KDL-43W809C slow/unresponsive turn on

[MattH42]

Since a recent house move my Bravia Smart TV has become intermittently unresponsive.

It had been sat unused for about 6 months (disconnected, but in protective packaging).  I recommissioned it in my new house and it has been intermittently displaying the following faults:

Try to turn on with remote, no response.

Try to turn on with remote, lights up at the power light, but no picture/sound.

Turns on, but screen stays black and sound is on... sometimes clears itself after 20 to 30 seconds. 

All of the above faults started at the same time.  It's a 4.5 year old TV, but it's actually had very little use.  It's had the latest firmware installed, no faults found when I use the built I troubleshooter.

Any help greatly appreciated.

[rooobb]

Have you checked on the sony web site that the firmware is the latest?

[MattH42]

Yes, I've checked that and it's the latest version

[rooobb]

So you have this version https://www.sony.co.uk/electronics/support/lcd-tvs-android-w75xc_w80xc-series/kdl-43w809c/downloads/... installed just few days before storing it? In that case maybe a factory reset could help