galaxy 99v - fading ssb carrier

[space cowboy]

it's actually a clone, northstar dx990v.
key up on ssb and there's a carrier. I tried adjusting vr-7 on usb (mic gain down all the way) and it disappeared. switch to lsb and it's back. adjust vr-7 again, the carrier disappears. check usb...
after 4 or 5 switch backs vr-7 doesn't do anything. I fiddle with the mic gain and it slowly starts dropping. 3 or 4 seconds to no carrier and functioning properly.
key down than up, lower carrier that lasts a second and slow drops to 0. longer wait and the carrier last a couple seconds and fades to 0.

another radio that needs new caps?

back of the line.
it's a tie. 3 radios needing caps, 3 working.

 

[9C1Driver]

Are you running a power mic? Some times with a power mic background room noise will look like a slight carrier on a watt meter. However, in this case since you backed the mic gain all the way down it might be tech time.

 

[space cowboy]

astatic road devil. I turned that all the way down too, even though I have checked and no mod gets through with the mic gain all the way down.

 

[Robb]

The carrier balance VR pot may be dirty or faulty, or even have bad solder joints.

 

[AudioShockwav]

I tried adjusting vr-7 on usb (mic gain down all the way) and it disappeared. switch to lsb and it's back. adjust vr-7 again, the carrier disappears. check usb...

I am not familiar with that radio, but the way to set carrier balance on SSB is to adjust it for Minimum on USB and LSB......
Really need a service manual.


73
Jeff

 

[Captain Kilowatt]

X10 on the service manual.

 

[Robb]

Although my DX99 doesn't have this problem, yours might. I've read that there can be oscillation in the mic circuit which can also be misread as a carrier in older models. If you look online for fixes, you will find it. IIRC, a disc cap may need to be added to the mic circuit to keep stray RF from getting in.

Try it with a stock mic yet? Could also be a poor ground connection on the mic, so check the plug on the mic for decent solder joints and no frayed wires.

Doubt that it is a cap problem.