It looks like I found solution for this issue. First I spent few hours on the roof experimenting with cables, switches, new linear LNB and everything was working same way as before. I changed all cables, even 50 foot cable from dish to receiver and nothing. I tried new linear LNB and there was no signal.
Then I decided to give another try with satellite
signal finder. I found closest circular satellite to AMC5 which is linear and it's also true south from my location. When I found good signal on that circular bird I moved the dish just few degrees using receiver and pointed the dish somewhere to AMC5. Then i connected satellite finder just to linear output on
Invacom, located that linear satellite and fine tuned the dish elevation and position. Then I connected again everything same way as it was before.
When I went down home i discover that I have 30% signal on AMC5! Wow... Then I went on the roof again and turned the dish slowly using buttons on motor so that dish is in perfect alignment with motor. I was turning the dish just for a small step to left and then I will turn whole assembly (motor+dish) on the pole to the right watching all the time signal meter in order not to lose AMC5.
Finally I had motor and dish straight and pointing directly to AMC5. I finally aligned whole assembly to true south. I also made small dish elevation adjustments in order to hit that linear bird and find good signal. I have to say that this $15 satellite finder is GOLDEN tool. Don't think, just buy this huge time savers!
Then I went home again and I had 60% quality on AMC5. Also I found all other linear and circular birds from 61 to 148. Only problem is that all circular satellites have 90+ quality and strongest signal on linear is 60. I suppose that I should make more adjustments but I will leave that for tomorrow or maybe some other time since I'm more that happy at this moment that my equipment is not faulty.
So, as a conclusion, it looks like that if you have 99% quality on circular satellite that doesn't mean that you pointed your dish good for linear satellite. You have to make more adjustment in dish & motor elevation. You have to experiment and have a LOT of patience.
Thank you all for your suggestions and help in this adventure. I hope that my story will help someone with similar issue.
Regards,
G