Qu-Pac squealingh and freezing

[johnParticipant]

So about two months ago during a soundcheck, our PA speakers made a really loud pop like the board was turned off before the power amps, but our Qu-Pac was still on. however, the Qu-Pac was frozen. Nothing worked. I turned it off and back on and everything went back to normal. About a month ago, the same thing happened during soundcheck, except in addition after the loud “pop” from the speakers, a loud shrill sound was coming from the speakers – not feedback – more like a short audio bit caught in a super fast repeat cycle. I turned everything off and back on and it all worked fine. Then it happened again at a show this past weekend. Also during sound check. I turned it off and back on and everything worked normal until the next to last song of the night 5 hours later and the same thing happened again.

I’ve had my unit for several years.
I’ve been on the earlier 1.9 software version for a while.
I keep it in a rack
I’ve bene using the same Ipad and same router for years
It can’t be a heat issue because it happens during soundcheck early in the night
It has happened at three different venues (two of which have very good, clean power), so I don’t think it’s a venue issue
We use some older power conditioners – maybe they are dying and causing some sort of problem?
Maybe our power amps are crapping out on us?

Anyone have a similar problem? I’ve read some threads about people’s boards freezing, but their audio seems to pass through normally. In my case, it is a show stopping moment, and potentially dangerous for our speakers.
Any help would be appreciated. I did a hard reset of my unit, so maybe that’ll help. I’m concerned it’s a hardware issue…

[DavidCoParticipant]

It would be interesting to know what happens to the meters during the pop. Did you get a look at what happened to them?

DC

[johnParticipant]

DavidCo – Yes, I looked at the front panel and the Main L/R meters hover at about unity. Nothing works on the front panel. I can’t mute anything, turn anything down, or select a channel. As a result, I don’t know what is showing on the individual channels. It’s loud a horrible so I’m scrambling to try to mute it or turn it off. Next time it happens (Gods forbid), I’ll try to check my IPad to see if I can see a problem with a particular channel.

[johnParticipant]

To clarify, I am the sound guy and also the guitarist, so I don’t know what happens to the meters during the loud “pop”. But after it freezes, the meters show a constant level right around unity.

[DavidCoParticipant]

Frozen at unity? If it freezes when it happens, perhaps leave the meters screen displayed when not actively adjusting things. It may or may not carry on working long enough to capture the state of the meters during the pop. It would be useful to know where in the signal chain the pop happens.

DC

[johnParticipant]

Basically, the L/R meters are reading the sound level of the squeal that happens after the loud pop….

[airickessParticipant]

I recommend taking it in to be serviced.

[johnParticipant]

I may have to send it in for servicing, but I was really hoping someone may have run across a similar problem or could help me narrow it down to a hardware or software or external power issue… or something… My concern with just sending it in for repair, is that the unit works fine 99% of a 5 hour show. So there’s a very good chance the tech won’t be able to replicate the problem…

[MarkPAmanParticipant]

No harm in re-installing the firmware &/or doing a full reset of the desk.

I hate these “occasional” problems. I’ve got a light that I’m convinced must know when there’s an audience there, as it only ever miss behaves during a show. I can test it for hours and hours first, then 5 mins into the show it will play up.

[johnParticipant]

I totally agree. Intermittent problems are the worst. I did a hard reset of the unit. I also purchased a new power conditioner and will run all my digital gear through that. If I have no issues the next few shows then “maybe” I’ve solved the problem…whatever the problem is…

[Garie63Participant]

Hello! how is your problem? I’m a little pricked up, I have the mouth of Qu-Pac and Qu-24. Good luck

[johnParticipant]

Just following up on this. At every gig the last few months the PA has made a loud “Pop” either during soundcheck or within the first few songs of the actual show. The board always freezes but sometimes corrects itself. Other times I have to turn the unit off and then back on. Two gigs ago, after the “pop” occurred (during our third song), all of the power amps power-cycled as well. It made me think that maybe we have a faulty power connection somewhere in the chain. I replaces all extension cords, all power cables, and made sure power amps are on a difference circuit from all digital gear. Yet at my gig this past weekend the same damn thing happened again…

So we held a makeshift practice Sunday, used all the PA gear, but I used my old analog Mackie board. I couldn’t replicate the problem. Makes me think it has something to do with the Qu-Pac…except why/how would it cause all our power amps to cycle through their power (turn off and on all by themselves)….?????

I just purchased a new Qu-Pac with a return policy. I’m going to upload all my settings from my current Qu-Pac and use it for the next few shows. If we don’t have the popping problems, then I can safely assume it has something to do with my board….so frustrating…

[robbocurryParticipant]

Hey John,
Just my 2p worth here!
First off I think it needs serviced (no surprise there!) I’ve always been a bit over cautious when it comes to heat build up in my Qupacs. It doesn’t take long from switch on until it is in the 60c range, even with a small fan blowing on the back of it. I recall temps of near 70c without a fan. The point I’m making is that it doesn’t need to be on long before it’s warm enough to expand a dry joint or some other connection inside the unit. If you’ve had it on the road for a while perhaps something has worked loose. I’ve had four QuPacs and two qu24s at my disposal pretty much since they were launched, none has ever missed a beat.

[GigaParticipant]

Wow, those intermittant issues are the worst…

It would almost make you wish we had some sort of event/data logging system on board so you could look back what happened.

From what you’re telling I think I would have followed the same path in troubleshooting. After you’ve had the faulty unit repaired, maybe you could keep it at you rehearselspace to test it thouroughly ?

Good luck !

Giga

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