Weird DM500 problem

So got a DM500 with a weird problem...Happens on different images ie Pli, Open Pli, Sif. Happens on different sets of bouquets, happens when I bruteforce scan. Happens regardless of whether CAM is in use or not...

Basically I can flash the box no issues,bouquets,cams all fine. I'll flick through say 4 -5 channels and then the channels just black even FTA ones. Or say I can leave it on Sly 1 for 5 minutes then flick the Sly 2 and then back to Sly 1 and it will be be black. It's not the share and not the satellite signal.

Any ideas... It's driving me fookin insane!!!

You could also try to enable 'fast zapping' (Expert Setup).

Yeh tried that but to no avail... I'm wondering if it's the tuner but then as soon as box is rebooted it picks up channel again!

try a better power supply

some times it can cause problems like this

failing that then id think the tuners going or maybe a cap in the box which supplys tuner??

So I've narrowed it down to this...

If I leave it on FTA channels only it works fine... The problem arises when I flick to a channel that requires a CAM to open ie Sly 1. Now regardless of whether CAM is installed and channel clears OR no CAM is installed and I get a black screen as soon as I go back to a FTA channel I get nothing. Signal is still showing 98%, AGC fine and no BER...

So it seems to be a CAM issue although it occurs regardless of whether a CAM is installed... It's almost like the box knows it's a prem channel lol...

Any ideas now?