623 Exam Table Upholstery Heater System Test and Repair

Use the table below to determine the required action.

Problem Required Action

Upholstery heater does not warm up. Heater switch does not illuminate.

Perform Upholstery PC Board Test

Upholstery heater does not warm up. Heater switch illuminates.

Perform Upholstery Heater Test

Upholstery heater OK. Heater switch does not illuminate.

Replace heater switch.

Upholstery Heater System

Output Voltage Test

1.Disconnect leads to upholstery heater.

2.Set meter to 20 VAC.

3.Place meter probes on leads from upholstery heater PC Board.

4.Press Upholstery (Green) Heater Switch On.

Meter Reading Status Required Action

0 VAC

Thumbs down

Check supply voltage to heater PC Board.

14 VAC +/- 3 VAC

Thumbs down

Check upholstery heater.

Upholstery Heater PC Board Test Upholstery Heater PC Board Test

Caution

Unplug power cord before removing stirrup guide.

1.Remove stirrup guide.

If necessary, remove chair arm Supply Voltage Test brace. Refer to:Table Shroud Removal.

2.Set meter to 200 VAC.

3.Place meter probes on J2 and J3 of Upholstery Heater PCB and plug table into outlet.

Meter Reading Status Required Action

0 VAC

Thumbs down

Check incoming power source to table.

115 VAC

Thumbs down

Check connections and F1 / F2 fuses on PCB.

Upholstery Heater PC Board Replacement

Caution

Unplug power cord before removing PC Board cover.

1.Tag, then disconnect leads to PC board.

2.Depress release on standoffs and remove PC Board.

1.Replace PC Board.

2.Re-connect electrical leads.

Upholstery Heater Test

1.Disconnect leads to upholstery heater.

2.Set meter to 200 .

3.Place meter probes on leads from upholstery heater.

Meter Reading Status Required Action

0 Ω

Thumbs down

Replace Upholstery

3 - 4 Ω

Thumbs down

Check Upholstery Heater Switch.

Upholstery Heater Switch Test

1.Set meter to 200

2.Disconnect Black leads from Switch and insert meter probes.

3.Depress and hold in the Upholstery Heater (Green) Switch

For replacement procedures, Refer to: Heater Switch Replacement in Drawer Heater System

With Switch Tripped
Meter Reading Status Required Action

OL

Thumbs down

Replace switch.

Any resistance reading.

Thumbs down

Switch is good. Perform next check.
With Switch Untripped
Meter Reading Status Required Action

Any resistance reading.

Thumbs down

Replace switch.

OL

Thumbs down

Switch is good. Perform next check.