S40 2006 I.C.E Power Issue

So, having joined the forum years ago when I breifly had an S60 (shortly after moved jobs and had a company car) - I have now joined the

fold again and got an S40 - 2006 model.

This brings me to my first plee for help, and it may be a longish one.

The car is in great condition for age and so far the only issue I've had is with the Infotainment/RTI system. I know that this model had a

few issues with radio's freezing etc but my issue is a little bit different.

So, I have the High Performance system with amp etc in the boot (although I've not seen it yet!!) and also the RTI with flip up screen on

dash etc.

My question is: How connected are these systems, if at all? I have an issue where randomly when listening to radio or CD the system will

turn off for a couple of seconds and then come back on. The screen on the centre console returns breifly to show the temp and fan info and

then it all comes back on a few seconds later and continues where it left off. The screen on the SatNav also turns off and comes back on

at exactly the same time. Once it's tunred off and only the SatNav screen came back on - the CD player refused to come back on (pushing

the power button brought up the high performance log and then it turned back off until the ignition was tunred off and back on).

I don't know if it's just the main unit showing signs of age or whether its more of an electrical/power issue. I am tempted to replace the

unit with the Bluepower but there's no point if it's a electrical/power issue as it will just be the same.

If the RTI and CD/Radio systems are separate then I guess it has to be some common factor such as fuse/wiring/power feed etc. as the screen

turns off and comes back on at exactly the same time as the main unit.

The car is 10 years old so I'm assuming its not firmware/software related as I can't believe previous owners would have just ignored it!!!

On another note - any decent/recommended Volvo Indies/Specialists in the Bournemouth/Poole area that people use????

Cheers.

Any idea's?

Is there a process that runs regularly that could be causing the issue? Like the ECU doing some kind of check?

One thing I noticed yesterday when i was on a longer journey is that this happens about every 15mins, pretty much spot on.

The other thing is that if I shut down the SatNav it doesn't happen as often, however, when it does happen it tends to lose power and then not turn back on, unless I turn off the ignition and turn it back on.