thanks for the suggestions... to both of you.
I haven't used my LT-8700 for sat analog tv since I passed to Digital (10 years now). Since then, the LNB cable has always been disconnected from it, I had only the 4 motor cables attached on it. I kept using it just to have a nice AV channel satellite list on scart n.3, for my positioner ... and this job has always been done greatly by it!
It's been fun in all these years to add new satellites and adjust positions... even recently.
But yes, i'm starting to think that probably a repair it's not even worth. I have found a deal for an Echostar DVR-7000, since when it came out (2001-2002), has been always a dream receiver for me... but it was too expencive to take! We all know that this receiver was a flop... for its price, and its life ended prematurely. But now i got it for a few bucks, and once it arrives here (a matter of days) will be the subsitute of my beloved LT-8700.
I know that actually there are better linux based receivers out there, and I too have a dreambox 7020 since years in another room. But I just wanted something to take the place of the 8700 for the motorized dish room and i'm glad it will be another Echostar
Yeah... time passes for everyone... I will miss my old analog echostar, but it will stay always here, somewhere in my house

and maybe one day I will dedicate some time to take a look at the whole power supply circuit, which scheme i downloaded from this forum (thanks!) and eventually attempt a repair