I was wondering what L11 does in the cobra 29ltd classic. I was working with some watts and modulation and i tuch 4he screw of L11 withouth knowing what it does. I would like to learn more about radio

SOURCE: radio shack trc-447

According to the service manual for the TRC-447, the only adjustment is for "power" which is #L205. The only other step in the transmitter alignment is for the "S" meter.
On the Cobra, VR4 is AMC, L14,L13,L12 is AM power.

SOURCE: Cobra 29LTD CHROME low tx no mod, rx good low Vol, talkback good

1 why would you change the finals?? Have you checked you antenna? How are your SWR's? Crappy antenna's cause a lot of problems.

Use an external meter to see what the SWR is, and see what the output is PEP. If its low, then there is something wrong. If it is High, change the mic and turn up the dynamic all the way.

Next. Have you been messing around in there?? Tryin to get more wattage? You turned VR4? If you thought you were turning it up by turning it all the way to the right, you turned it all the way down. Turn it all the way to the left.

SOURCE: i want talkback on my cobra 29ltd classic radio

Open the case on your radio. Solder a 100 ohm resistor between the pa jack and ext speaker jack. You can add a switch if you like to turn it on and off. The lower the resistance, the louder the talkback.

Mechanic688

• 204 Answers
• Posted on Oct 31, 2008

SOURCE: Cobra 25 no receive & no modulation

Hello 49er, When you say "no receive", do you mean no sound, or no signal on the meter at all??I'm just grabbing at straws here so bear with me as there can be different problems doing the same thing.If this radio has been tightened up in a bracket, sometimes that will pull the solder legs loose on the audio chip. That could take away the mod. and RX volume. Is the Microphone ok? If the radio has been in storage, the switches and knobs could have dust and dirt in them. How much troubleshooting are you comfortable with?? If your not, then you might need to take it to a good CB Radio Repair shop to have it serviced. That's what I used to do for over 10 years,,, Let me know how your coming along,,, Mechanic

SOURCE: Cobra 29 Ltd

Hi,

Appreciate the direct "Ask Me" again.

The initial posting would still hold true, best would be:

• remove TR18;
• replace 2SC2069 with 2SC1969; and
  
• adjust L12, 13 & 14.