GLAST LAT ProjectOct DAQ & FSWV3 1 GLAST Large Area Telescope: Electronics, Data Acquisition & Flight Software W.B.S Analysis of cPCI Backplane Connector Assembly xray’s Gunther Haller (650) Gamma-ray Large Area Space Telescope

GLAST LAT ProjectOct DAQ & FSWV3 2 Backplane Analysis Method: give following information for each backplane –Starting point: list of pins supplied by GSFC identified as possibly under-fill –Identify pins in that list which are not used Pins already identified on SLAC’s spread-sheet Pins not on the spread-sheet –There is no reason to spend time discussing the fill of any pins not used anyways –Of the remaining pins, list of pins used Pins already identified on SLAC’s spread-sheet Pins not on the spread-sheet Discuss fill of both

GLAST LAT ProjectOct DAQ & FSWV3 3 Notes (1) Number of pins soldered on backplane excluding shield-pins (which are not used and thus ignored) –P1: 25 rows –P2: 22 rows –P3: 19 rows –P4: 25 rows –P5: 22 rows –Each row: columns Z, A, B, C, D, E, F Z and F are shield pins, not used –Total number of pins potentially used –113 x 5 = 565 for each slot, times 4 slots = 2,260 pins –Identification of 4 slots X1: CPU (3u-card in P1, P2) X2: CPS (3u-card in P4, P5) X3: SIB (6u-card in P1-P5) X4: LCB (6u card in P1-P5) Connectors not used for flight –X1: P3, P4, P5 –X2: P1, P2, P3 –X3: P2, most of P3 (P3 only uses: A19 (dclk); A1-E1 (gnd); A5-E5: (3.3V); B8-B14 (gnd); gnd and 3.3V redundant on other connectors) –X4: P2, P3 Following connector are used for EGSE only, thus ignored for flight crates –X1: P4/P5 holds custom Serial card, not used/integrated for flight –X2: P1/P2 holds commercial Ethernet card, not used/integrated for flight

GLAST LAT ProjectOct DAQ & FSWV3 4 Notes (2) Comment to intentionally shorted shield pins (3 pins on row Z or row F) apparent on some xrays –Mostly, center pin identifies row in which pin was to be touched-up –Wanted some kind of indication that correct pin was in fact touched-up just in case that no change might be apparent before/after touch-up –Shorts were removed after xray but before QA, although shorts would have no effect since Shield pins already shorted to each other via board/connector LAT does not use shield pins anyways

GLAST LAT ProjectOct DAQ & FSWV3 5 First Flight Backplane 2414 Total of ~ 2,000 pins looked at in xray 22 pins identified on GSFC list Not used (18 pins) –Already identified on SLAC list X1: P5-D11; P5-C12; P5-D12; X2: P1-B17 X3: P1-B17 –Not used from remaining identified (X1-P5, X2-P1 not used as stated) X1: P5-E11 X2: P1-A19 X2: P2-C10, B11, C11, D11; P4-C6 X3: P1-B2 ; P1-B6 (red+5); P5-B2 (ch-gnd); P5-C14 (red+5), P4-B21 (redGND); X4: P5-B5 (red+3.3) Used –Already identified on SLAC list X1: P1-B15 (Frame#); X3: P1-A7 (AD30); –Not on SLAC list X1: P1-C23 (AD3) ; X3: P1-D16 (stop_n)

GLAST LAT ProjectOct DAQ & FSWV3 6 Second Flight Backplane 2415 Total of ~ 2,000 pins looked at in xray 18 pins identified on GSFC list Not used –Already identified on SLAC list (7 pins) X2: P1-B3; P4-A15; P4-B23; X3: P1-B8; P2-C12; J4-C1, J4-C16 –Not used from remaining identified X1: P1-A19 (3.3V, one of 7 pins, not needed) X3: P2-B12; P3-C1 (red+5), C3 (red+5), E4 X4: P1-B1 Used –Already identified on SLAC list X4: P1-C23(AD3); P4-C11(EI_PRIM_5_N); P4-C21(EI_PRIM_2_P) –Not on SLAC list X1: P1-B19 (AD15), P1-A20 (AD12) ;

GLAST LAT ProjectOct DAQ & FSWV3 7 Third Flight Backplane 2420 Total of ~ 2,000 pins looked at in xray 5 pins identified on GSFC list Not used –Already identified on SLAC list None –Not used from remaining identified X1: P2-C21 X2: P1-D25 X3: P2-E8, B13 X4: P5-C22 Used –none

