Makie SRM-450 active loudspeaker stop working after short-circuit

[Armand]

In order to change blown blue led I unmounted bass speaker but its wires went together wile powered on. All speaker's lights went of. I first thought was a simple blown fuse. I tried bridging fuse poles with screwdriver but no lights turned on, then I replaced fuse but burned it, seems there is a short circuit somewhere. I visual checked motherboard and found no sights of burning elements. I've got schematics but no idea how to proceed.
Any idea what could go off after all the wrong things I did?
I could manage to change resistors or other elements if properly identified as blown.

Thanks in advance

[Jazz P Bass]

With all due respect, your troubleshooting & repair skills leave a lot to be desired.
I had to read that part about 'shorting the fuse holder with a screw driver twice'.
This Mackie is a serious piece of work.
Meaning it is complicated.
Please take it to a shop.

[Armand]

Hey man you're right I'm a complete nob in this but looking for an expert advice on the possible damage. Thanks

[Jazz P Bass]

First off, it makes absolutely no sense why touching the speaker wires together blew anything up.
At idle, without a signal, there should be no voltage on those leads.
You want 'expert advise' on a very unlikely occurrance?

[Enzo]

The possible damage is destroyed output transistors. But many other things can blow fuses in these. SHorting across a fuse holder is a good way to damage a wounded circuit even further. It isn't that simple though, this amp uses multiple power supply voltages and there are power transistors to switch between them. Those could be damaged as well. The tweeter and woofer have separate power amps in there, the tweeter one is a lot simpler than the woofer, because tweeters need a lot less power. And of course there could have been a failure in the main rectifiers.


There is the SRM450 and the SRM450v2, make sure which one you have.

[Armand]

I just confirm that damage was first produced by touching the speaker wires together with no input signal, the system went off at that point.

[Armand]

Thanks for the advice, I see it could not be a simple thing. Looking for a proper audio technician as Jazz P Bass suggested, your tips could be of help. Is there a specific protocol for testing this device. I've no makie tecnical service near by and I read in other threads that this amp is a bit tricky

Mine is SRM450 no V2, unfortunately made in China and not in Italy.

[J M Fahey]

Looking for a proper audio technician as Jazz P Bass suggested, your tips could be of help. Is there a specific protocol for testing this device. I've no makie tecnical service near by

OK, start by saying *where* on Earth do you live.
This is a worldwide Forum.
Members from Aachen to Zanzibar and anywhere in between.
And yes, unfortunately that's one tricky beast.

[Enzo]

The technical ssuggestions I made are basic standard things to do to any failed amp. Any able technician will know to do these things. If you have no technical help nearby, try contacting Mackie to ask where the nearest service is located. Also, ask your friends in the music business where they find service for similar products.

[Armand]

Enzo thanks a lot.

Nearest Makie service is far from home, I'll check them anyway.