Korg Forums

Rob Sherratt · Platinum Member Joined: 16 Apr 2007 Posts: 4590

The fateful day was yesterday (Sunday) at an evening performance in a hotel conference room, Pa2x and vocals with harmony in full swing, using a pair of Alesis M1 520 powered speakers.

One of the audience decided we needed more lights on, so hit the switch that turned on 60 flourescent lights in one go - on a single breaker. What a noise it made via the Alesis powered speakers - sounded like a real bad case of fire crackers exploding in time with the flourescent light display. I guess there were over 300 explosions of back-EMF caused by all those flourescent starters firing at the same time, in the space of about 5 seconds.

Then pfutt - no sound at all. Both speakers ruined, and probably my Pa2x as well. So please forgive me if I sound a bit depressed over the next few weeks Smile

rikkisbears

Hi Rob,
hopefully not.
I'd be depressed too. All the best.

miden · Posted: Mon Aug 18, 2008 10:32 pm Post subject:

Rob the power supply has an inline fuse, a fast-blow (well it did on the PA1x from memory) so all may not be lost..Open 'er up and have a look, might be as simple as that...

Dennis

Rob Sherratt · Platinum Member Joined: 16 Apr 2007 Posts: 4590

Hi Dennis,

In my young engineer days, I saw a Honeywell mainframe computer go up in smoke. One of my colleagues turned all the flourescent lights on in the computer hall via a single breaker. The switch mode PSU broke down and applied mains voltage momentarily to the 5v DC rails causing all of the 5v semiconductors to behave briefly like candles. Every chip in every circuit board was fried. That was expensive, well over 2 million to replace the computer.

Anyway, there is no fuse blown in my Pa2x - but it is powering up in an unusual state and some LED's are either blown or the software/ processor is screwed. Both the Alesis speakers are fried.

chuckdelp46 · Joined: 04 Sep 2003 Posts: 44 Location: Danbury CT USA

Rob - I hope someone had insurance. If not, sounds like it could get very expensive for you. What a shame.

dschultze · Full Member Joined: 25 Oct 2005 Posts: 204 Location: UK

Rob - this is terrible news and you have my sympathy. I hope that you can salvage something from this and at least get some of the kit repaired.

You must be mortified. Crying or Very sad

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Cheers

Dave
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Korg PA4X

Rob Sherratt · Platinum Member Joined: 16 Apr 2007 Posts: 4590

I'm following up the insurance questions with the hotel at the moment. Trouble is that here in Greece people solve problems with a shrug of the shoulders, "Avrio" (means tomorrow), and then they walk away. Of course "avrio" is the same answer you get when you see them the next day, and so it goes on.

pcguy · Full Member Joined: 24 Jul 2008 Posts: 122

That's horrible news. But the thing is that , it can happen any time again. I wonder if there's a device that we could hook our keyboards and speakers to. Something that would control the voltage spikes. Many old buildings have these curcuit problems, especially when you try to plug in some many things .

Rob Sherratt · Platinum Member Joined: 16 Apr 2007 Posts: 4590

Apparently the best voltage spike and lightning strike protector on the market is a suitably rated UPS (uninterruptable power supply). These are basically a battery charger driving a big lead acid battery, which then drives an inverter that re-generates a clean mains supply. I wish I had been using one!

Sharp · Posted: Tue Aug 19, 2008 12:33 am Post subject:

Hi Rob.

Sorry to hear that.

I have a quick story for you....... My father saw a guy die on stage over exactly what happened to you. Same story, some idiot turned on a ballroom of lights in one go and there was a loud bang from the PA. The lead singer was stuck to the mic, and was killed by a 2200WATT power amp that travelled through the mixing desk to his face, and down to the ground through his body.

So while I'm sure you feel rather pissed off over what happened, take a moment to consider yourself also lucky mate.

As a rule back when I was gigging 7 nights a week, I always played through a UPS, and the singers used radio mics. My own mic was passed through an 01V that was connected to the same UPS the keyboards where.

In my time gigging I'm happy to say that I have never seen the UPS protecting me from a spike. It was usually always a brownout that it kicked in for.

Take care.
Sharp.
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greenkidd · Joined: 10 May 2007 Posts: 47

miden · Posted: Tue Aug 19, 2008 3:45 am Post subject:

Lika · Posted: Tue Aug 19, 2008 7:00 am Post subject:

Hi Rob .
It is very sad to hearing your story . Smile

Yes here (in Greece) is like that - when you have problems ,they say "Avrio" (tomorrow) ...that's why we have to know what we have to do ...
I will try to help you and all of us for the future ...
First - we have to have with us DI boxes every time ( to avoid noise problems of dimmer lights and so on ...)
Then - in Greece (and I guess not only) very often there is a problem with Ground on Power ... What we do ? - We isolate the Ground on our Power ...
That's all ...
I don't know if I explained well - but I did a try ...

Rob Sherratt · Platinum Member Joined: 16 Apr 2007 Posts: 4590

I think the lesson for me is that I will get a suitable UPS and connect all mains equipment to that. Sharp's tale convinces me further!

PraiseTheLord · Posted: Tue Aug 19, 2008 11:37 am Post subject:

Sorry to hear this, Rob. I would be beside myself.

Doesn't a surge protector help just as well as a UPS, in terms of protection, that is? Naturally, it doesn't provide the back-up power, but the priority is to protect the equipment.

There is usually some insurance offered with the better surge protectors.
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Graham (Pa1000)