Film-Tech Forum ARCHIVE: Xenon Power Supply Help

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Posted by Nic Margherio (Member # 273) on 12-03-2001, 06:57 PM:

I had an ORC XPS-20 power supply go bad over the weekend in an ORC DV-2000 lamphouse. Instead of trying to repair the supply, (I'm not exactly sure what is wrong with it) I have rigged a 1-3K Strong switching power supply into place temporarily.

My problem is this: I cannot figure out how to get the switcher to acuate the high-voltage ignitor. Presently, I am required to use the "Manual Start" switch on the lamphouse (witch supplies the "no load" voltage to the ignitor via a seperate 115 feed) in order to strike the bulb. Once ignited, the switcher takes over and supplies current to the bulb quite nicely.

Is there any way to get the switcher to generate "no load" to the ignitor? If I understand correctly, a switcher generates DC "no load" and must be used in conjunction with a DC ignitor. If this is true, how do I utilize the manual igition circuit to strike the bulb automatically? Thanks for any input.

Posted by Pat Moore (Member # 380) on 12-03-2001, 08:41 PM:

Nic;

That Switcher should supply lots of open circuit voltage, at least 120VDC or more. Might be something in the lamphouse's auto-strike circuit that's not right. Did that series of ORC lamps have an adjustable strike point, or was it fixed? Sorry, don't remember...

You should be able to put a volt meter across the DC output and see what the open circuit voltage is. Careful, though -- if the auto-strike decides to work it might zing your meter but good.

The Switcher will work with standard AC Igniters without a problem -- it just has a naturally high open circuit voltage characteristic.

Pat

Posted by Gordon McLeod (Member # 33) on 12-03-2001, 10:29 PM:

Some of the ORC lamphouses had a test point on the back for measureing voltage
The autostrike in the ORC is usually just a R10 relay with a zenier diode connected to it from the D.C mains

Posted by Nic Margherio (Member # 273) on 12-03-2001, 11:45 PM:

Pat,

I'm not certain that I am making the right connections between the igition switch and the swithcher. Currently I am using terminals 6 and 7 on the switcher (it is a 1994 vintage hard-wire) to close the internal contactor in the switcher. None of the other terminals are being used. Will the switcher acuate the igniter (generate adequate VDC) just by closing the contactor?

The igniter does have an adjustable strike gap. I am a little leery of putting my meter across the DC leads for reasons that you have already stated. Unfortuantely the installed volt meter on the lamphouse has not worked for some time. I'm thinking I will switch that meter out with a known good one to see if any no-load voltage is being supplied.

Thanks for your help.

By the way, Gordon, what is a zener diode anyway?

Posted by Steve Guttag (Member # 268) on 12-04-2001, 06:29 AM:

6 & 7? wow are you lucky!

Strong sends voltage up to the lamphouse on 2 & 4 (120VAC) and expects it back on 5 & 6 to close the contactor.

Terminals 7 & 8 are strictly 208VAC and are there to drive an upper blower on such lamphouses as the Ultra-80

Terminal 3 is for automation switch legs...goes out to the auto on 3 and comes back on 6.

Steve

------------------
"Old projectionists never die, they just changeover!"

Posted by Paul G. Thompson (Member # 655) on 12-04-2001, 12:23 PM:

In addition what Pat said and Gordon suggested, be very careful about inadvertantly leaving an electronic digital voltmeter connected to the test points in the back of the lamphouse. Should ignition occur, you might ruin the voltmeter, especially if the RF suppression capacitors are not up to par.

This happened to me once, and it did so much damage to the voltmeter that it was rendered beyond repair. The manufacturer of the digital voltmeter sent me a letter asking me what I did to it. I told them, and they sent me a replacement meter free with a letter saying, "please don't do it again!"

Posted by John Pytlak (Member # 331) on 12-04-2001, 12:45 PM:

Paul said: "This happened to me once, and it did so much damage to the voltmeter that it was rendered beyond repair. The manufacturer of the digital voltmeter sent me a letter asking me what I did to it. I told them, and they sent me a replacement meter free with a letter saying, "please don't do it again!"

Kudos to that voltmeter manufacturer. Voltmeters done right!

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Pat Moore (Member # 380) on 12-05-2001, 09:59 AM:

Nic;

I don't think that Switcher has a terminal #7 -- as Steve says, 115VAC to terninals 5 & 6 will turn on the contactor and the supply, regardless of where the AC comes from. You'll get all the open circuit DC voltage then as well.

