Difficulty

Easy

Steps

3

Time Required

                          20 minutes

Sections

1

  • Triac Variable Speed Motor Control (BT136) Repair
  • 3 steps

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  • BackTriac Variable Speed Motor Control (BT136)

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Introduction

What you need

Step 1

              Trouble Shooting (is it really broken)
  • Open the appliance far enough so that the output leads from the controller board are visible leading to the motor. Determine that a Triac is present on the PC board.
  • Using a VOM, test for voltage across the motor on the output of the controller board. The voltage should range from about the same as the voltage at the wall socket at its maximum and zero when the device is turned off. From “off” to maximum the voltage should increase with increase in the position of the speed selector.
  • If the BT136 triac is present on the PC board AND there is no voltage present across the motor connections in any any position of the selector… The problem is almost always a problem with the triac.

Open the appliance far enough so that the output leads from the controller board are visible leading to the motor. Determine that a Triac is present on the PC board.

Using a VOM, test for voltage across the motor on the output of the controller board. The voltage should range from about the same as the voltage at the wall socket at its maximum and zero when the device is turned off. From “off” to maximum the voltage should increase with increase in the position of the speed selector.

If the BT136 triac is present on the PC board AND there is no voltage present across the motor connections in any any position of the selector… The problem is almost always a problem with the triac.

1024

Step 2

              Remove the dead triac
  • Remove the PC board from the device.
  • Set the board up in a clamp, vice or alligator clips to keep it stationary while you work.
  • Note the orientation of the existing triac before you remove it.
  • De-solder and remove the triac and wick out any solder in the contact points.
  • Clean the flux and solder bits from the PC board taking care not to damage any of the components, traces or mounting points. A soft bristled toothbrush and rubbing alcohol work well.

Remove the PC board from the device.

Set the board up in a clamp, vice or alligator clips to keep it stationary while you work.

Note the orientation of the existing triac before you remove it.

De-solder and remove the triac and wick out any solder in the contact points.

Clean the flux and solder bits from the PC board taking care not to damage any of the components, traces or mounting points. A soft bristled toothbrush and rubbing alcohol work well.

Step 3

              To Hack, or Not to Hack
  • This step is optional… You may wish to fix the underlying problem to prevent future overheating.
  • Using scissors or sheetmetal shears, cut a few strips of stout aluminum foil about 3/8" (about 1 cm).

This step is optional… You may wish to fix the underlying problem to prevent future overheating.

Using scissors or sheetmetal shears, cut a few strips of stout aluminum foil about 3/8" (about 1 cm).

To reassemble your device, follow these instructions in reverse order.

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Author

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                    Able Baker

Member since: 05/05/2018

149 Reputation

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