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Message |
    
Rjmg512
New member
Username: Rjmg512
Post Number: 1
Registered: 6-2013
| | Posted on Saturday, May 17, 2014 - 5:55 pm: | 
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I have an older sears roadtalker 40. When I power the radio up, the tx light comes on (even without the mic connected)and I am hearing a lot of noise. I am receiving but not transmitting even though the tx light is on (red). when I key the mic, the meter on the radio doesn't move, but it still shows the strength of the incoming signal. Is the problem with my mic or antenna, or is it something with the radio? |
Tech237
Moderator
Username: Tech237
Post Number: 1785
Registered: 4-2004
| | Posted on Sunday, May 18, 2014 - 8:24 am: |
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I can definitely say, it's not the antenna or mic.
Look at this logically - the antenna has no way of causing the radio to switch to transmit.Secondly if the radio has the TX light on when the mic is NOT connected, that would pretty much eliminate the mic as the problem. So we know,that the problem has to be with the radio itself.
Now as to what, is a little hard to say, but suspects issues with switching circuit. Not knowing that particular model I don't know if it uses a relay or transistors for RX/TX switching, but suspect the latter. if that is the case, you may have a bad transistor or associated resistors.
If you feel comfortable try changing the switching transistor, if not then you have to decide is it worth sending it in for repair or just replacing it.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Milkman21218
Advanced Member
Username: Milkman21218
Post Number: 589
Registered: 1-2004
| | Posted on Monday, May 19, 2014 - 2:29 am: |
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I no this may not be what you want to hear. But the roadtalker has to be about 30 or more years old. (I have one that I got new 1978). It maybe time for a new radio. If the caps dry out the repairs would be much more than another radio.
Izzy
CEF#502
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Press_man
Advanced Member
Username: Press_man
Post Number: 771
Registered: 5-2008
| | Posted on Friday, May 23, 2014 - 5:26 pm: |
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If you're handy with a soldering iron and patient you could replace the electrolytics in the radio but use 25v - 50v caps. A radio that old has a bunch of 10v caps in it. I capped a 934.38270700 SSB RT 40 that would RX but not TX and when finished it was like new. Your results may vary. Questions are, what is the radio worth to you, do you have time and money to spend?
73 Pressman
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