Cobra 29 Classic recieve help

#356778

Ok i have a cobra 29 Classic the problem i am having has not happen to me before. It has recieve when i do the talkback mod to it where you jump the EX SP and PA and i can hear truckers talking when going by but they fade away when they get just down the road. When i take the resitor off i dont have any static. the parts i have replaced so far is r 46 and the vr 1 pot i got a voltage chart on the radio and everything checks out that i have checked so far which is tr 23, c 119, r 86, r 94, and c 112 i couldn't find but thats all the stuff the guy on one site said to check that would cause this problem of no recieve im stumped.

73s Wild Aces

#356790

have you tried a good known mic on the radio. the sympton you just described is you get slight receive with the resister across the tb pads and just weak from what you say then remove the resister it does not receive at all. the resister receive jump is normal. make sure the external speaker jack is good by plugging in a external speaker also. also check the caps at the audio chip. C48 is a good one to cause this.

#356791

I have checked the EX SP jack and it works tested PA and it works wired the mic myself so i know they ant any flaws there.

#356797

check the caps at the audio chip also. as I stated C48 can go bad and kill the receive also.
forgot to ask when in receive mode does the S meter move as if it is receiving just no audio.

#356798

ya the s meter moves

#356800

just to check some thing that has me stumped. unplug the mic and jumper pins 1 and 4 on the radio and see if you get receive from the radio.be careful and do not touch the plug case when you do it.

#356802

i changed c-48 and still same problem or it could be bad to its outta parts radio so ill get some new ones

#356814

did you jumper the 2 mic pins to see if you get receive back? it is bugging me that with a resister in place for talkback you get receive. pins 1 and 4.

#356850

yep jumped them without mic and still nothing

#356853

you said that you have receive by jumping the 2 pads for talkback. is this right. if so look at the wires on the back of the mic plug and see if they are all connected as they should be. have seen one of the wires inside the radio come loose and lose some of the functions. let me know and I will check components in the mic circuit on the board for receive if you do not find a loose connection.
also check where the wires hook to the circuit board. have seen them loose at the main board cause this.

#356855

yes thats what i said sonoma its got me stumped as to wat can be wrong with it

#356856

ok sonoma i jumped the 2 solder points on the back of the board and i could hear a slight change in the receive so i unsoldered the resistor for talkback and bam i still have receive but still when they get about to the next hill i cant hear them i lose them if you know what i mean the radio has no ears so im gonna take the end back of this mic put a new cord on it

CB Radio Talk

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