Composite (CVBS) not working on Q5 Pro

[JBMouse]

Apart from my problems with updating firmware, I also have a problem with the composite out on the Q5 Pro.
Yes, I know it's a rotten picture compared to HDMI, but I am using it with an old tv that only has scart and composite inputs, and, as it's only in the bedroom, mainly used for streaming audio from my PC and internet radio, I can live with the resolution.
Composite is not working on any of the firmwares I can install, up to Android 7, build 2.0.1, and not on Android 5. What am I missing out doing? It should be live all the time I would have expected, so maybe the Q5 is faulty?
I am thinking of getting an adaptor that gets composite from the HDMI port, to see if that works.
Any help appreciated - again!

[futeko.com]

With the box connected by HDMI set resolution to something supported by the composite port (e.g. PAL or NTSC). Now connect by composite cable.

[JBMouse]

Tried, but no luck. Cycled through the modes using the TV Mode button on the remote, (done blind) still nothing.
Because the old composite TV is in another room, I have to diconnect the Q5 from power and move it upstairs, so does removing the power cable to the Q5 reset any of the video settings?
Set the video out to pal, checked it stayed after power disconnect, went upstairs and connected composite, nothing showing. All leads are ok as I have connected another thing that uses composite out, it all works, so I must have a fault with the phono socket.

[JBMouse]

No luck yet, but I do get poor quality sound through the 2 sound phonos when output set to pal or NTSC. Still points to fault with phono socket on Q5. Am waiting for the hdmi to composite adaptor from eBay, which should solve the problem.
Saving up the pennies for a new TV which will solve it!