DVDR75/051 No audio from internal TV tuner to scart TV

My out of 1 year warranty DVDR75/051 (receipt was binned) was experiencing the stuck in “dealer/demo” mode so I reflashed the firmware and opened it up to clean the laser lens with isopropanol and cotton buds. The DVDR75 now operates - haven’t put it to standby yet (also changed the Standby setting to “Low Power” as I think the original problem was related to the standby setting going to "Demo mode).

The current problem is that when in Tuner mode the picture is displayed okay but no audio is output to the TV via the scart. The scart connection to the TV is okay as audio is present when a DVD is played. I think I must have unseated a connection ribbon when I was cleaning the laser lens. Anybody have any ideas what I should check is connected correctly? I have the service manual for the DVDR70 and DVDR75/0x1 if that is any help to anyone - it is 29Mb in Winzip format.

Thanks

Just to rule out something as simple as a TV zone issue, I would recommend checking the county setting to make sure that it is set to match your area, since the sound channel carrier frequency varies from one TV format to another, at least with the PAL system. For example, if someone in the UK has their country code set up as Germany, they would likely get the picture tuned in, but without any audio. One other thing to double-check is that you have loaded firmware for your region. For example, Lite-On has different firmware for different countries.

Once you rule out the firmware and zone, I would recommend checking the internal wiring. The TV-Tuner in DVD recorders is usually a separate card connected up with a ribbon cable. The tuner can be located by following where the RF-in connects to on the inside. If this is a small board with a ribbon cable or a set of wires leading off from it, ensure the connectors at both ends are firmly pushed in.