The look of a power's supply is the use of an oscope. The replacement of caps is a good start. Many times; a tuner has gone bad instead; however; also requiring an oscope and bench. Or, the same problem can be caused by a bad connector; a couple of drops of water in the cable serving; or the switch port; or the splitter port; serving the receiver; AND even a bee's nest in the feedhorn throat being built right now!too. Good luck, it really is not an easy chore; and in the old day's there were only a few who could get it right; all the time (but never every time). Slippage is the other problem in electronic repair... i have a few....good luck! Replacing all outside connectors first; then replace the lnb; or the lnbf (we already know they are ok, however; but still can have the culprit in it (grenlin's are very bad problems)); then re-place the splitter after checking it; (change the two ports around after fe-placing the connectors;; you must be using a splitter with an lnb for 2 receivers; or switched using dual lnbf; then change the connectors outside and hook it up backwards (switching which port serves all the different receivers); and the ports for each, switch them to see if they are the cause.
Electronic repair; for a 410 will be much easier than soldering on many of any of the new boards; as manufacturing is reallllllllllly small now. In synchro with the rest of the story; is the list of what you can do that also may be the problem, itself.
For installation perfection; i have grease i use on final; for water/corrosiveness goes away and almost 10 years; a connector will last.
For tightness of the connection; so it won't wiggle; i use the technique of the ages; full on power until tight, then as much strength as i can amass more.
For parts protection; the ground is a real chore; and required for it to work; at all; ever.