If the lamphouse is not trying to auto-strike, then you should be able to read the open circuit voltage and not worry about your meter. Just don't leave it hooked up longer than necessary.

I'm an electronics dummy, but... a zener diode blocks voltage up to a certain level and then passes anything over that threshhold. A 50V zener will block 50V. If you've got 60V hooked up to it, it blocks 50V and you should only get around 10V out of the circuit. The zener diode in the auto-strike circuit is generally used to control at what point a relay is activated to turn the igniter "on". The ORC Lamphouse should have some circuit like that to provide AC Power to the igniter. Take a look at the rela's contacts, see if they are badly pitted. You might look at the socket and relay pins for corrosion. If things are wroking right, you should actually see the relay pull in at some level of open circuit voltage -- like I say, the Switcher will provide plenty. If the relay doesn't pull in, suspect the relay or the little zener diode in that circuit being open.

Pat

Posted by Gordon McLeod (Member # 33) on 12-05-2001, 12:06 PM:

In most of the older ORC the relay and zenier were mounted on the front of the reflector bulkhead on the non operating side and the ignitor itself sat on the base of the lamphouse below it

Posted by Pat Moore (Member # 380) on 12-05-2001, 01:30 PM:

Another thought -- didn't most of these ORC Lamphouses have a pot that controlled the firing voltage? Nic, you might take a look for a small potentiometer in that igniter circuit. The pot further controlled the voltage in addition to the zener diode in the circuit. It might be that the pot is adjusted for too much resistance or that it's open, and that would keep the igniter from firing automatically. The manual ignite button bypasses all of this auto-strike circuitry.

Pat

Posted by System Notices (Member # 2357) on 12-04-2004, 12:31 AM:

It has been 1094 days since the last post.

Posted by Justin West (Member # 920) on 12-04-2004, 12:31 AM:

I, too, have a problem with a Strong Switching Power Supply:

In fact, I have two Strong Switching power supplies. When I bought them, I was under the impression that the unit marked "A" below would be usable with single-phase service. Unit "B" is a three-phase, 4-7 kW model. Both models are obsolete.

A) Model 6284001, Ser. 19467 Mfd. 8/98
Input: VAC 100-130, Amps 30
Output: VDC 18-28, Amps 25-70

B) Model 6284001, ser. # 4915, mfd. 12/93
Input VAC 208/240, Amps 40 Max.
Output VDC 30-50 Amps 100-170

I opened up unit "A's" cover panels to do some light vacuuming and check on connections, etc. and I found a note that was placed in there from a previous owner. It said, "Burned Resistor(s) main board at power input circuit." I looked around and I found some light soot covered resistors and a diode near the DC output cables. None of the resistors or the diode in question looked burned, popped, or broken, and the soot was wiping up fairly easily with a rub of my finger. [The resistors and diode in this area are R98, R99, R117, R118, and D44.] Maybe it was fixed...I don't know that yet. I tried running 120VAC to the power supply input terminals and jumpered the "lamphouse control circuit terminals" #3 and #6, then flipped the circuit breaker switch to see if any DC current would come out the output terminals and...nothing. I have no lamphouse connected (and none to connect to this at this time) so does anyone have any advice on what I should jumper to get a reading? Maybe 2, 4 and 5, 6?

I also have 2nd part to this question: I spoke with the Tech Service Rep at Strong and he was very supportive and concerned but he was stymied by the fact that the model or "type" numbers were the same and that they and their serial numbers matched up as both being 3-phase, models to power 4-7kW xenon bulbs...but the input VAC and output DC Amps were definitely lower on the data plate from Unit "A." The way I read Unit "A's" info, it makes it sound like it takes your standard 120 volts and puts out maybe 2kW? Am I offbase here? Why the discrepancy? Has anyone else experienced this? Strong will no longer service either of these units. Thanks for any advice.

Posted by Aaron Sisemore (Member # 145) on 12-04-2004, 01:56 AM:

Strong won't service a switcher made in 1998?!?!? I have had switchers made in 1993 and 1997 repaired by them with no problems.

