NI SCXI-1127 Relay Replacement

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NI SCXI-1127 Relay Replacement

The NI SCXI-1127 uses electromechanical armature relays.

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

Relay Manufacturer Part Number
Aromat (NAiS) TXS-2SL-4.5V
NEC/TOKIN EF2-4.5NUX

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 grounding screw from the back of the module.

    1 Grounding screw
    2 Top cover
  3. Carefully remove the top cover of the module using a flathead screwdriver.
  4. Remove the two screws from the back of the module.

    1 Rear screws
  5. Locate the relay you want to replace. Refer to the following figures and table for relay locations.





    Channel
    Name
    Relay
    Name
    CH0, CH32 K2
    CH1, CH33 K3
    CH2, CH34 K1
    CH3, CH35 K4
    CH4, CH36 K11
    CH5, CH37 K10
    CH6, CH38 K12
    CH7, CH39 K13
    CH8, CH40 K18
    CH9, CH41 K19
    CH10, CH42 K20
    CH11, CH43 K21
    CH12, CH44 K25
    CH13, CH45 K26
    CH14, CH46 K27
    CH15, CH47 K28
    CH16, CH48 K32
    CH17, CH49 K31
    CH18, CH50 K29
    CH19, CH51 K30
    CH20, CH52 K35
    CH21, CH53 K36
    CH22, CH54 K33
    CH23, CH55 K34
    CH24, CH56 K37
    CH25, CH57 K38
    CH26, CH58 K39
    CH27, CH59 K40
    CH28, CH60 K44
    CH29, CH61 K43
    CH30, CH62 K41
    CH31, CH63 K42
    BC01 K15
    BC02 K14
    BC23 K22
    HI_SELECT K7
    1WIRE K6
    4W_HVAB_DISC K16
    2W_HVAB_DISC K8
    CJTEMP K5
    AB0 K9
    AB1 K23
    AB2 K17
    AB3 K24

Replace the Relay

Before you begin, make sure you have the following items:

  • 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.