Sunstrip Active - weird output problem

[indyld]

This is one for the electronics experts out there.

 

Had a Sunstrip Active passed to me recently. Obviously needed one new triac so one was duly fitted. Replacement a success, metered all through, seems good, refit the board. But I'm flummoxed by a new problem, or at least one I didn't notice prior to replacing the triac although to be honest the exact state of the whole fixture beforehand has rather slipped my old and addled mind.

 

Test: Set Sunstrip to FULL in menu, should turn all channels on, and with no lamps connected to the triac board I can see 240v at each of the lamp connections.

 

Connect lamps. Same test, no light, no voltage across the lamp outputs.

 

Check the lamp circuits, all good.

 

Connect 1 or any number of lamps, 240v across any non-loaded outputs on the triac board. Nothing on the loaded ones.

 

I spent some time chasing down neutral connections but didn't find anything amiss, but I really felt like it was gonna be something really obvious like the whole neutral buss was N/C. And yet, I'm still scratching my head with this one to the point where I put it aside to get on with a load of other repairs.

 

Any thoughts? Sunstrip specific or just dimmer related. TIA.

[timsabre]

Sounds like maybe triacs not being driven to on state. You normally measure 240v on an unloaded dimmer whether it's on or off, due to leakage through the snubber.

[indyld]

Sounds like maybe triacs not being driven to on state. You normally measure 240v on an unloaded dimmer whether it's on or off, due to leakage through the snubber.

 

Aha, that may have been the missing piece of knowledge that will help next time I look at it. Obviously the outputs aren't doing anything useful, but the voltage across the terminals caused me some confusion. In that case, a lot of things are still under suspicion including the control circuit. Thanks.

[indyld]

Just to tidy up loose ends here. I got back to this repair today and all the drive side of things seemed fine. In the end, I removed the new triac and the issue went away,thus a different new triac was fitted. Although everything seemed good on the meter following the initial fitting, obviously something was not right with the first one. So, not a re-assembly error as I initially assumed. Edited August 12, 2019 by indyld