224 Exam Chair Base Function Test and Repair
Base Function Fuses and Connections
This illustration shows only the fuses and connections that affect the Base Up / Down function.
Base Function Components
Risk of electrical shock. Always disconnect chair power for three minutes, allowing capacitance to dissipate prior to servicing the Motor Control PC board.
Anytime an Overtravel Limit Switch is detected open, both Up and Down functions are deactivated.
This illustration shows the Base limit switches, the serviceable components of the Base actuator, and the fuses on the Motor Control PC board. Use the table below to isolate the malfunction.
| Problem | Required Action |
|---|---|
| Motor runs, but makes grinding noise. | Clean / lube actuator threads. Remove any debris from base slides. Do not lubricate base slides. Replace actuator if necessary. |
| Motor runs, but table does not move. | Inspect / replace motor coupler. |
| Motor does not run. | Check Motor Control PC board fuses (F1, F2). |
| Check limit switch wire connections. | |
| Test Limit Switch(es). |
Base Actuator Test
Risk of electrical shock. Always disconnect chair power for three minutes, allowing capacitance to dissipate prior to servicing the Motor Control PC board.
1.Disconnect J2 actuator connection.
2.Set meter to VDC.
3.Place meter probes on outside pins of J2.
4.Activate Base Up / Down using foot control.
| Meter Reading | Required Action |
|---|---|
| 0 VDC | Check fuses. |
| Approx. 48 VDC | Replace actuator. |
Base Actuator Motor Resistance Test
Risk of electrical shock. Always disconnect chair power for three minutes, allowing capacitance to dissipate prior to servicing the Motor Control PC board.
1.Disconnect power to the table.
2.Disconnect back actuator from J2 on PC Board.
3.Set multimeter to ohms to check resistance.
4.Using a multimeter, place meter probes on actuator wires.
| Meter Reading | Required Action |
|---|---|
| 1 - 20 Ohms | Actuator motor is good. |
| OL | Replace actuator motor. |
