problems....any ideas

[S2...RST]

Have a Nokia dbox2, tried loads of different images, was really stuttery and a picture would never come up no matter wot,just squeaks in the background audio wise, so i changed the input amp at the front end of the tuner got the box working(Sportster) with great low BER on most channels, SNR sits at 60k+ and the signal sits aroind the 40k+ region, i can watch the the box but after so long if freezes and there is no response from the remote control or if there is and i try going up or down a channel it just comes up with channel not available,check the streaming info and everything looks fine, turn the box off and those EVIL words appear "error channel not available", waiting on time.so if i leave the box off for couple hours it works again, but after a while(prob under half hour) same thing happens.
Anyone encountered this problem?? I'm thinking power supply side if things maybe component going faulty.
Thanks in advance to anyone with some info on this.
:THANKS:

 

[mgb]

Check the bootlog.
It looks like a dry joint in the SEC chip area.