**NOTE 1: The following fix is ONLY applicable to owners of "facelifted" (1994 and 1995 model years) W124 models, with the BE-1492 and 1692 radios.
**NOTE 2: The use of evaporating chemicals is largely illegal/banned in the state of California. If this is the case, and you live in the PRK, you may want to find another suitable chemical contact cleaner that meets your state and local laws.
OVERVIEW/BACKGROUND
A common issue with the Becker BE-1492 (and the follow-on BE-1692) radios that came stock in US-spec E500 and E420 cars, is the gradual loss of volume control with the volume/power knob on the lower left side of the radio's faceplate.
This condition results in the inability to adjust volume, once the situation advances enough. Essentially, this is a design flaw in the choice of component used to control the volume.
The cause of this condition is dirty/oxidized contacts in the control potentiometer. Some recommend sending the radio in to Becker and/or other Becker-capable repair shops for replacement of the potentiometer. However, this is only a fix that will work for a year or two, at best, until the potentiometer's contacts begin oxidizing again.
There is a fairly easy and quick fix to remedy this situation, and it is also inexpensive. If and when the oxidation condition re-appears, the fix can be redone as needed.
MATERIALS/TOOLS REQUIRED
Time required for this job: Approximately 10 minutes
JOB PREPARATION
Here are photos of the required items to perform the job.
PROCEDURE
First, here's a view of the BE-1x92 radio in the dashboard of a W124 model.
The first step is to remove the volume/power knob. This comes straight off with modest effort (and presses back on once the job is complete).
Once the knob is off and the volume potentiometer is exposed, carefully press the end of the flexible length of hose DIRECTLY onto (around) the silver aluminum center. It should stay pressed on enough that you can let go of the hose once it is properly pressed on. Note that the radio may turn on with the pressure; that is fine.
Next, carefully insert the end of the red straw into the upper end of the tube (while it is still pressed onto the potentiometer). Spray out approximately 1/4" of contact cleaner, carefully, into the tube. It will run down to the bottom of the tube.
Once you have sprayed the contact cleaner into the tube, wipe off the end of the tube with your fingers, and blow into the tube with your mouth. This will force the contact cleaner down and into the potentiometer contacts.
After doing this, you may see the red alarm light glow faintly, and/or the radio go on and off as the liquid soaks into the potentiometer contacts. This is ok; the contact cleaner will evaporate fairly quickly.
After blowing, remove the tube from the potentiometer. Using your fingers, or pressing the knob back onto the shaft, work the potentiometer back and forth with your fingers. Rotate it several turns in each direction, back and forth, and do this for a good minute. This action will spread the contact cleaner onto the potentiometer contacts.
After a couple of minutes, the volume knob should be making correct contact with the volume control, and you should find you have perfect or near-perfect control of your volume again.
Enjoy your new-found sound. Repeat as necessary when you begin losing volume control again in the future.
Cheers,
Gerry
**NOTE 2: The use of evaporating chemicals is largely illegal/banned in the state of California. If this is the case, and you live in the PRK, you may want to find another suitable chemical contact cleaner that meets your state and local laws.
OVERVIEW/BACKGROUND
A common issue with the Becker BE-1492 (and the follow-on BE-1692) radios that came stock in US-spec E500 and E420 cars, is the gradual loss of volume control with the volume/power knob on the lower left side of the radio's faceplate.
This condition results in the inability to adjust volume, once the situation advances enough. Essentially, this is a design flaw in the choice of component used to control the volume.
The cause of this condition is dirty/oxidized contacts in the control potentiometer. Some recommend sending the radio in to Becker and/or other Becker-capable repair shops for replacement of the potentiometer. However, this is only a fix that will work for a year or two, at best, until the potentiometer's contacts begin oxidizing again.
There is a fairly easy and quick fix to remedy this situation, and it is also inexpensive. If and when the oxidation condition re-appears, the fix can be redone as needed.
MATERIALS/TOOLS REQUIRED
- Can of electrical contact cleaner (DeOxit brand is preferred, but not required)
- Flexible tube with 1/4" inside diameter (typically 3/8" outside diameter
Time required for this job: Approximately 10 minutes
JOB PREPARATION
- Cut 8-10" length of hose using a pair of ordinary household or shop scissors, or a carpet knife or other sharp cutter
- Prepare can of contact cleaner by inserting red plastic straw into nozzle. This will help direct cleaner where it needs to go during procedure.
Here are photos of the required items to perform the job.
PROCEDURE
First, here's a view of the BE-1x92 radio in the dashboard of a W124 model.
The first step is to remove the volume/power knob. This comes straight off with modest effort (and presses back on once the job is complete).
Once the knob is off and the volume potentiometer is exposed, carefully press the end of the flexible length of hose DIRECTLY onto (around) the silver aluminum center. It should stay pressed on enough that you can let go of the hose once it is properly pressed on. Note that the radio may turn on with the pressure; that is fine.
Next, carefully insert the end of the red straw into the upper end of the tube (while it is still pressed onto the potentiometer). Spray out approximately 1/4" of contact cleaner, carefully, into the tube. It will run down to the bottom of the tube.
Once you have sprayed the contact cleaner into the tube, wipe off the end of the tube with your fingers, and blow into the tube with your mouth. This will force the contact cleaner down and into the potentiometer contacts.
After doing this, you may see the red alarm light glow faintly, and/or the radio go on and off as the liquid soaks into the potentiometer contacts. This is ok; the contact cleaner will evaporate fairly quickly.
After blowing, remove the tube from the potentiometer. Using your fingers, or pressing the knob back onto the shaft, work the potentiometer back and forth with your fingers. Rotate it several turns in each direction, back and forth, and do this for a good minute. This action will spread the contact cleaner onto the potentiometer contacts.
After a couple of minutes, the volume knob should be making correct contact with the volume control, and you should find you have perfect or near-perfect control of your volume again.
Enjoy your new-found sound. Repeat as necessary when you begin losing volume control again in the future.
Cheers,
Gerry