-Aaron

Posted by Justin West (Member # 920) on 12-04-2004, 08:38 AM:

Strong issued a repair policy update in August, 2003 (see downloads-product bulletins on www.strong-cinema.com ) to announce that certain parts would no longer be available for these units that were "Version 0" models...they would keep repairing for as long as the parts held out. I guess they've run out of parts... [Frown]

Posted by Mark Gulbrandsen (Member # 72) on 12-04-2004, 01:12 PM:

We recently had a 7kw switcher repaired that had been given to us. Wasn't cheap to have done, I think our cost was about 700 bucks. The resona the older switchers cannot be repaired is due to semiconductor obsolescence. A very common problem in computer and semi based equipment. This is one of the main readsns that DTS can no longer support the DTS 6. Even the APTX decoder chips are NLA.
That Strong bulliten is outright hilarious! They say "Upgrade to a high reactance supply" in there as an option.... That my frineds is a very serious downgrade [thumbsdown]

.

Mark

Posted by Justin West (Member # 920) on 12-05-2004, 11:04 AM:

I have since tried to emulate a completed lamphouse circuit by jumping terminals 2 to 5 and 4 to 6...then connected 120vac to the L1 and L3 power-input terminals and flipped the switch, then attempted to measure VDC output on the DC output connectors...nothing! [Frown]

Maybe I will need to try the same thing only find someone with 3-phase service...or else something really was zapped on the circuit board in this unit.

Posted by System Notices (Member # 2357) on 04-17-2008, 10:58 AM:

It has been 1228 days since the last post.

Posted by Ken Lackner (Member # 1002) on 04-17-2008, 10:58 AM:

Does anyone know of a shop that repairs the "Version 0" supplies? I have a couple that are dead and I'd really hate to just junk 'em. I imagine the cost of repair, if anyone can do it, would be much cheaper than buying a new one the next time one dies.

Mark, why do you say that a high reactance supply is a downgrade? They are far more reliable.

Posted by Mark Gulbrandsen (Member # 72) on 04-17-2008, 07:58 PM:

Ken,

Switchers are no less reliable than a high reactance supply if properly installed. Strong's high reactance supplies have a horrible reputation for many, many reasons and in fact if you have ordered a high reactance supply from Strong in the last say 4 or 5 years you will get one manufactured for them by LP Associates. The LP's are much better than the Strongs were. Lamp life with a switcher can be very long as the 35khz or higher switching frequency is basically invisible to the bulb itself. Inrush current can actually be finely controlled instead of just a theoretical value they is never quite met. The switchers from Strong are not the only ones around... They are also made by IREM and Sanrex. They are also quite easy for any qualified tech to repair. Contrary to popular beliefs it is not necessary to send a switcher back to Strong to get it repaired.

Mark

Posted by Sean McKinnon (Member # 612) on 04-18-2008, 12:49 PM:

In my (limited) experience I have found the brute force high reactance type supplies from strong to be a lot more reliable than the switchers. I know of many complexes that had to change out all 20 switchers for the ORC style high reactance supplies.

Posted by Mark Gulbrandsen (Member # 72) on 04-19-2008, 02:11 PM:

quote: Sean McKinnon
I know of many complexes that had to change out all 20 switchers for the ORC style high reactance supplies.

Sean... They should have repaired the electrical problem at hand first! They will also more than likely suffer from more than normal number of diode failures down the road a short ways as well as lots of premature light bulb failures. I've seen this very same thing happen... Megaplex Theaters here in SLC had massive switcher failures in their first build. They also had QSC power amps shoot flames out their fronts... something they more or less never do. The culprit there was high line voltage... almost 130 volts steady state... I can't imagine how high the spikes were... In the second build whose line voltage was a bit more normal they installed high reactance rectifiers and still suffered an occasional diode failure. Ditto at location three. No surge supressors were installed on the booth panels at all!!

Mark

Posted by Sean McKinnon (Member # 612) on 04-20-2008, 10:07 AM:

Well, this particular theatre is in Danvers, Mass which is NOTORIOUS for dirty power, especially the area where the theatre is around the mall. They had a six screen across the highway that suffered brownouts constantly during the summer that would trip off all the sound processors and automations. They also went through Diodes (Christie CH series consoles) like crazy. When they built the 20 across the highway at the mall they put in all Strong Highlight II consoles with switchers. They had major problems with them burning up and not building up enough open circuit voltage to strike the lamp. After having Mass electric and Strong reps out at the theatre they finally replaced them with the ORC style high reactance supplies. Suprisingly all the issues went away. Lamps would light on the first try, and for some reason they rarely lose diodes anymore? The six across the highway re-opened as an independant seven screen with Christie CH, and SLC consoles and they still AFAIK go through diodes often. I don't know if the power company changed anything around the same time that they replaces all 20 switchers bug it was pretty amazing how all the issues went away after the swap.

