Hi,

I have an odd issue with my DM500s and Diseqc.

I have two dishes, one Ku and one C band, both motorised and connected through a diseqc switch. The issue applies equally to both dishes and happens with the C-band dish connected direct, so I'll concentrate on the C-band problem.

In short, the DM500 won't operate the positioner (Moteck) whilst the LNB is connected, disconnecting the LNB results in the positioner working perfectly. I also have very unreliable diseqc switching.

I have put it on my scope and noticed that the diseqc signal is quite under-spec when the LNB loads the receiver.

As a quick solution, I modified the voltage detector circuit it the positioner to detect at approximately 50mv less, which has resolved the issue however, it does mean that I still don't get reliable diseqc switching so isn't a long term solution.

My suspicion is centered in and around DM500 transistor Q71, however I would appreciate any advice from more experienced hands.. Has anyone else seen this issue?