What went bang, smelled of "I'm fried", yet left it in working order...???


Hi gang - wasn't sure if this should go here under amps or tech talk, but here goes: normally, I'd call the salesman I work with at my LAD, but they're closed Sun. & Mon. and I'm loosing sleep over this as I feel I'm on very thin ice.

My wife and I were watching a movie late last night, and after the movie we were sitting on the coach discussing it when we both jumped when we heard a loud bang coming from the media console and smelled an electrical burn. Sitting on top of the console is a Dan D'Agostino Progression Stereo power amp, a McIntosh C53 preamp, and mounted directly behind this on the wall, a Panasonic plasma TV.

Nothing tripped a fuse, the TV was still on, both sets of power meters on both the Dan & Mac were still lit. I streamed a test track that has a lot of bass that when I turn up to a certain volume, has the Dan's power meters hang at 400 watts for a few seconds, and they did - just like always. Everything seems to look and sound fine.

So, while I'm not asking for anyone to try and guess which of those three components made the bang, what I am asking is for any of you here who have an electronics background tell me what electronic part (in either the preamp, amp or TV) possibly could have made a loud bang releasing an electrical burn smell, yet "seemingly" leave everything still functioning as normal...?

--thanks and cheers!

128x128jimmy_jet

There may be very little left of what ever blew up. Open the cover and look for two short wires sticking up from the circuit board or wherever the parts are concentrated. Electroltics and varistors are relatively cheap. Also look for where the power line comes in. Don't run it without getting it repaired. Something really expensive might go as a result of whatever popped. Good Luck.  

Capacitor, smell first and open the offending component cover and you should be able to find the culprit 

you have the likely culprits. MOV, capacitor, possibly the safety cap.

 

So the next question is "why?", "what did it do?" and ho to replace. Obviously the repair is influenced by why a cap failed. There are cues for anyone who knows the design int he fact that its still working. Sometimes products are in parallel and one can go. Sometimes they are intended to filter out noise in certain places, and maybe a 2nd order impact on performance/sound. But they are all there for a reason.

 

Let’s establish one fact: electrolytics capacitors are not the world’s most reliable parts. They die early. They die without obvious reason. The one predictable failure mode is old age, but your products are far too new. I am offering recap on some series of stuff i designed 30 years ago - and the vast majority are still in service. 5 or 10 years old is nothing. By way of contrast, I just got shipment of high quality 100v parts all of which fail at around 20V. QED.

 

I’d really hve someone who knows the design at minimum diagnose the reason.

 

One more possibility: an insect. Insects can become conductors if the voltage is high enough they might go bang themselves or possible conduct change voltage levels or loads and make a capacitors go bang. Seen that!

 

G