Strand ACT 6 fault

[Theatermeister]

Hi, I have an ACT 6 dimmer which makes problems, the unit has worked a week without any problem until at the channel 1 at about 50 percent permanently lit. The channel is continuously without any signal at about 50 percent. Does anyone have a solution? I have never had problems with the ACT 6.http://www.blue-room.org.uk/public/style_emoticons/default/sad.gif Greeting: H.-R. Busse

[alistermorton]

Blown triac or do act6 use thyristor pairs?

 

If its blown and conducting on one half of the cycle you'd see it stuck at 50% I'd have thought.

[DrV]

Blown triac or do act6 use thyristor pairs?

 

If its blown and conducting on one half of the cycle you'd see it stuck at 50% I'd have thought.

They use triacs but triacs often go half short. If you put a 100w lamp on it you can just about see the 50Hz flicker

[alistermorton]

Thanks, Dave. I defer to your greater knowledge :-)

 

There could be a fault in the control circuitry of course, but I'd have thought swapping out the triac might be the quickest job before starting to trouble shoot the control logic.

[richardash1981]

Thanks, Dave. I defer to your greater knowledge :-)

 

There could be a fault in the control circuitry of course, but I'd have thought swapping out the triac might be the quickest job before starting to trouble shoot the control logic.

 

The Triacs are fairly easy to replace, because they are off board on flying leads, you just need the right size nut spinner to remove the plate that holds them down. What is even easier to is to cross-patch between the mains channels and the control channels, because each triac has it's own control lead from the main PCB.

 

If you swap the offending triac with it's neighbour, then you will get those two controls crossed between control inputs and mains outputs. If the fault stays on the same mains output, it's with the triac. If the fault stays on the same control input, then it's on the main PCB. At that point you know which end your trouble is!