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Re: Motorola Radios

To: Thomas Wiencek <wiencek@anl.gov>
Subject: Re: Motorola Radios
From: Roger Gibbs <rgibbs@pacbell.net>
Date: Tue, 08 May 2001 12:21:16 -0700
Hey Tom,

A few things to think about:

1. Electrolytic capacitors are usually lifetime limited.  A good many are 
probably bad.  If you have a capacitor in series with the output signal (to the 
speaker) this is somthing that I would suspect, although the "click" indicates 
that this is working.

2. The volume control (the potentiometer or "pot") is another suspect part.  
This part works with a metal wiper which runs across a resistive element.  
Without use, oxides will often form which cause problems.

My recommendation is to hook up the radio to 12 volts and try again.  Don't 
worry about getting a radio station just yet, the point here is to get some 
signal (even noise) out the speaker.  Rotate the volume control up and down 
many times.  This sometimes works, and you may hear noise/clicks/hiss. Another 
approach is to open the radio
chassis so that you can spray some contact cleaner into the pot.  But try the 
first appraoch first.  And be careful with contact cleaner, some formulations 
can melt plastics.

Good luck.

-Roger



Thomas Wiencek wrote:

> I have two positive ground Motorola radios.  I hooked them up last night to a 
>battery and neither one worked.  The light came on and the speaker clicked but 
>no sound.  I checked the antenna and it was good.  Any ideas what the problem 
>is?  Is there a part (main transistor on the back of the case?) that usually 
>goes bad.  Thank you.
> Tom

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