Film-Tech Forum ARCHIVE: Strong X90 / Compact Switcher Fire!

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Posted by Pete Naples (Member # 761) on 12-01-2004, 11:32 AM:

Well nearly a fire, the CNA200 shut the show down when the lamp went out, after the AC input connector decided it preferred a gaseous state of existence!

The operator was alerted by the CNA200 alarm, smelt burning as soon as he walked in the booth door, apparently he could see the connector glowing when he opened the console rear door, and decided now would be a good time to kill the power!

Posted by Mark Gulbrandsen (Member # 72) on 12-01-2004, 12:35 PM:

I've seen this before. This is why it pays to go through and tighten up all your conenctions every couple of years. The DC connections can do the same trick.

Mark @ CLACO

Posted by Brad Miller (Member # 2) on 12-01-2004, 01:49 PM:

I wish I was carrying around a camera back when a few of the Strong Highlight rectifiers around town were catching fire. Gotta love getting one of those phone calls "hey, when you can see flames coming out of the edges of the Strong lamphouses, that's a bad thing right?"

Posted by Monte L Fullmer (Member # 2797) on 12-01-2004, 03:35 PM:

Yep, also seen that one before..up on Ontario with that plug going into that "switcher". Remember Mark when you called me to go do that fix when I was still with EDW's, a couple of years ago? I keep on checking these plugs at least every other month now up there. - thx Monte

Posted by Pete Naples (Member # 761) on 12-01-2004, 04:37 PM:

Thing is Mark, these DO get checked regularly, in fact I checked what was left of the pin and screw terminal, couldn't get it any tighter! I can only asume that the surface of either the wire or the terminal had oxidised slightly.

I too have seen the DC connection do this, although not on the Amphenol connector type, on the ealier type with hard wired connections.

Posted by Mark Gulbrandsen (Member # 72) on 12-01-2004, 07:25 PM:

Pete,
The thing that switchers do not like is excess AC voltage weather it be over the long term or as surges or spikes. Since we started installing the whole panel surge protection devices we have not seen a switcher failure. Before that it was one or two every 6 months... and there are ALOT of switchers in this area. Did this location have surge protection?

BTWL We have seen this same thing happen with QSC power amps in one local plex. Ots pretty impressive to have the fan turn the amp into a flame thrower that is large enough to roast Hot Dogs with. Turns this location had quite high line voltage overall, they also hold the worlds record for the number of switcher repairs..
Mark @ CLACO

Posted by Randy Stankey (Member # 64) on 12-01-2004, 08:50 PM:

quote: Mark Gulbrandsen

We have seen this same thing happen with QSC power amps in one local plex.

Isn't that because there was a run of defective units?

I was told that there was a printed circuit card that was made just a milimeter too wide for the edge connector that it was supposed to mate into. Instead of rejecting them and making new ones, they squeezed the F-ed up ones into the slots. The board bowed slightly but it worked... for a while... until the power connections corroded and overheated.

Posted by Mark Gulbrandsen (Member # 72) on 12-01-2004, 09:05 PM:

I hadn't heard that one but anything is possible. They did have excessively high line voltage though. The amp that "flamed out" was about 5 years old.

Mark

Posted by Randy Stankey (Member # 64) on 12-01-2004, 11:44 PM:

We have all QSC amps here at the PAC. I have been through many rounds of, "Oh! You have QSC amps!... The ones that spontaneously catch fire!"

Though ours are going on 10 years old, we have only ever had to replace ONE of them. At no time did one ever go up in flames. I finally asked around and got that story.

Appearently it happend when the company moved its production facilities from one city to another. All the amps that were made pre-move are good. The ones that were made just post-move are the bad ones. After a while they redesigned their products and the problem went away.

Our amps are of the pre-move variety. We don't expect to have any problems from them in a long time.