Current software of tata sky facing problem while when we change mpeg4 channel [lcn 993] to mpeg2 channels [any lcn like 100] it appear only black or blue screen but here is exclusive solution on DDF, if you want to change channel then hold channel change button for 5 to 10 sec[5 to 6 channel forward or backward] you will get picture as normal. No need to off or on.