cobra 29 tx one channel off

[frogman296]

i have a friend...called me today...

he travels in sort of a convoy with other trucks...

and today, he said he had to be one channel away from the channel his friends were on so he could talk to them...

the radio worked perfect all along...

any ideas????

i haven't had this happen to my radios before...i'm lost..

[Smitty]

Sounds to me like he's got a radio that's got a 10Khz slide on it. What kind of radio is he using?

[frogman296]

its a cobra 29...stock radio

[Smitty]

oh ok, lol. I should have noticed the topic title, lol

Sorry

[frogman296]

oh ok, lol. I should have noticed the topic title, lol

Sorry

[RedEye]

I had a 29 with a very similar problem, (Once again, Rick save the day with mine...) On the bottom of the radio (Foil side) there is a small black surface mount cap that had cracked. (under L24) I was able to bring it back with ceramic caps. See the topic line below.... pictures and info are there! 73's

http://www.radiomods.co.nz/forum/viewtopic.php?t=1665

[Rick]

Check Pin 22 on the PLL, on channel 1 it should be 0.91 MHz in RX and 1.365 MHz in TX, channel 40 RX is 1.35 MHz and 1.805 MHz in TX, if they are wrong check around the xtal X1. My diagram may help.

http://www.cbtricks.com/radios/cobra/29 ... ic_sch.pdf

[frogman296]

I had a 29 with a very similar problem, (Once again, Rick save the day with mine...) On the bottom of the radio (Foil side) there is a small black surface mount cap that had cracked. (under L24) I was able to bring it back with ceramic caps. See the topic line below.... pictures and info are there! 73's

http://www.radiomods.co.nz/forum/viewtopic.php?t=1665

mine has none there at all, the bottom of the board has nothing in that area .... it is a 29 NWST

[frogman296]

THIS IS THE CLOSEST I COULD FIND...THE BOTTOM OF THE TOP PIC IS TOWARD THE FRONT OF THE RADIO...

THE BOTTOM PIC, BOTTOMRIGHT CORNER IS TOWARD THE FRONT OF RADIO

[Rick]

You need to check the frequency as per my last message.

The part you are pointing to on you picture is the VCO varicap diode.

The fault is most likely to be around the 10.240 MHz xtal check all the components. With a frequency counter check Pins 12 and 13 it should be at 10.240 MHz ? 5%

If do not have frequency counter it like stubbing around a dark room with no lights on, you may find what you are looking for but you may fall down the black hole.

[frogman296]

i used another radio....and adjusted l24...to get it where the s units were highest (same channel) on a properly working radio.

i tried it this afternoon....and i got a good report..before, this wouldn't have been possible...i know this isn't the best, but it will get my buddy back on the go...