Martin Aura repair

[sleah]

Rigging for a show at the weekend and two Auras died 😒

I think the surge protectors have blown. They are a small round(ish) blue component close to the power inlet on the pcb that are now split and seem to be putting a dead short on the mains. I haven't had chance to unsolder one yet to see if it is them causing the short, but I'm betting they are.

I think it happened when I powered the system. A load of LED and a couple of generics on Chilli bypass dimmers. I used the large breaker on the Chilli to power up and it is real stiff and slow to move. A couple of individual channel breakers went at the same time as well as a couple of halogens blown that were tested before being rigged, so I suspect there was some nasty arcing and surging going on as I moved the breaker.

Lesson learned not to use the main breaker on the Chilli's....

Is it likely the failure mode of the surge protector is to short in order to protect the rest of the pcb or is it possible the pcb is fried? Anyone happen to know what spec the component is so I can try replacing it myself?

Am I talking complete clap-trap? 🤔

Edited February 7, 2022 by sleah

[KevinE]

probably varistors, (MOV's). Their job is not to go short but to 'absorb' transient overvoltage spikes, however they have their limits and will split or go short if they do fail due to such overload. Hopefully that will be the only problem and they can be replaced (typically a 230VAC fixture will use 275VAC rated varistors) but do make sure that's what they are and not something like an X or Y class suppression capacitor. Replace like for like!

The last time I had some little roundish blue things fail in a Martin was in a MAC and they were capacitors in the electronic ballast. The IGBTs in the PFC circuit had also failed.

[indyld]

MOVs can fail with the magic smoke when in power supplies. It's their final protection throw of the dice and, as you suggest, short the supply out if across L/N and take out the trip and internal fuses. I would agree that the best way forward is to desolder them then see evaluate again to if the short still exists (both sides of the MOV. As K says, check that they weren't actually little blue capacitors if there are markings on the board (or check on a non-damaged one.)

Edited February 7, 2022 by indyld