I want to inform you happily that I succesfully run my Cumulus first time today after months of trials and failures !
Dear friend Steve Marshall sent one of his working Oric Atmos to me and I received my new Atmos and had chance to try it with my cumulus.
In the first trial, something awful happened ! Smokes came out from my PSU unit which is supposed to give power to Atmos and microdisc together.
I don't know much about repairing in electronics and it was a devastating saddness after big enthusiasm to see if new Atmos and cumulus are working fine.
Fortunately my dad managed to mend it like McGyver and replaced all the burned diodes and PSU is recovered.
Then, I run the new Atmos without and with cumulus and this time everything went perfect !
I manage to run many disc images with cumulus and majority of them run perfectly. A few of the images stuck (like manic miner) but its not a problem at all.
So, it is clearly verified that, my own Atmos unit is not compatible with Cumulus maybe due to replaced memory chips. Cumulus is perfectly fine and running without any problem.
Thanks for all of friends here concerning my situation.

This is my perfect Oric setup with Microdisc unit, Cumulus, mp3 media player to play tap files and two beloved Atmos's running Zip-n-zap of Twilighte.. Perhaps its one of my most happy days of my life..