GLAST LAT ProjectOct DAQ & FSWV3 8 Fourth Flight Backplane 2418 Total of ~ 2,000 pins looked at in xray 16 pins identified on GSFC list Not used –Already identified on SLAC list None –Not used from remaining identified –X1: P2-B5, P4-E7, D8, E8, D9 (P4 not used) –X2: P1-D11, B23, B24, C24; P2-B1, C1; (P1, P2 not used) –X2: P4-C9 (red+5); P5-A5 (red-28) –X4: P5-D21 Used –Already identified on SLAC list None –Not on SLAC list X1: P2-B6 (GBM RDNT) X3: P1-E7 (AD27)

GLAST LAT ProjectOct DAQ & FSWV3 9 Fifth Flight Backplane 2419 Total of ~ 2,000 pins looked at in xray 6 pins identified on GSFC list Not used –Already identified on SLAC list X1: J5-C13, B15 –Not used from remaining identified X1: P5-C15, A18 (X1-P5 not used) X3: P2-D10 X4: P2-A10 Used –none

GLAST LAT ProjectOct DAQ & FSWV3 10 First Flight Spare Backplane 2416 Total of ~ 2,000 pins looked at in xray 42 pins identified on GSFC list Not used –Already identified on SLAC list (17) X1: P2-C10 X2: P1-D11, A17, D19, A21 (P1 not used as indicated) P1-D11, A17, D19, A21 (X2 not used as indicated); P5-B6, C6 (redundant as indicated) X3: P3-A4, B4, C5, D5, D6 (P3 not used as indicated) X4: P3-E10 –Not used from remaining identified X1: P2-B12, B13, C21 X2: D25 (gnd red) X3: P2-A7, B7, A8, B8; P4- D24 (not used), C25(gndred), D25 (not used); X4: P2-B18, C18; P4-D6 (not used), Used –Already identified on SLAC list None –Not on SLAC list X2: P4-D2 (PRIM_SPO1_P), D3 (PRIM_SPO0_N), C25 (CLK_OUT_PRIM_P), P5-D2 (SPARE_TO_LCB_0), B21 (28V_RET), D21 (SPI_PRIM_RDNT_SEL) X3: P1-A22 (AD7); P4-D20 (SC_RDNT_PWR_PDU_RDNT_SEL), P5-A19 (PRIM_1553_P) X4: P4-C23 (EI_PRIM_1_P); P5-D1 (GND)

GLAST LAT ProjectOct DAQ & FSWV3 11 Summary 5 Flight boards (2414, 2415, 2420, 2418, 2419) –> 10,000 pins checked –67 pins called out by GSFC as questionable –Of those 14 were already on SLAC spread-sheet identified as not used –53 pins remaining –Of those 42 are not used (no need to discuss fill) –Remaining are 11 pins to examine (of those 6 were on SLAC list) –Next pages show all 11 pins 1 st flight spare (2416) –42 pins called out by GSFC as questionable –Of those 31 are not used (no need to discuss fill) –Remaining are 11 pins to examine –Next pages show all 11 pins

GLAST LAT ProjectOct DAQ & FSWV3 12 Flight

GLAST LAT ProjectOct DAQ & FSWV3 13 X-ray of pins 2414: X1-P1-B15 GLAT2414 X1 P1 B15 FRAME# Void a bit bigger than on one of the previous cross-sections shown below. Would estimate that to be about 75% fill and the pin on the right to be at least 65%

GLAST LAT ProjectOct DAQ & FSWV3 14 X-ray of pins 2414: X1-P1-C23 GLAT2414 X1 P1 C23 AD3 Fill ~ 75%, based on simple ratio of 3 out of 4 shows solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 15 X-ray of pins 2414: X3-P1-A7 GLAT2414 X3 P1 A7 AD30 Fill >80%, assuming 5 out 6 ratio filled.

GLAST LAT ProjectOct DAQ & FSWV3 16 X-ray of pins 2414: X3-P1-D16 GLAT2414 X3 P1 D16 STOP_N Fill ~ 80%, based on simple ratio of 3.5 out of 4.5 shows solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 17 X-ray of pins 2415: X1-P1-A20 GLAT2415 X1 P1 A20 AD12 80% fill based on 4.5 out of 5.5 fill ratio.

GLAST LAT ProjectOct DAQ & FSWV3 18 X-ray of pins 2415: X1-P1-B19 GLAT2415 X1 P1 B19 AD15 >90% fill.