I also worked at a theatre that had Super-Lume X lamp houses on switchers. One of the switchers was replced with the vintage of power supple where strong changed the washers on the DC output to I think one brass and one steel maybe? Well, the problem with that is different metals will expand and contact differently when they get hot so after a while of the washers expanding and contracting at different rates it managed to work the connection loose causing more heat etc... One day I was working the concession stand when a customer came out and said that there was no picture on the screen. I opened the booth door and the stairway was filled with smoke. I ran up and killed all the power and when I investigated I found that it was the switcher that had caught on fire, the DC output terminal had burned up! Strong replaced the unit free of charge!

Posted by Mark Gulbrandsen (Member # 72) on 04-20-2008, 10:46 AM:

quote:
I ran up and killed all the power and when I investigated I found that it was the switcher that had caught on fire, the DC output terminal had burned up! Strong replaced the unit free of charge!

YEP! This happens because either the DC lead was not tightened properly or the nut on the back half of the DC terminal was not tightened properly at the factory, I think Wrong has modified that tterminal board as well. This is a good example why through maintainance is a necessity. In all fairness to Wrong International this same problem happens on all other makes and brands of rectifiers too... I;ve seen both Irem and Christie rectifiers high current connection areas go up in smoke. Preventative maintainance catches alot of this stuff but not 100%. I also check inside breaker panels on alot of first time service visits... lots of loose breaker screws to be found.

Mark

Posted by Sean McKinnon (Member # 612) on 04-21-2008, 09:31 AM:

I think what exasperated the problem was Strongs brief switch to two different types of washers on the connection. Different metals will expand and contract at different rates. If you mix brass and steel for example, that is why (as you said, Mark) I ALWAYS check those connection during routine maintenance. I don't want anyone to have to go through what I went through at the tender age of 16 having a switcher belching smoke into the booth like crazy! [Big Grin]

Posted by Dave Macaulay (Member # 813) on 04-21-2008, 10:23 PM:

Strong has used the same rectifier to lamphouse wire numbers since dinosaurs walked the earth. Some have disappeared but the basic five are unchanging.
Wires #2 and #4 are 120VAC power to the lamphouse from the rectifier with about 500VA worth of power available.
Wires #5 and #6 are the rectifier on inputs. On high reactance models these go to the power contactor's coil through some thermal safety switches. On switchers the workings are different but the effect is similar - apply 120VAC and the rectifier starts making DC lamp power.
Wire #3 is a dummy, used to pass an automation's "lamp on" relay contact up to the lamphouse so the AUTO/MANUAL switch can finally have a purpose.
To trick the unit into making DC power without a lamphouse, jumper #2 to #5 and #4 to #6 then turn on the AC feed and the rectifier breaker (if it has one). This usually works, but... there's a trick thrown in by Strong - some console rectifiers have an internal connection between some terminals (I don't recall which - 2 to 5, 2 to 6, 4 to 5, or 4 to 6...?) and you might just get some buzzing and general lack of DC power. Some have a console/lamphouse switch, set it to lamphouse. Others are just wired different with no outside indication, try a single jumper from #2 to #5, if that doesn't work try #2 to #6, then #4 to #5 and then #4 to #6. One should work. The "wrong" connection may be shorting out the 120V lamphouse supply, overloading the little step-down transformer, so don't leave the thing powered for long if it isn't making DC power.
Some switchers have an external mega-size fuseholder with a relatively unobtainable (ie special order in most of the world) special type fuse inside (16A super fast blow) and a really special trick: if you remove the fuse to check it because the danged supply isn't making power... and the fuse tests good... when you put it back in it does blow, instantly - unless you've left the rectifier powered off for a half hour or so. Sweet, eh? Later models have the same fuse and same trick but locate the fuse in a fuseholder hidden underneath one of the many-screwed covers. The fuse rarely blew in operation (and usually meant a fried DC block) but boy a lot of them were destroyed by "testing".