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Cobra 148 GTL....Taiwan. Is it a keeper?

Discussion in 'CB Radio Modifications' started by Trailblazer, Oct 15, 2020.

  1. 144inBama

    144inBama Electricity doesn't kill you, ignorance does.

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    cheap, easy insurance that it will continue to work.
    I'd be willing to bet, as learned here, the caps are drying out and aren't 100% efficient. The radio is used so he has no first hand knowledge of how it operates after a long conversation, warming/heating up, which is where caps show their weakness and fail. If mine hadn't already been replaced, I was going to recap before installing JUST to make sure at least that those parts wouldn't fail....but I'm just guessing.


     
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  2. sp5it

    sp5it Master of puppets

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    And result is nicely butchered oldtimer.
    You do the same with TV, kitchen radio? Maybe air condition controller?
    Mike
     
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  3. 144inBama

    144inBama Electricity doesn't kill you, ignorance does.

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    So I'm guessing you wait for your engine to start knocking before changing the oil or your tires to blow out before you change them?
     
  4. sp5it

    sp5it Master of puppets

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    Oil is changed on regular basis described in the manual. When tire need to be replaced it is also easy to spot.
    But replacing one working electronic parts with another does not make sense to me.
    I deal with many old radios, I replaced a few capacitors in them, but only defective ones. What can be measured with multimeter.
    Mike
     
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  5. 338_MtRushmore

    338_MtRushmore Sr. Member

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    I recapped my junky 148gtl, but my nice grant xl stays as is. I like tinkering, but I decided I've butchered enough radios and spared the grant. It's been several years and I'm still glad the grant is stock. That's just me though.
     
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  6. 144inBama

    144inBama Electricity doesn't kill you, ignorance does.

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    I really can't argue with what you're saying, but I do own a Capacitance meter that is solely for measuring capacitors. I also do not see how replacing caps is "butchering" a radio? I have it to talk on, I put it back to as close to stock as possible when I got it, no mods, no clipped diodes or resistors, except TR24 and no one has said if I need it back or not. In my field, we replace old parts before they fail, thus preventing a failure of said part during production causing a loss of production. No, this is not the "same" but it is preventing a failure of old parts.
     
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  7. 338_MtRushmore

    338_MtRushmore Sr. Member

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    If you want to recap it, then do so. I recall having the same argument on what it meant to "butcher". Its actually funny now, but my definition has changed. If I had a power supply or something that was known to take out the whole radio when the caps went, I would call that preventative maintenance.

    Just do it
     
  8. nomadradio

    nomadradio Analog Retentive

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    My general rule is governed by cockroach theory.

    If you see one roach out in the open, you can assume there are many more out of sight.

    Until the first one or two electrolytics goes bad, you're right. Nothing broke to fix.

    When the first one or two fails, the rest of the string of dominoes is probably not far behind. You can change them one or a few at a time as they fail. We call that "electronic whack-a-mole". Or all at once. Just a choice.

    There is one capacitor we change on old sold-state radios just to prevent annoyed customers. Once a solid-state radio makes it to 30 or 35 years old we change the audio-chip blocking cap. The one between the chip's output pin and the speaker. Especially if it's rated only for 10 or 12 Volts. If it shorts, kiss the audio chip and your speaker both goodbye. Cheap insurance.

    Since electrolytics often fail when a radio is put back in service after a long shelf nap, this is a legit preventive measure, IMHO.

    73
     
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  9. 543_Dallas

    543_Dallas Sr. Member

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    I would only consider replacing the electrolytics as butchering if the work was sloppy.
     
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  10. Trailblazer

    Trailblazer Supporting Member

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  11. Trailblazer

    Trailblazer Supporting Member

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    Ty for your comment, and there are a couple of factors I am considering .One is because the large cap by the transformer in the rear has a slight bulge on top and the other reason is that it has sat unused for many years. I thought I read somewhere here that capacitors in unused radios "dry out". Ive a bit of time as I am building a modified yagi for some specific objectives, Either way your point is well taken..."if it aint broke...."
    Cheers,
    Rob
     
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  12. Trailblazer

    Trailblazer Supporting Member

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    And your point is well taken and I appreciate the response. I am leaning towards your viewpoint , but will have the kit onhand should I need it.
    cheers,
    Rob
     
  13. Klondike Mike

    Klondike Mike Sr. Member

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    Tokin and Shadetree Mechanic like this.
  14. Klondike Mike

    Klondike Mike Sr. Member

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    Except my kits. I only include various tier 1 manufacturers in my kits. No Chinese counterfeits. Rubycon, Nichicon, Panasonic, MultiComp Pro, etc.

    https://klondikemikescapkits.com/collections/all


     
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  15. nomadradio

    nomadradio Analog Retentive

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    I'll chime in here and confirm my experience with Mike's kits. He uses legitimate-brand parts. No no-name one-lung-sam chinesium. We install several of them a year, and the quality is consistently high. Our customers save a little money with Mike's kits. I stock pretty much whatever we need, but my labor to pull two dozen or more parts from stock costs the customer money, compared to the price of Mike's ready-to-go kit.

    Full replacement of *ALL* the electrolytics has one advantage. You won't be playing "electronic Whack-a-Mole", replacing them one by two as they fail down the road. Once the first one or two goes bad, or looks swollen you know the dominoes have begun to fall. The only question from that point is how quickly they'll quit one by two.

    When the first one fails or looks bad, it's no longer a question of "if", but of when the ball began to roll down the hill.

    73
     
    #30 nomadradio, Oct 27, 2020
    Last edited: Oct 27, 2020

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