Film-Tech Forum ARCHIVE: Diode problem on Big Sky Lamphaouses

This is topic Diode problem on Big Sky Lamphaouses in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Kelly Skaggs (Member # 1780) on 09-06-2004, 05:39 PM:

We run Big Sky C2000 Console lamp houses, we are going through diodes on one at the average of about 1 per week, it is set up to power a 2K bulb. Is this a common problem with any one else unlucky enough to be running Big Sky? If this has been a problem in the past what did you do to fix it?

Posted by Gordon McLeod (Member # 33) on 09-06-2004, 05:48 PM:

Assuming that the rectifier isn't beeing over driven or overheated due to a failed exhaust problem then I would bet you have a HighVoltage issue getting back to the rectifier from the ignitor
especially at the speed they are failing
I assume it is an Irem rectifier I would look for a bad ground connection in the ignitor/lamphouse section and a bad baypass capacitor

Posted by Mark Gulbrandsen (Member # 72) on 09-06-2004, 05:52 PM:

That should be an IREM rectifier in there. And no you shouldn't be having these problems. Best to replace ALL of them at the same time and be sure to use the same diode that was in there. Stay away from substitutes. If the problem still persists then carefully check any bypass capacitors in both the rectifier and console and your ignitor assembly for proper operation. Also be sure that all DC cables are tight at the connections and that nothing is touching the chassis(ground), perhaps the positive lamp lead(?).

Mark @ CLACO

Posted by Steve Guttag (Member # 268) on 09-06-2004, 08:54 PM:

I dunno Mark...IREM is pretty skimpy on their diodes...we have some N3-180s installed (180-Amp) and IREM only saw fit to supply 70-Amp diodes in the DO-5 package. I generally install 85A 1600PIV diodes when changing any DO-5 packages.

I agree with others on the diagnosis though. If it is just one console that is having issues...I'd look for wiring problems and failed/missing noise suppression caps around the igniter.

If it is the entire complex, then I'd look towwards your building power having a bunch of noise and brown-outs. We have two complexes that chew through diodes (different rectifiers) whilst others (using the same rectifiers) have maybe a diode failure every 5-10 years.

Steve

Posted by Mark Gulbrandsen (Member # 72) on 09-06-2004, 10:25 PM:

I don't know what they use as stock on Irems as there are not many around here but our standard replacement is also the 85A 1600 volt. I thnk just about everyone servicing uses them at this point in time. If only the manufactuers would use them....

Mark

Posted by Dan Reiter (Member # 1386) on 09-10-2004, 08:43 AM:

The IREM supplies are usually extremely reliable. If problems occur, it is usually due to an external problem. Diode failure usually occurs from excessive heat from inadequate ventillation, loose connections or mounting, un-equal or missing input phases, or other problems. Also check for burned contacts or loose wires on the contactor inside the IREM supply. If a failure does occur, replacement of the pair of diodes for that phase is the minimum amount to be changed, with replacement of all diodes the best way.

The IREM power supplies have been around for 50 years, and have been the standard of which other magnetic supplies are measured against. I have personally worked on some supplies 30 years old that have yet to be serviced, and still operate like new.

On our corporate site, www.bigskyindustries.net there is a page on proper troubleshooting for diode failure. Please refer to it to help you with future repairs. If you have any other related questions, I'd be very happy to help you personally, just contact me here at BIG SKY M-F 8:30 to 5:00 EST.

Posted by Mark Gulbrandsen (Member # 72) on 09-10-2004, 06:06 PM:

"The IREM power supplies have been around for 50 years, and have been the standard of which other magnetic supplies are measured against. I have personally worked on some supplies 30 years old that have yet to be serviced, and still operate like new."

I don't think they are quite the standard to judge other by because they have to much ripple. Christies are much cleaner operating supplies overall. Thirty year old capacitors in some old supply is not a good idea in most necks of the woods!

Mark @ CLACO