i seem to get frequent "service cannot be found", i thought it may have been image independant but i was getting the same on other images. if i channel hop and find a channel which is working then all the other channels start working again....strange!

Does anybody know why it does this?

Sounds like a signal problem mate,
Whats your readings like?

What Image are you using mate I had the same problem using Gemini Image.

tried them all dw 2, ds 3.5, latest gemini etc. i get 94-96% depending on the channel....if it was a signal problem surely it shoudlnt work full stop?

I was getting similar with an Envision 500c (dreambox clone) that I was setting up for the mother in law, eventually it wouldnt clear on any channel, so I put it down to a flakey tuner. I know it wasnt a signal problem as I was using a 500c at the time, no problem at all.
I also had this on another 500c, but the strength only ever showed in the 60's-70's, so I'm sure that tuner had also gone.

That signal reading should be alright,is the BER reading high by any chance?
Had that problem on two boxes here and it turned out to be bad connections and cheap splitter.

might be your tuners weak u tried boosters m8 .

60-70% the box will not lock to any chan, i had box with sinilar prob

I've had the same problem with my 500C under various images, but only when I turn it off with the remote. Turning it back on, it takes several channel switches until one comes in, then they all work again. It's never happened while actually running the box though...