NI SCXI-1175 Relay Replacement

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NI SCXI-1175 Relay Replacement

The NI SCXI-1175 uses electromechanical armature relays.

Refer to the following table for information about ordering replacement relays.

Relay Manufacturer Part Number
AXICOM (Tyco Electronics) IM42GR (3-1462037-1)

Relay Kit Part Number
National Instruments (10 relays) 779356-01

Complete the following sets of steps to disassemble your module, replace a failed relay, and reassemble your module.

Disassemble the Module


  1. Ground yourself using a grounding strap or a ground connected to your SCXI chassis.
    Note  Properly grounding yourself prevents damage to your module from electrostatic discharge.
  2. Remove the three rear screws from the back of the module.

    1 Rear screws
    2 Top cover
    3 Rear panel
  3. Carefully remove the top cover of the module using a flathead screwdriver.

  4. Remove the rear panel.

  5. Remove the hex standoffs from the front of the module.

    1 Hex standoffs
  6. Slide the relay assembly out of the enclosure.

    1 Relay assembly
    2 Enclosure
  7. Remove the four screws that secure the mezzanine board to the base board.

    1 Screws
    2 Mezzanine board
    3 Base board
  8. Separate the mezzanine board from the base board.

  9. Locate the relay you want to replace. Refer to the following figures and table for relay locations.

    Base Board

    Mezzanine Board


    1-Wire 196×1
    Channel Name
    2-Wire 95×1
    Channel Name
    2-Wire 98×1
    Channel Name
    Relay
    Name
    CH0 CH95 CH0 CH0 K97
    CH1 CH96 CH1 CH1 K93
    CH2 CH97 CH2 CH2 K89
    CH3 CH98 CH3 CH3 K85
    CH4 CH99 CH4 CH4 K81
    CH5 CH100 CH5 CH5 K77
    CH6 CH101 CH6 CH6 K73
    CH7 CH102 CH7 CH7 K69
    CH8 CH103 CH8 CH8 K65
    CH9 CH104 CH9 CH9 K61
    CH10 CH105 CH10 CH10 K57
    CH11 CH106 CH11 CH11 K53
    CH12 CH107 CH12 CH12 K47
    CH13 CH108 CH13 CH13 K44
    CH14 CH109 CH14 CH14 K40
    CH15 CH110 CH15 CH15 K39
    CH16 CH111 CH16 CH16 K32
    CH17 CH112 CH17 CH17 K28
    CH18 CH113 CH18 CH18 K24
    CH19 CH114 CH19 CH19 K20
    CH20 CH115 CH20 CH20 K16
    CH21 CH116 CH21 CH21 K11
    CH22 CH117 CH22 CH22 K7
    CH23 CH118 CH23 CH23 K3
    CH24 CH119 CH24 CH24 K52
    CH25 CH120 CH25 CH25 K56
    CH26 CH121 CH26 CH26 K60
    CH27 CH122 CH27 CH27 K64
    CH28 CH123 CH28 CH28 K68
    CH29 CH124 CH29 CH29 K72
    CH30 CH125 CH30 CH30 K76
    CH31 CH126 CH31 CH31 K80
    CH32 CH127 CH32 CH32 K84
    CH33 CH128 CH33 CH33 K87
    CH34 CH129 CH34 CH34 K91
    CH35 CH130 CH35 CH35 K95
    CH36 CH131 CH36 CH36 K2
    CH37 CH132 CH37 CH37 K6
    CH38 CH133 CH38 CH38 K10
    CH39 CH134 CH39 CH39 K14
    CH40 CH135 CH40 CH40 K19
    CH41 CH136 CH41 CH41 K23
    CH42 CH137 CH42 CH42 K27
    CH43 CH138 CH43 CH43 K31
    CH44 CH139 CH44 CH44 K35
    CH45 CH140 CH45 CH45 K38
    CH46 CH141 CH46 CH46 K43
    CH47 CH142 CH47 CH47 K46
    CH48 CH143 CH48 CH48 K96
    CH49 CH144 CH49 CH49 K92
    CH50 CH145 CH50 CH50 K88
    CH51 CH146 CH51 CH51 K83
    CH52 CH147 CH52 CH52 K79
    CH53 CH148 CH53 CH53 K75
    CH54 CH149 CH54 CH54 K71
    CH55 CH150 CH55 CH55 K67
    CH56 CH151 CH56 CH56 K63
    CH57 CH152 CH57 CH57 K59
    CH58 CH153 CH58 CH58 K55
    CH59 CH154 CH59 CH59 K51
    CH60 CH155 CH60 CH60 K45
    CH61 CH156 CH61 CH61 K42
    CH62 CH157 CH62 CH62 K37
    CH63 CH158 CH63 CH63 K34
    CH64 CH159 CH64 CH64 K30
    CH65 CH160 CH65 CH65 K26
    CH66 CH161 CH66 CH66 K22
    CH67 CH162 CH67 CH67 K18
    CH68 CH163 CH68 CH68 K13
    CH69 CH164 CH69 CH69 K9
    CH70 CH165 CH70 CH70 K5
    CH71 CH166 CH71 CH71 K1
    CH72 CH167 CH72 CH72 K50
    CH73 CH168 CH73 CH73 K54
    CH74 CH169 CH74 CH74 K58
    CH75 CH170 CH75 CH75 K62
    CH76 CH170 CH76 CH76 K66
    CH77 CH172 CH77 CH77 K70
    CH78 CH173 CH78 CH78 K74
    CH79 CH174 CH79 CH79 K78
    CH80 CH175 CH80 CH80 K82
    CH81 CH176 CH81 CH81 K86
    CH82 CH177 CH82 CH82 K90
    CH83 CH178 CH83 CH83 K94
    CH84 CH179 CH84 CH84 K0
    CH85 CH180 CH85 CH85 K4
    CH86 CH181 CH86 CH86 K8
    CH87 CH182 CH87 CH87 K12
    CH88 CH183 CH88 CH88 K17
    CH89 CH184 CH89 CH89 K21
    CH90 CH185 CH90 CH90 K25
    CH91 CH186 CH91 CH91 K29
    CH92 CH187 CH92 CH92 K33
    CH93 CH188 CH93 CH93 K36
    CH94 CH189 CH94 CH94 K41
    CH190 CH193 CH95 K48
    CH191 CH194 CH96 K49
    CH192 CH195 CH97 K98
    COM Relay K15
    HVAB Relay K99

