Copper Talk » Ask The Tech » Radio's Mobile » Cobra 148gtl, no recive audio « Previous Next »

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Bluebird
Intermediate Member
Username: Bluebird

Post Number: 121
Registered: 2-2004


Posted on Thursday, January 07, 2010 - 7:46 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

i have a cobra 148 and there is no recive audio,
i tested the speaker and ext speaker jack, both works fine. tx audio and pa audio is also loud.it recives incoming stations shown on s meter.put your finger on the board around the audio chip and you get sound/hum. put your 2 fingers on the board and you will sometimes hear recive audio. any ideas on what to replace would be a big help. <<<<<<thanks>>>>>>
mitchell
bluebird
cef 398
cvc 113
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Tech833
Moderator
Username: Tech833

Post Number: 1806
Registered: 8-2002
Posted on Friday, January 08, 2010 - 10:54 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

The 148 requires a receive enable contact in the microphone tx-rx switch to enable the speaker audio. Be sure that is connected and working properly. Try another mic if you can borrow one.

Your radio 'Mythbuster' since 1998
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Bluebird
Intermediate Member
Username: Bluebird

Post Number: 123
Registered: 2-2004


Posted on Monday, January 11, 2010 - 1:36 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

yep,, I tryed 2 or 3 mics still nothing??????????
mitchell
bluebird
cef 398
cvc 113
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Bigdadie
New member
Username: Bigdadie

Post Number: 4
Registered: 11-2009
Posted on Monday, January 11, 2010 - 9:16 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Did You check the squelch, or did some one adjust it wrong, inside the radio.
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Bluebird
Intermediate Member
Username: Bluebird

Post Number: 124
Registered: 2-2004


Posted on Wednesday, January 13, 2010 - 9:59 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

YES I ALSO CHECKED THE SQUELCH,, THANKS
mitchell
bluebird
cef 398
cvc 113
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Patzerozero
Senior Member
Username: Patzerozero

Post Number: 4771
Registered: 7-2004


Posted on Wednesday, January 13, 2010 - 8:53 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

'put your 2 fingers on the board and you will sometimes hear recive audio', are you just 'touching' or actually putting pressure on the PC board? if a bit of pressure causes the receive audio to 'pop in & out', then you more then likely have a bad solder joint, or something to that affect, as opposed to a 'bad' part. start touching up the connections with a soldering iron, checking any jumper wires, speaker leads, leads from the jacks to the board, etc......
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Bluebird
Intermediate Member
Username: Bluebird

Post Number: 127
Registered: 2-2004


Posted on Tuesday, January 26, 2010 - 6:22 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

i will do that pat..i am not putting any pressure on the board , just touching it.
mitchell
bluebird
cef 398
cvc 113
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Earl68
New member
Username: Earl68

Post Number: 3
Registered: 1-2012
Posted on Sunday, March 10, 2013 - 6:15 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I have a 148 gtl made in china and it was working fine but now it has no rx audio.The rx led does not even come on and there is no needle movement.The radio has excellent tx and external and pa check out fine.There is a very low sound coming from speaker but it does not get louder when the volume is turned up.Any help would be greatly appreciated!
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Sonoma
Intermediate Member
Username: Sonoma

Post Number: 250
Registered: 11-2001


Posted on Thursday, March 14, 2013 - 3:13 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

have you checked to see if TX is working fine on all channels? could be a resister bad feeding the PLL. check it out.check R130 and see if it is bad.

ACTION: Replace R130, which is located at the left edge of the PCB, near the PLL chip
(IC1, MB8719). Use a 10 ohm 1/2W resistor.

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