Table 1 Outputs Voltage Specifications

+5V 3.50 – 5.50 +15V 13.50 – 15.50 -15V -15.50 – -13.00

6.3 ESS Temperature and Vibration Profile

6.3.1 The HASS chamber temperature and vibration input shall be as shown in Figure 3.

6.3.2 The average product temperature rate of change shall be greater than 23 °C/min for at least 64% (90 °C) of the temperature range.

6.4 Unit Operation and Data Requirements

6.4.1 Each unit shall be operated at a 50% duty cycle, 30 seconds on and 30 seconds off, during the Power On cycles shown in Figure 3.

6.4.2 Data shall be taken to verify proper unit operation during the last minute of each temperature extreme as shown in Figure 3.

Figure 1. Vibration Table setup

Figure 2. Control Thermocouple Location

30 August 2004

Figure 3. Power On cycles