OpenGD77

It could be the microphone socket has failed when you plugged in the programming cable to do the update and the internal microphone is no longer connected.
If you have an external speaker / microphone then try that.

Sounds like a hardware failure.

Bad external speaker jack, try with an external speaker. This is a known failure point.
Broken speaker cable or connector.
Bad connection on front panel ribbon cable.

Colin G4EML

Yes, there was a rounding bug in a previous CPS but that was fixed a few weeks back.

The two columns on the left of the screen show two different things. The first column is a count of the total number of channels used. The second column is the actual channel location used. It is possible (and normal) to have gaps in the channel numbers used. In your example the 634th channel is in ...

It does not matter what firmware is loaded to your radio. The merge is done in the CPS before it is downloaded and this only works with the stated firmware version. You never need to load that version into your radio, it is only needed by the CPS. If you follow the installation procedures completely...

Have you loaded the OpenGD77 firmware into the radio from the extras/firmware loader menu as detailed in the instructions?
The Com port will not appear until this has been done. The CPS cannot be used with the original manufacturers firmware.
Loading the firmware does not use the com port.

There are several adverts on AliExpress for the '10W' version. Some even have a video showing the output power being tested with a low quality power meter. The strange thing is the power is showing as about 6W. So even their own advertising is contradicting itself. I think it is safe to say the 'Plu...

Hold down SK2 when powering on.

Unfortunately the companies making and selling all of these radios don't design them or even write the firmware. As far as we know they buy it in from a mystery third party supplier who seems to be very secretive.

Rumor is that it is actually receiving DSBSC not USBSC so doesn't care if it's USB or LSB but obviously will crap out on a CB channel with both. One firmware claims to be able to transmit DSBSC :shock: Yes it is DSB, it is just using the baseband zero IF signal and the LO leakage provides the BFO. ...