Replace the Relay

Make sure you have the following:

  • Temperature-regulated soldering iron set to 300 °C
  • 60/40 Lead/Tin solder (flux core)
  • Solder wick
  • Fine pick
  • Isopropyl alcohol
  • Cotton swabs

If you have a surface mount rework station, replace the relay as you would any other surface mount part. Otherwise, complete the following steps to replace the relay:

  1. Use the soldering iron and solder wick to remove as much solder from the relay pads as possible. Do not leave the soldering iron on any lead for more than 5 seconds.
    Note  If it is necessary to reapply the soldering iron to the pad, allow the connection to cool completely before reapplying the soldering iron.
  2. Apply heat to the pads one at a time, and use the pick to gently pry the relay pins from the pads. Make sure that the solder is molten before prying.
    Caution  Using excessive force on a soldered pad can result in lifting the PCB trace and ruining the daughterboard.
  3. Remove the relay.
  4. Clean the pads with isopropyl alcohol and cotton swabs.
  5. Place the new relay on the PCB pads and solder.
  6. Remove the excess flux with isopropyl alcohol and cotton swabs.
    Caution  Do not use flux remover to clean the board after relay replacement.

Reassemble the Module


Complete the Disassemble the Module steps in reverse order to reassemble your module.

Tip  In NI-SWITCH 3.1 or later, you can use the Switch Soft Front panel to reset the relay count after you have replaced a failed relay.