This is topic Fireworks in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Jon Bartow (Member # 241) on 10-11-2001, 12:00 PM:
Check this out... 
This amp had sparks visible from several feet away and had blown a lot of ashes out the exhaust fan in the back all over the floor.
Just for reference this is an Ashley FTX-2001.
Jonathan
Posted by Gordon McLeod (Member # 33) on 10-11-2001, 10:35 PM:
That is why they are call ASH-leys 
Posted by Adam Martin (Member # 641) on 10-11-2001, 11:31 PM:
Today we powered up a rectifier to find that a bad transformer shorted two legs to ground. It blew breakers two panels upstream and sent sparks all around the room. Oh, and gave a bunch of electricians heart attacks!
Posted by Dick Vaughan (Member # 540) on 10-12-2001, 01:56 AM:
AdamWas this one of the Millers for the IMAX system? Any clues as to why this happened?
Posted by Adam Martin (Member # 641) on 10-12-2001, 09:48 PM:
Yep... for the Imax SR. The electrical contractor mis-labeled two of the wires between the panel and the fusebox for the rectifier. It sent a phase through one chassis, through the conduit between the two rectifiers and blew when it hit the other chassis which was properly grounded. Good thing nobody was touching anything. Turns out that the bad transformer was just a result and not the cause.And we're still not on screen yet. Hopefully tomorrow morning.
Oh, and I guess it would help to explain that this is a new build.
Posted by Paul G. Thompson (Member # 655) on 10-15-2001, 11:33 PM:
Jon, was that where a bridge rectifier was mounted? I wonder what size fuse was protecting the unit.
Posted by Jon Bartow (Member # 241) on 10-16-2001, 09:53 AM:
Paul,
I don't remember what is on the other side of the circuit card in that corner. It's been a while since I have actually repaired an Ashly. This particular amp though: None of the three fuses (main 120v input, and one each on each of the internal modules) had blown, and the other side was still operating even as sparks were creating quite a show on the side pictured. Not pictured is the edge of the circuit board next to the heat sink where all of the transistors are (10 of them?) Every single one burnt up and burnt the circuit board. If you look carefully at the picture above you can see that whatever component was on the other side actually burnt three holes through the circuit board.
Also: this amp was running at about 1/2 rated power pushing a 6ohm load through JBL 8330's
Jonathan
Posted by Jon Bartow (Member # 241) on 10-22-2001, 08:26 PM:
Had another Fireworks incident with an Ashly today:
An Ashly FET500M died in the form of DC output.
On the Screen end was (and I emphasise WAS) a JBL 4446 (I think that's the model number) with the two 2225H speakers in it (15").
The lower driver cought on Fire. Yes Literally burning. It totaly destroyed the lower driver (as in turned the cone into a pile of ashes on the floor), blistered a fair amount of the paint on the cabinet, blackened the fiberglass insulation in the cabinet and apparently caused quite a stench in the auditorium a few days ago when it actually happened. It also turned that rubber mounting gasket into a ring of glue. It was all I could do to pry that speaker out of the cabinet.
Oh and the upper driver was fully distended as well as being a bit crisp along the lower edge.
All in all a fun morning behind a mid's eighty's psuedo-baffle wall, complete with mid-eighty's through 2001 dust.
Sorry no pictures
Jonathan
Posted by Don Sneed (Member # 955) on 10-22-2001, 09:19 PM:
I was it a 8-screen theatre in Houston (for you william the "Windchimes theater") that we just taken over the service contract a month earlier, the theater had Raven Ace-100 Amps....the worst amplifier ever made....I was just handed the keys to the speaker room, went to tune the sound system when I had no sound from the center channel using pink noise...since the monitor did not work I had the port window open...I went to see what the problem was with the speaker & saw a glow coming through the screen, opening the speaker room door & smell & saw smoke...turning the Altec A-7 around, the woofer was glowing like a big cigarette.....whoooaaa weeee I had to use a fire exting. (sorry laptop can't spell) to put it out....what a mess that was...this happen twice on another screen....needless to say those amps was quickly replace with QSC..that was the only time in my 25 years of service I ever seen a speaker on fire !!
Posted by Gordon McLeod (Member # 33) on 10-23-2001, 09:10 AM:
Funny I have had very few problems with Raven amps. Over the years I have used many of there mobo systems and quiet a few multitrack ones with no problems to speak of.