Malaysia Cobra 148 GTL, no TX on ssb

Thanks in advance for reading, and hopefully making some suggestions. I believe the radio is a 1995 year or close to it, with a EPT014810Z board. On side band, (both usb and lsb) it does not swing the meter needle on the radio, nor does it produce any needle swing on the swr/power meter (Radio Shack 21-534) with a loud voice or whistle. In AM mode, there is needle swing on the CB, and on the swr/power meter, AM seems to work as it should. The TX light does change when the mike is keyed...

Malaysia Cobra 148 GTL, no TX on ssb