DTi6300 After Crashing While Recording Now Gets Glitchy Picture?

The other night my DTi6300 was recording a programme, after the programme had finished it continued recording, i pulled the plug on the box. Now the picture and sound is all glitchy and the 'no signal sign' appears.

i have reset set the box to its factory settings, and formatted the harddrive i have checked the strength of the signal on the tuners and they are: strength 6 and quality 8;

i have also try using my brothers DTi6300 on the same aerial and there isnt a problem.
there this is not problem with my aerial, as was strongly suggested by topup tvs helpline

has anyone else had this type of problem with there box?