My Oppo 93 is defective. A mystery...

I have a region free Oppo-93 (previously functioned smoothly) which has troubles after 13 months: it can not play certain blu-rays.
Everything began with a Blu-ray that froze after 12 minutes. I could not play it anymore.
Since then, several BRs falter. Some are recognized as data disc instead of BR, so I can not play them. Another disk says I do not have the latest firmware while I have. Some remain at 0000000 and freeze, others freeze after an hour. DVDs play well..
I have undertaken the following steps on the advice of Oppo (U.S.) and the Dutch seller.
1) erase persistent video data (in flash memory and even tried via USB)
2) Firmware reset
3) re-install the latest firmware - which is only possible through USB and not with CD, as it continues searching.
4) disconnect the power for more than one hour from the outlet and then push 10 seconds on the on/off-button.
5) plug directly into wall outlet and not a box with power strips.
Without result. It improves sometimes for an hour and then it starts again.
The discs make a soft sound as if they are faulty, but when I check them on another player everything is fine.
All advice will be greatly appreciated. Thanks for any help and suggestions.
PS: Oppo UK does not want to help me, because I have a region free player.

Since a week, I also have this strange symptom. When a blu-ray is in in the loader and I start the player, it says
"no disk". After opening and closing the tray, in most cases the blu-ray is recognised, but sometimes they play, sometimes they don't and other times they freeze after approx. an hour.
**********
Mean version BDP9xEU-74-0908
Loader Version: CN0900 8530
Subversion: MCU93-09-0218
chip DC.00.0100
NRD: MRD2.1-MT110304
Edited by Mac Hammer Fan - 1/25/13 at 6:50am

The strange thing is that I don't understand why the optical lens should be cleaned, as I never rent disks and my own disks are clean. They have no fingerprints or scratches and they are immediately put away in their boxes after playing. And why do DVDs play well?

Thanks for your help.

There is no one in my house who smokes. (Never)

I have decided to send the item back to the seller because I still have warranty.
That's the safest solution.
Thanks for every info.
Kind regards
MHF

My Oppo was first sent to the Netherlands where I bought it, and it was a problem on the mainboard. Then it was shipped to a factory in England for repair. Yesterday I received my player and everything goes fine now.
Problem solved.