Warm Electronics 1

PACS SVR 22/23 June 2006

Warm Electronics: Warm Electronics: Components/Subsystems Test Components/Subsystems Test

ResultsResults

B. Voss

PACS SVR

Warm Electronics 2

PACS SVR 22/23 June 2006

BOLC FM

• errors occurred during thermal vacuum acceptance tests

• three housekeeping channels found unstable during cold start up test (-30°C)

• failure seems to be temperature dependent (possibly a week soldering)

• tests are stopped and BOLC is sent back for repair

• tests will be resumed and partly repeated (vibration in at least one axis)

Warm Electronics 3

PACS SVR 22/23 June 2006

DEC/MEC QM

• equipped with complete nominal section• currently running at MPE• long duration tests

– digital interfaces without errors or malfunctions– analogue interfaces OK except:

• SPU current housekeeping, known problem with wrong gain setting in DEC/MEC. Corrected for FM

• CRE interfaces tested OK during acceptance test, but no long term tests available.

Warm Electronics 4

PACS SVR 22/23 June 2006

DEC/MEC FM

• in production• schedule delayed by two main problems:

– FPGA swap on both DEC Base boards• repair envisaged due week 29• rearranging test order because of availability of test

facilities

– erroneous SPU boards • FM will be temporary equipped with erroneous SPU

boards thus EMC and environmental test can be performed in time

• only small likelihood of malfunction during tests• later exchange of the SPU boards and delta acceptance

Warm Electronics 5

PACS SVR 22/23 June 2006

DEC/MEC FM

• new schedule by CSL:– repair due week 29– functional test and vibration due week 32– thermal vacuum due week 33– functional retest due week 34– EMC test at ESTEC due week 35– delivery to MPE begin of September

Warm Electronics 6

PACS SVR 22/23 June 2006

DPU PFM

• functional Tests at CGS OK• thermal Tests OK• EMC Test OK (minor NCRs, solved/accepted)• possible problems:

– CFM2 showed corrupted memory after some hours of operation at MPE

– AVM2 in same configuration is running stable – possible reasons currently under investigation

(HW or SW problem?)– errors not reproducible at CGS– PFM now at MPE for comparative tests

Warm Electronics 7

PACS SVR 22/23 June 2006

SPU PFM

• thermal tests OK• EMC test OK (minor deviations already

accepted)• functional test failed under special conditions

– during acceptance test campaign 15.05.06 malfunction occurred (CRISA FPL-NC-1214-077-CRS)

– start-up SW reports error during application upload command

– error affects read from DSP program memory (PRAM) with special bit patterns (all 1’s to all but one bit 0’s)

– error is systematic and affects all DSP boards (PACS SPU, PACS DECMEC and LFI REBA)

Warm Electronics 8

PACS SVR 22/23 June 2006

SPU PFM

• reason of error– not clearly understood yet, but most likely a

ground bouncing problem when switching output stages in the PRAMs

• repair– repair of EBB with additional ground wires on the

board improved the situation– modification of flight spare currently under

progress

Warm Electronics 9

PACS SVR 22/23 June 2006

Harnesses

• Warm Interconnect Harness– QM at MPE– QM showed different weaknesses (bad bonding,

wrong back shells, swapped wires in cable bundles)

– FM production will take care of these

• Cryo Harness– complete and tested– differences in resistance measurements

compared to MPE test harness– reason under investigation but most likely due to

different measurement systems