Cobra 148 mark 2

SOURCE: cobra 148 gtl

First take a jumper wire and connect it to the DC Ground of the input of the radio then touch it to the TX pin on the radio if it does keyes up then its in the mic or mic cord on the end of the mic plug or where it goes into the mic cable goes up inside the mic. If the radio don't key up at all then check the main voltage regulator chip one pin will have 8 volts transmit and another pin will have 8volts recieve. If you get no switching DC voltage on the regulator then its bad and needs replacing there is also a known bad capacitor in the radio thats only 10 volts change it to 25 volts at the same capacitance.

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 148 gtl channel mods

contact me i can mod your radio for 65.00

SOURCE: cobra 148 gtl dx manual

This is the Manual for the C148GTL

SOURCE: Installing an Astatic Echo Board in a Cobra 148

There should have been instructions that came with your reverb board. You are going to need to drill another hole in the case of the radio, or find a control where you can install a dual control knob onto.

Your reverb board is likely going to need 8v, so you will need to locate that off the logic board, likely from the frequency synthesizer. The the audio lines from the mic, or the output of mic amp, are going to be redirected to the reverb, and the output of the reverb feed back to where the wires were removed from.

If I recall correctly, the 148 is a bit of a bear to work with, not much room inside. You will likely have to get creative in placement of the reverb board itself. Make sure to wrap well so that it doesn't get tossed around and break something inside.