230 Universal Procedures Chair Limit Switch Test and Repair

Limit Switches Location 

230 and 630 Chair Limit Switches Location

Affected Function: Foot Up

The Tilt Limit Switches are part of the actuator, and are not serviceable.

Ritter Models Foot Up Limit Switch Affected Functions: Foot Up

Midmark Models Foot Up Limit Switch Affected Functions: Foot Up

Ritter Models Foot Down Limit Switch Affected Functions: Foot Down

Midmark Models Foot Down Limit Switch Affected Functions: Foot Down and Chair Position Function

The Back Limit Switches are part of the actuator and are not serviceable.

Base Up Limit Switch Affected Function: Base Up

Base Down Limit Switch Affected Functions: Base Down, Home Function and Chair Position Function

230 and 630 Chair Limit Switch PC Board Harness Test

1.Disconnect appropriate harness from main PC board - see illustration

2.Place one meter probe on the common wire - see illustration

3.Place other meter probe on the wire for the appropriate switch - see illustration.

Check switch tripped and untripped.

Normally closed switches untripped or Normally open switches tripped

Meter Reading

Required Action

OL

Perform Limit Switch / Harness Test

Less than 10 Ω

Limit switch / harness OK, Test actuator.

Normally closed switches tripped or Normally open switches untripped

Meter Reading

Required Action

Less than 10 Ω

Perform Limit Switch / Harness Test

OL

Limit switch / harness OK, Test actuator.
Switch  

Base Up

Normally Closed

Base Down

Normally Closed

Back Up

Normally Closed

Back Down

Normally Closed

Tilt Up

Normally Closed

Tilt Down

Normally Closed

Foot Up

Normally Closed

Foot Down

Normally Closed

Pan Limit Switch

Normally Open

This test is for the Foot, Tilt, and Back functions only. For Base function, perform Limit Switch Continuity Test.

230 and 630 Chair Limit Switch Harness Test

1.Unplug the appropriate limit switch harness.

2.Measure continuity,

Meter reading should be

Actuator Full Up

 

White to Black - Open

White to Red - Closed

Actuator Full Down

 

White to Black - Closed

White to Red - Open

Actuator Midway Point

 

White to Black - Closed

White to Red - Closed

The Back and Tilt limit switches are part of the actuator, and are not serviceable.

230 and 630 Chair Limit Switch Continuity Test

1.Tag and disconnect wires from switch.

2.Place one meter probe on COM terminal. Place other probe on the NC or No terminal - depending on the switch.

Check switch tripped and untripped.

Normally Closed switches tripped or Normally Open switches untripped

Meter Reading

Required Action

OL

Switch OK, Replace harness

less than 5 Ω

Replace switch

Normally Closed switches untripped or Normally Open switches tripped

Meter Reading

Required Action

OL

Replace switch

less than 5 Ω

Switch OK, Replace harness