Cobra 1000 GTL Help

[Rc123]

I installed a variable deadkey in this cobra 1000. The radio was working good, but blew. I replaced the final and driver, but it’s like I have no adjustment on the variable deadkey. Highest it will go is 3 watts. Went to check the voltage on the final and driver and keyed up is 13.10 (my power supply is at 13.8), but when I modulate it will go to 12.3v on the drive and final. Any ideas?

 

[nomadradio]

Uhh, 45 year-old radio with electrolytic caps beginning to go bad, here and there, maybe?

It has a lot of them in there. And 45 years is catching up with it from the sound of things.

73

 

[Rc123]

Just recapped the radio and
No difference. It will key 4 watts with the variable wide open, and at 12 o’clock on the variable nothing. I would think it would key more than that. Does full output just can’t get no deadkey or should I said a smooth variable.

 

[nomadradio]

It will key 4 watts with the variable wide open, and at 12 o’clock on the variable nothing.

4 Watts is a normal max for that radio. Consider that turned full up, the carrier control still drops a little voltage from the driver. Good chance that the radio's stock hookup would show 4.5 or more. No way to avoid losing some carrier at the 'max' end of the variable control.

Seeing the carrier drop to zero with the control halfway down tells us that the resistance value of the control you're using is too high. Measure the control's resistance at the 12 o'clock position. A control that has a max resistance equal to that will perform more smoothly.

73