| Author |
Message |
    
Madman28
| | Posted on Friday, December 13, 2002 - 7:05 am: | 
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I just bought a used cobra 25 classic and went to power it up and all I get is a quick flash of power and then nothing. Only lasts less then one second. It will do it every time I apply juice to it.
Same plug works fine w/ my galaxy
Plenty of power comming into it.
Any thoughts where too start??? |
Taz
| | Posted on Friday, December 13, 2002 - 9:13 am: |
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towards the back, open the case and look for a burnt spot on the board. Find the burnt part and clip it, then replace it asap to protect from future damage to the radio. |
307
| | Posted on Friday, December 13, 2002 - 9:23 am: |
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1) Most likely the 8 volt regulator is going into shutdown caused by a short inside the radio somewhere. The 8 volt regulator will shut down when greater than 1 amp of current is drawn for a certain period of time..Good luck..
2)I have seen this a million times...The "power switch" in the radio is bad. Apply power then short the power switch and see if the radio comes back on..I bet it will..Let us know. The power switch get dirty and will not supply "current"..
307 |
Madman28
| | Posted on Friday, December 13, 2002 - 2:20 pm: |
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Nice call 307 it is the power switch.
Can the switch be cleaned? or do I need to replace it?
Thanks in advance |
307
| | Posted on Friday, December 13, 2002 - 5:03 pm: |
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You must replace it...
307 |
Chris
| | Posted on Friday, December 13, 2002 - 11:15 pm: |
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I have bought a Cobra 25 Nw-St and it will not power up either. With everything off. I plug the radio into the power supply and turn on the power supply, the radio is off now, and before I can turn the radio on it trips my power supply. I put a ohm meter across the postive and negative leads on the radio and i get continuity, so this is telling me I have a short somewhere. Does any one have a clue where?? Nothing on the board looks discolored or crossed over. Thanks for any input...
Chris in AZ |
Chris
| | Posted on Saturday, December 14, 2002 - 3:48 am: |
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Would this be the polarity diode? |
KGC755
| | Posted on Saturday, December 14, 2002 - 1:00 pm: |
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Chris,
>>>>>all I get is a quick flash of power and then nothing. Only lasts less then one second. It will do it every time I apply juice to it.<<<<<
Not if it powers up even a little bit. If the protection diode is blown it wouldn't power up at all. |
307
| | Posted on Saturday, December 14, 2002 - 8:47 pm: |
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Replace the black diode near the power connector. 1N4003 (Rad Shack)You can use a 1N4001 , 1N4002 OR 1N4003
307 |
Taz
| | Posted on Sunday, December 15, 2002 - 12:03 am: |
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Thats what I did. |
Chris
| | Posted on Sunday, December 15, 2002 - 3:14 pm: |
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Thanks.
Yeah this radio will not even power up. It trips my power supply every time. Thanks for the input and the info on the #'s 307
Chris in AZ |
Mike
| | Posted on Sunday, December 15, 2002 - 3:31 pm: |
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307 Royce 607 won't power up. Can I replace the polarity diode (black diode near the power connector) with a (Rad Shack) IN4001, IN4002 or In4003 as you recommended for the Cobra 25? Inside chassis powerlead (neg)wire was burned and was touching the cap 33MFD 10V CED4W and slightly surface burned it. Seems like a reverse hookup by someone. I bought radio a yard sale. No manual was included. What else should I look for or do. I am handy with electrical/electronic stuff. Mike |
307
| | Posted on Sunday, December 15, 2002 - 7:32 pm: |
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Yep...Same thing...
307 |
Chris
| | Posted on Tuesday, December 17, 2002 - 6:36 pm: |
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Thanks again for all the info.
Replaced the 1N4004 with a new one and it works great.... Thanks, Happy Holidays....
Chris in AZ |
307
| | Posted on Tuesday, December 17, 2002 - 8:06 pm: |
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Anytime!! Glad to see you fixed it!
307 |
popeye5
| | Posted on Thursday, December 19, 2002 - 8:38 am: |
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I have a Cobra 25 Classic which powers up ok but I get no audio. The mike seems to transmit but I have no idea if a signal is going out since I have no audio. The first indication of a problem happen when the unit powered no audio for about 45 minutes and the unit seemed to work ok. This happened three times and then the audio went completely. I have installed other units and the antenna works fine. Any suggestions? |
307
| | Posted on Thursday, December 19, 2002 - 12:25 pm: |
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If the "S" meter works and you can't hear , check the speaker , if it is ok , replace the Audio IC....
307 |
bruce
| | Posted on Thursday, December 19, 2002 - 10:38 pm: |
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popeye i had one and 307 is correct in my case the audio chip DIED. |
Mike
| | Posted on Friday, December 20, 2002 - 12:43 am: |
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307
You were right again!
I Replaced the polarity diode (with IN4004) on the Royce 607. Powered right up. Thank you for the advice on replacing it. The radio transmits ok but has no rx. Have checked the mic, speaker, etc. S-meter has no readout...What else should I check or followup with besides Audio IC ...Thanks 307 MIKE |
