Hello,
Latest update: I received new parts an built new shunt regulator board for each of my amps. Also I installed all new Zener diodes. Resistance check was good. I plugged it in - first I saw that still only 2 LEDs lighten up - so I decided that I am having same old problem. But I didn't turned it off right away - and in about 25 - 30 sec other 2 LEDs lighten up too!!! Everything was just fine: voltage check was good, I tuned up hum regulator and connected to my stereo - and music started playing ))). So I guess - the chance is: it was OK in first place, I just didn't wait long enough - I was afraid that LEDs can blow up like first time....
Thanks for your support everybody.
Just one more thing I want to mention: my current speakers KEF iQ30 which sensitivity is 89dB. That is supposed to be not high enough for Paramounts, but I didn't have any problems driving those speakers. Although I already ordered Cain&Cain Abby and waiting for delivery some time soon.
Now I complete full stereo set up: I built Eros, Foreplay III, and now Paramounts )))
Thanks again
Anton