Botex / Stairville dimmer - channels dropping to 80%ish

[pritch]

A while ago, faced with not enough money, and the need to replace our dimmers in a terrible hurry, we bought a load of these:

http://www.thomann.de/gb/stairville_ddx620i_dimmer.htm

 

(Actually, I think they're badged as Botex, but same difference)

 

They're wired for three-phase, and two of them have developed an interesting feature. If any of the channels from 1-4 are at 100%, and you then bring either channel 5 or 6 up to anything over 80% ish, channels 5 and/or 6 will go to 80% and beyond without grumbling, but 1-4 will snap back to what I'd estimate to be around 80%.

 

I'm certain it's not a desk or DMX issue, as it does it from the local control on the front of the dimmer, too. It does it even if there's no load on channels 5 or 6, so bringing up an empty channel will still result in a dip on the other four channels. It seems to be independent of the load on the channel that's dipping - we can have 50W or 2kW on the channel, and the same happens.

 

Anyone seen this before? Any suggestions?

[Gerry]

A while ago, faced with not enough money, and the need to replace our dimmers in a terrible hurry, we bought a load of these:

http://www.thomann.de/gb/stairville_ddx620i_dimmer.htm

Why not contact Thomann for advice?

These units have a 3year warranty.

Cheers

Gerry

[pritch]

Why not contact Thomann for advice?

These units have a 3year warranty.

 

Ultimately, that's what we may end up doing; I was rather hoping that someone here would have experienced this before though, and be able to say "We had that; it was due to xyz being loose", and me being able to open the case, reseat whatever it is, and get it all sorted without having to unwire them, box them up and send them back to Germany.

[musht]

Would look for anything involving the analogue inputs ,even internally as guess local control is on sliders, 5&6 sapping 1thru 4 sounds like an anlogue ground fault.