Am I a failure for not getting it to fail?

[Axtman]

A friend gave me a Powerwerks 100T PA / speaker combo. He said it cuts out on him when he does his singer/songwriter coffee house gigs. Well I have tried everything to get it to fail.

I've pumped lound music through it.
I have left it on for a long time.
I have played guitar through it.
I have used it for vocals.

I can't get the darn thing to fail on me! What should I do?

[The Dude]

Unfortunately, this sort of thing happens. If you're a failure for this situation, I think most techs would also be. The only thing I can think of is that it is being pushed hard and thermalling out. How big are the venues he's playing and how many people? Reading online reviews of the unit, I see that many solo performers are using 2 of them. It's only 100W at 4 ohms and puny little 4.5" speakers. I can't imagine that would cover much of a room. He probably needs another one chained together with this one, or needs to move to something larger.

[g1]

When it's live failure I usually try to simulate 'brown out' conditions with variac. Venues that don't have house PA systems are notorious for poor quality/low AC line voltage.

[Axtman]

The venue he plays in is a small coffee house. The whole place is about the size of a large living room. He does not crank it.

[Chuck H]

You need absolutely complete information about ALL circumstances. I got a call from a livid customer once that insisted that the amp I sold them was cutting out and losing volume at a gig and had to be replaced with the backup amp. Since the backup amp worked the problem was clearly MY amp. What wasn't reported was that along with replacing my amp all other things in the signal chain were omitted to use the backup amp. As it turned out there was a pedal in the signal chain used with my amp that had a dying battery. This was diagnosed and the problem never happened again. But in a recent interaction with this client all that remains in their memory is what they decided happened that night. It was mentioned that the amp I built caused a problem at a gig. They never used my amp as the primary amp after that incident and, in fact, hardly used at all for anything afterward. I took the amp back and refunded the customer. There is nothing wrong with the amp. In fact I'm glad to have it back. But the stain will remain forever even though it's perception and not reality.

My point is... You need to learn what else might be problematic in the signal chain. And it may be confused by circumstances. The 100T may not be the common denominator because something else might be the cause and is only in use when the 100t is. Or at least WAS only in use when the 100T was. Philosophers will state that perception is reality. But that is NOT true. Reality is reality. But good luck convincing anyone with a perception.

[DrGonz78]

Very similar to my post on the Bose L1 thread. It had failed but the fix didn’t make me feel very convinced. I mean I might have reseated a connection that made the problem go away. Or I simply jostled the problem around and it’s still lurking out there waiting to come back. So I got it to stop falling and I tried to jostle it around but it wouldn’t fail. So time will tell if I got lucky. These personal PA systems sure present their fair share of issues. Well hope you get yours to fail so you can get back finding the fault. Although could be a thermal or brown out.

added: have you injected a square wave and check temperature readings? I would think that and some bad house party power are all questions.

[Axtman]

Those puny little speakers put out an AMAZING amount of bass! I was playing Steely Dan's Aja CD through it and had to turn the bass DOWN.

I remember going to a stereo store (remember those?) and I went into the listening room with the salesperson. There was a wall of speakers. I think he was playing Dark Side of the Moon on an album. He asked me to guess which speakers were on. I pointed towards the largest speakers. He then pointed towards the smallest speakers.

I have give the customer the Spanish Inquisition. This is the second time I have looked at this amp. The first time I touched up a few cold solder joints.

I will see if I can put a dummy load on it and inject a square wave.

[Chuck H]

I still think it could be advantageous to request that the customer bring in the entire signal chain that is being used with the 100T. Same as they would for a gig.

[nosaj]

A friend gave me a Powerwerks 100T PA / speaker combo. He said it cuts out on him when he does his singer/songwriter coffee house gigs. Well I have tried everything to get it to fail.

I've pumped lound music through it.
I have left it on for a long time.
I have played guitar through it.
I have used it for vocals.

I can't get the darn thing to fail on me! What should I do?

Go with him to the venue? You might see what he's not unintentionally telling you.
nosaj

[Mick Bailey]

I stopped repairing PA setups because of the problems in getting some to fail - I was stacked out with guitar amps/guitars/pedals which were a quick turnaround, only to be stuck on replicating fugitive PA faults. I have a configurable dummy load which can be configured to stereo or dual operation. I found this to be essential in running high-power setups hard enough to attempt to replicate in-use conditions - you need to soak up the power from the HF as well as LF amps and monitor heat buildup, signal and voltage conditions. The final straw for me was a 2200W per channel setup where one side began to crackle after 2 hours of live use, but only rarely. I'd eliminated cables, speaker mechanicals etc and ran the thing into my dummy load all morning and it was rock solid.

I have a vibrating engraver that's fitted with a rubber stopper on the end of a piece of plastic rod. A super-chopsticker. This will vibrate a board to destruction if turned up to maximum, but this didn't reveal anything. As a last resort the owner came over and asked if we could set it up and run it with music until it failed. He stood right in front of it - no ear protection. I had ear plugs as well as 3M Peltor ear defenders and even in the next room it was deafening. I mean, actually deafening. My hearing and tinnitus have been severely and permanently affected by that session. We never did get it to fail, even with the limiters turned off and tried running it into distortion, playing pre-recoded rock and blues using his cables. You can't replicate floor movement or vibration of a live band, plus recorded music is compressed - you can't get those massive peaks. The very next show it failed - just once - then went back to running fine for another few weeks. I'd had enough.