LAT  Electronics, Data Acquisition & Instrument Flight Software

  Subsystem Manager:  Gunther Haller

 

Important: EM2 test-stand hardware components are NOT compatible with hardware supplied for EM1 test-stands. Do not mix TEM/TEM-PS/Transition Card EM1 with EM2 hardware. Hardware for EM2 is marked "EM2" on the TEM, TEM-PS, VME Transition Card and LCB supplied.

Documents:

The documents are in the process of being transferred to the LAT-DOC system for official release, please retrieve them from LATDOC's.

Here are applicable document numbers and selected copies of the documents in the release cycle (use them with caution).

Note that we do not perform impedance/short/open/voltage measurements on all pins, but test functionality of the system. The "safe-to-mate" test is the responsibility of the sub-system.

Calorimeter:

EGSE-CAL-FM TESTSTAND #2

LAT Quality Assurance

Performance & Safety Assurance LAT NCR Report

The following Nonconformance Report # 00245 was submitted on 12/01/04 14:04:11

 

Entered by Ludvik, Jeffrey - jsludvik@slac.stanford.edu

 

Found by:  Customer Complaint

Type of Nonconformance:  Minor

Discrepancy Level:  Non-Flight Hardware

Sub-System:  Electronics (ELEC)

Item Description:  EGSE CAL FM02 TPS

Supplier: 

Location: 

Drawing/Rev #:   

Lot/Heat #: 

Serial #:  TPS GLAT0611

Test Procedure/Rev #: 

 
Description of Nonconformance:  NRL reported the problem (PRB-0471) as follows: "When powering up the calorimter (CAL104) in TVAC chamber there is 40mA drawn from the 28V supply. This is very low compared with the nominal 340mA - 450mA that we are expecting. Additionally, the TEM is unresponsive to the TEM power up commands. While disconnecting the power supply from the TEM, we noticed that the connector JS1 is loose. Suspect that the connection between the PDU cable and JS1 on the power supply is not making good contact or have internal contacts broken. After verifying JS1 connection internally and fixing the socket, the TEM still draws low current from the 28V supply and TEM is unresponsive to commands. Will send PS back to SLAC for futher analysis."

The TPS was received by SLAC. The TPS was tested immediately and it was found the TEM 3.3V was not working. Further investigation found that the L2 inductor created an intermittent connection when physically moved back and forth, turning the TEM 3.3V on and off. It looks as though the inductor lead was broken during vibration.
       

Disposition Area

Defect Code:  000 Conformal Coating

Disposition:  Rework 
(Valid  dispositions:  Rework, Repair, Use-as-is, Reclassify, Return to Vendor, Scrap, or Documentation Change)

Disposition Instructions:  
The non-flight inductor L2 on the EGSE CAL FM02 TPS was found to have a broken lead. This was due to incomplete staking of the inductor. The staking was done in house at SLAC and not at an outside vendor per drawing. A large gap of no staking compound was visible under the inductor which could be moved easily. The inductor lead was re-soldered. All the inductors were staked with epoxy.

The TPS was tested and passed all performance electrical testing. This TPS will be returned to NRL when this NCR is closed.

Root Cause:  Incomplete staking of inductor.

Action taken to Preclude Recurrence of Discrepancy: 
All flight TPS are staked and conformal coated at an outside vendor and done to specification according to the release drawing.