NI PXI-2527 Relay Replacement

The NI PXI-2527 uses electromechanical armature relays.

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

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 PXI chassis.

   Note  Properly grounding yourself prevents damage to your module from electrostatic discharge.

2. Refer to the following figure and table to locate the relay you want to replace.

   NI PXI-2527 Hardware Diagram

   

   Note  Use the numbers printed on the board to verify the revision letter of the NI PXI-2527. (Revision B = ASSY192245B-01; Revision A = ASSY192245A-01.) Use the revision letter to determine the correct reference designator for the relay you want to replace.

   
   

   Relay Name	Reference Designator (Revision B)	Reference Designator (Revision A)
   k0	k0	k33
   k1	k1	k35
   k2	k2	k30
   k3	k3	k38
   k4	k4	k34
   k5	k5	k29
   k6	k6	k25
   k7	k7	k24
   k8	k8	k21
   k9	k9	k20
   k10	k10	k17
   k11	k11	k31
   k12	k12	k16
   k13	k13	k37
   k14	k14	k36
   k15	k15	k26
   k16	k16	k13
   k17	k17	k22
   k18	k18	k6
   k19	k19	k18
   k20	k20	k14
   k21	k21	k11
   k22	k22	k8
   k23	k23	k12
   k24	k24	k9
   k25	k25	k7
   k26	k26	k5
   k27	k27	k10
   k28	k28	k1
   k29	k29	k3
   k30	k30	k4
   k31	k31	k2
   kbc01	k32	k32
   khlselect0	k33	k28
   kref0	k34	k27
   khlselect1	k35	k23
   kref1	k36	k19
   kcjtemp	k37	k15

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.