| Author |
Message |
    
Sparkomatic
| | Posted on Sunday, February 09, 2003 - 3:35 pm: | 
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A friend of mine bought a Grant XL at a Pawn Shop and this radio keeps blowing internal and external speakers. It would burn out a speaker and he would replace the speaker..........it would heat up and quit again. the same thing happens with the nice $25 external speakers they burn out.
I put it on my base on a 14 volt powersupply and turned the volume down to nothing and the external speaker magnet will STILL get too hot to touch. The radio talks good and receives fine but the speakers blow.
Speakers blown
1)3 stock in radio types
2)1 texas ranger external
3)1 cobra external
I run my Texas Ranger 296 mobile to the same speaker for 24 hours at a medium volume and the magnet is barely warm.
Are we in the Twilight Zone or what. WE never played the radio volume much higher than medium. |
307
| | Posted on Sunday, February 09, 2003 - 4:53 pm: |
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There is a capacitor ,C-175 that is probably shorted.
307 |
2600
| | Posted on Sunday, February 09, 2003 - 9:19 pm: |
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I'm amazed that the TA7222P audio chip hasn't taken it on the chin, yet. Any time we see that audio chip fail, we replace that capacitor, or the equivalent for that radio, just as cheap insurance. When it shorts, the audio chip usually gets clobbered. This part is placed between the audio output pin of the TA7222 and the 'hot' side of the speaker circuit. When it shorts, the audio chip feeds direct current into the speaker, along with the audio. C175 is there to "block" the direct current, and allow the audio ONLY to reach the speaker.
C175 is a 470 uF electrolytic capacitor, usually 16-Volt rating. A 25-Volt rating is safer for the replacement. When you put it in, the polarity marking on the new part must match the old one. It is located to the rear of the audio chip. The positive side of C175 leads to pin 9 (next-to-rearmost pin) of the TA7222. If it sounds terrible with the new capacitor, it's a sign the TA7222 didn't survive the experience without damage.
73 |
Sparkomatic
| | Posted on Monday, February 10, 2003 - 7:31 am: |
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I'll let him know about C175.........Thanks. If a radio is not used for 10 years or so will that accelerate the death on certain parts. |
Sparkomatic
| | Posted on Monday, February 10, 2003 - 7:55 am: |
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Is this audio chip used for transmit too? |
Sparkomatic
| | Posted on Tuesday, February 11, 2003 - 8:33 pm: |
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Problem was fixed by replacing C175, I guess the audio chip survived.
We appreciate the excellent technical help. Big Bob is now happy with his radio. |
2600
| | Posted on Wednesday, February 12, 2003 - 12:36 am: |
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Way cool!!
Congratulations.
73 |
Bigbob
| | Posted on Wednesday, February 12, 2003 - 8:31 pm: |
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Obviously a different Big Bob maybe I should change my user name to Maddbob like my freinds used to call me when I wasn't so mellow,used to solve all my major problems with black powder,man you should see what happens to a freaking out cobra 29 when you fill it with 2 pounds of black powder and attach a long fuse and light it,POOF absolutely no more problem,ahh those were the days. |
Sparkomatic
| | Posted on Wednesday, February 19, 2003 - 5:14 pm: |
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BigBob you are better off legally just to put the radio on the driveway and run over it with the car. A friend took care of his Cobra 29 Plus in that way when the LEDs starting blanking out. The Cobra Plus series.........what a waste. |
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