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The NI SCXI-1169 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 and replace a failed relay.

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 Top cover 2 Relay assembly 3 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

   
   

   Channel Name	Relay Name	Channel Name	Relay Name	Channel Name	Relay Name	Channel Name	Relay Name
   CH0	K0	CH25	K25	CH50	K50	CH75	K75
   CH1	K1	CH26	K26	CH51	K51	CH76	K76
   CH2	K2	CH27	K27	CH52	K52	CH77	K77
   CH3	K3	CH28	K28	CH53	K53	CH78	K78
   CH4	K4	CH29	K29	CH54	K54	CH79	K79
   CH5	K5	CH30	K30	CH55	K55	CH80	K80
   CH6	K6	CH31	K31	CH56	K56	CH81	K81
   CH7	K7	CH32	K32	CH57	K57	CH82	K82
   CH8	K8	CH33	K33	CH58	K58	CH83	K83
   CH9	K9	CH34	K34	CH59	K59	CH84	K84
   CH10	K10	CH35	K35	CH60	K60	CH85	K85
   CH11	K11	CH36	K36	CH61	K61	CH86	K86
   CH12	K12	CH37	K37	CH62	K62	CH87	K87
   CH13	K13	CH38	K38	CH63	K63	CH88	K88
   CH14	K14	CH39	K39	CH64	K64	CH89	K89
   CH15	K15	CH40	K40	CH65	K65	CH90	K90
   CH16	K16	CH41	K41	CH66	K66	CH91	K91
   CH17	K17	CH42	K42	CH67	K67	CH92	K92
   CH18	K18	CH43	K43	CH68	K68	CH93	K93
   CH19	K19	CH44	K44	CH69	K69	CH94	K94
   CH20	K20	CH45	K45	CH70	K70	CH95	K95
   CH21	K21	CH46	K46	CH71	K71	CH96	K96
   CH22	K22	CH47	K47	CH72	K72	CH97	K97
   CH23	K23	CH48	K48	CH73	K73	CH98	K98
   CH24	K24	CH49	K49	CH74	K74	CH99	K99

10. Locate the assembly and serial number labels on the board with the relay you want to replace. White labels indicate the board was assembled using lead solder (Sn 63 Pb 37). Green labels indicate the board was assembled using lead-free solder (Sn 96.5 Ag 3.0 Cu 0.5). Lead-free assemblies have assembly numbers ending in L. The different label types are shown in the following figure.

    

Replace the Relay

Note  NI recommends using lead-free solder for relay replacement on lead-free assemblies, and lead solder for relay replacement on lead assemblies.

Caution  Do not rework lead assemblies using a lead-free work station. Lead solder from the unit could contaminate the station.

Caution  If a lead-free assembly is reworked with lead solder, label the assembly to indicate this condition. This rework can prevent the same unit from being reworked later on a lead-free solder station, because it could contaminate the station.

Make sure you have the following items:

• Temperature-regulated soldering iron set to 316 °C (600 °F) for lead solder rework or 371 °C (700 °F) for lead-free solder rework
• 63/37 Tin/Lead solder (flux core) for lead solder rework
• 96.5/3.0/0.5 Tin/Silver/Copper solder (flux core) for lead-free solder rework
• 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 board.

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. Refer to the Switch Soft Front Panel Help for more information.