you will need to switch off the main switch near your setup box.
ensure all switch is "off", wait for 5 seconds, than switch on the "Switch (where the HD Box is connected too).
Now check all signal light is on.
Switch on your TV, there should be sound for all channels, therefore,
if this still does work, called 1633
1) ensure TV and STB not muted
2) reboot from main power for both STB and TV if you are using HDMI cable. (reconnect hdmi cable while power off)
3) ensure whilte and red code colour cable are properly connected if you are using either composite and/or component cable.
4) test connecttion direct from STB to TV if you are using any 3rd party sound system.
5) lastly, turn off dobly digital under general setting of the STB.
As you stated that that no sound for all channels of the STB, right.
This could be due to signal issue in the Audio of the cable and/or audio from the STB.
You need to remember to switch OFF the STB and TV &or other devices, before doing the cable connections.
This test is to check on the Audio output from the STB. It is best to test using only 1 Audio output.
When doing any connection, please switch OFF both STB and TV (& other device, if any).
Do not use any existing AV cables between TV and STB, as it could be the problem.
Depend on what type of cable connection between STB and TV.
If you are using HDMI cable, remove it first. As Audio & Video signal are inside the single HDMI cable.
If you are using AV cable between TV and STB, remove it. Take note not to use that TV Input for AV cables, and not to use that AV cable to do testing.
There are 2 or 3 option of AV Ouput of the STB.
If you have an existing AV connection for another 'working' device (DVD player), then use that AV cable as it have no issue on audio. Just remove the AV cable from the DVD player and connect to any one of the AV Output of the STB. Switch ON and test.
If this test do have the audio sound, then the existing AV &or HDMI cable may be the problem.
If still no sound, do the same test on the other AV Output of STB.
If there is no other device using AV cables, then you need to find or get one set AV cables.
Do the test as similar to above procedure.
If there is still no audio, then the problem is the STB audio issue.
This will confirm it is not the cable issue, but due to the STB.
Bring to any Starhub Branch to get Free replacement STB.