GLAST LAT ProjectOct DAQ & FSWV3 19 X-ray of pins 2415: X4-P1-C23 GLAT2415 X4 P1 C23 AD3 65% fill based on 2 out of 3 fill ratio.

GLAST LAT ProjectOct DAQ & FSWV3 20 X-ray of pins 2415: X4-P4-C11 GLAT2415 X4 P4 C11 EI_PRIM_5_N >70% fill assuming 2.25 out of 3 fill ratio. Summed voids to get to 0.75 voids.

GLAST LAT ProjectOct DAQ & FSWV3 21 X-ray of pins 2415: X4-P4-C21 GLAT2415 X4 P4 C21 EI_PRIM_2_P 80 % fill assuming 2.4 out of 3 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 22 X-ray of pins 2418: X1-P2-B6 GLAT2418 X1 P2 B6 GBM RDNT 70 % fill assuming 4 out of 5.5 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 23 X-ray of pins 2418: X3-P1-E7 GLAT2418 X3 P1 E7 AD27 65 % fill assuming >3 out of 5 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 24 Flight Spare

GLAST LAT ProjectOct DAQ & FSWV3 25 X-ray of pins 2416: X2-P4-D2 GLAT2416 X2 P4 D2 PRIM_SPO1_P 80 % fill assuming 4 out of 5 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 26 X-ray of pins 2416: X2-P4-D3 GLAT2416 X2 P4 D3 PRIM_SPO0_N 75 % fill assuming 4.5 out of 6 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 27 X-ray of pins 2416: X2-P4-C25 GLAT2416 X2 P4 C25 CLK_OUT_PRIM_P 90 % fill.

GLAST LAT ProjectOct DAQ & FSWV3 28 X-ray of pins 2416: X2-P5-D2 GLAT2416 X2 P5 D2 SPARE_TO_LCB_0 75 % fill assuming 4.5 out of 6 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 29 X-ray of pins 2416: X2-P5-B21 GLAT2416 X2 P5 B21 28V_RET 80 % fill assuming 5 out of 6 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 30 X-ray of pins 2416: X2-P5-D21 GLAT2416 X2 P5 D21 SPI_PRIM_RDNT_SEL 80 % fill assuming 5 out of 6 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 31 X-ray of pins 2416: X3-P1-A22 GLAT2416 X3 P1 A22 AD7 > 65 % fill assuming 4 out of 6 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 32 X-ray of pins 2416: X3-P4-D20 GLAT2416 X3 P4 D20 SC_RDNT_PWR_PDU_RDNT_SEL 70 % fill assuming 3.5 out of 5 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 33 X-ray of pins 2416: X3-P5-A19 GLAT2416 X3 P5 A19 PRIM_1553_P >65 % fill assuming 4 out of 6 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 34 X-ray of pins 2416: X4-P4-C23 GLAT2416 X4 P4 C23 EI_PRIM_1_P >65 % fill assuming 3 out of 5 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 35 X-ray of pins 2416: X4-P5-D1 GLAT2416 X4 P5 D1 GND 70 % fill assuming 4 out of 5.5 solder fill.

GLAST LAT ProjectOct DAQ & FSWV3 36 Conclusion (1) All boards were conformal coated a while ago The boards are at different stages in assembly Touching up boards now will require stripping off some conformal coat (not difficult) Flight –2414: 4 pins ok –2515: 5 pins ok –2420: no issues –2418: 2 pins ok (might touch these up, but no great hope of improvement) –2419: no issues Flight spare –2416: 11 pins. Looks ok although we might try to touch up several of those pins. Touch-up showed good results when under-fill, but varying results when voids –Decided not to use pre-heat equipment on backplane since board is completely covered with connectors not fabricated to be soldered. More risk than benefit in our view. In summary although fill is not ideal and what we would like, it is acceptable considering all other constraints –Qual testing of example boards (using short-open tests) did not show any issue even with 40+ pins filled less than 50% fill, 100+ less than 60%, or 320 < 70% –TC/Vib/Thermal-vacuum did not show any issues on the proto-flight SIU crate (with flight assembled SIB/CPS/LCB/CBP/RAD750) and those boards had more voids and underfill than the above flight backplanes) Definitely improvement from…see next page

GLAST LAT ProjectOct DAQ & FSWV3 37 Conclusion (2) Xray of backplane assembled in same lot as other backplanes (#2411) Passed visual inspection by SA and SLAC (no underfill apparent from solder side) Would have been large risk to fly such a board Shows that recommendation by GSFC to xray boards was definitely good idea to say the least We were able to improve fill via touch-up, but board is only used as secondary spare