Hello all, am a new feller here and am needing/wanting some advice.

I have had the austech DSD 4121 box for about 5-6 years and no problems. About 2 months ago picture started to flicker to a black screen for a few seconds upto maybe 15 seconds then back to picture, it only happened in the morning and came good once the day warmed up. I thought maybe some interference of some kind. It has gotten progressively worse so up onto the roof and I noticed the LNB cover has turned brittle as hell, I touched it and it fell apart. I covered the LNB with a plastic cup to keep the dew out and it sort of worked. I'm replacing LNB tomorrow, my question I have is, the loss of picture occurs only in the morning until it warms up and then starts again in the arvo as it cools down, rest of the day it doesn't flicker at all, does the weather affect a faulty/failing, I'm assuming the old one is faulty/failing LNB?. When I checked the decoder signal strengths I get high 70 to mid 90 signal quality and a constant low 90's to high 90's signal level if those numbers are of any help, it has started to pixalate in the AM and at times goes to a blue screen, box seems to boot, scan and load bouquets with no problems. If the new LNB doesn't fix this what else should I be looking at?. I'm a plug and play kinda guy and not much chop at these sort of things, I didn't know what an LNB was until a couple of weeks ago.

Any responses would be most welcome.
Cheers