Film-Tech Forum ARCHIVE: Osram Bulb Analysis=High Inrush/High Current Ripple -Poor Power Supply Question

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Posted by Stephen Frazza (Member # 2320) on 03-10-2005, 12:50 AM:

My boss sent a bulb back to Osram to try and get credit and we got this analysis report back from them.

It was a XBO 1600 W/HS OFR with about 300 hours on it.It wouldnt ignite anymore.Their comment was;

Lamp inspection indicates cathode fissured cause by high inrush and high current ripple from poor power supply.Please check and repair equipment.

It was in a Strong X-90 with a Strong Xenon power supply type 62-80000

After that bulb went we put a new bulb adapter on the cathode side in because the old one looked shot.
Then we had trouble with another bulb that wouldn't ignite but ended up working fine in another projector(same setup)
Our tech said the blower wasn't blowing strong enuff and to replace it, which we are in the process of doing.

My questions are:
How do I test for any problems- I'm trying to get hold of an ammeter but will this be enough?
Also does this type of problem mean the whole power supply is shot or can something like this be repaired?
What's the best course of action here because we don't want to
be blowing threw bulbs like this.

Posted by Monte L Fullmer (Member # 2797) on 03-10-2005, 12:58 AM:

First thing to prevent problems with your rectifier, is to take off the big black front cover, grab a compressor with an "air jack" nozzle on front and blow that rectifier out, since the inner fans are actually pulling in dust and the dust collects everywhere inside, creating excessive heat.

High ripple could be caused by the switching transistors are beginning to fail - due to this heat buildup. I bet that your rectifier is getting ready to fail, which consitiutes a replacement rectifier from Strong.

How old is that X-90 console anywho? on the "X-90" faceplace, there is a manufacturer date when the console was built.

Then when this is all taken care of, dump the Osrams and switch over to Christies - better warranty replacment is the reason. Osram gets grumpy on warranty stuff.

Good luck-Monte

Posted by Jim Ziegler (Member # 86) on 03-10-2005, 02:35 AM:

I have had some early failure of Osrams on X-90s too.. I will try what you have suggested Monte. We have already started ordering Christie's in place of the Osrams.

Posted by Michael Schaffer (Member # 1204) on 03-10-2005, 02:49 AM:

A current clamp like the Fluke i410 is a good and affordable add-on tool for your multimeter. You simply plug it in and the ampère readings are given out in millivolts. A lot of of cheaper amp meters actually only read AC current, so check the specifications carefully before you get one.
However, it has been pointed out that a problem with switching power supplies like the one you have is that it may have high ripple in higher frequencies most amp meters are not sensitive for. Maybe somebody could provide more details about this?

Posted by Stephen Furley (Member # 1277) on 03-10-2005, 07:18 AM:

Osram lamps seem to be by far the most common here.

quote: Monte L Fullmer
Then when this is all taken care of, dump the Osrams and switch over to Christies - better warranty replacment is the reason. Osram gets grumpy on warranty stuff.

You expect them to replace lamps which have failed prematurely due to faults with your rectifiers?

Posted by Steve Guttag (Member # 268) on 03-10-2005, 08:37 AM:

Stephen,

Long ago Osram was blaiming everyone but themselves for their poor lamp lifes....When I was with K-B Theatres in the '80s we got the "your rectifier has high in-rush current" and crap.

The solution...switched to Christie lamps and magically, our in-rush problems also vanished.

It isn't the rectifier persay, it is the bad Osram lamps...this does not preclude rectifier failure and actual in-rush problems nor aged and failing capacitors. However...if trying another brand lamp cures the problem...then that points the finger at the lamp.

Steve

Posted by Gordon McLeod (Member # 33) on 03-10-2005, 09:24 AM:

Well to be fare to Osram they did invent the xenon lamp and wrote the specs on them
Other bulb makers have often different specs on specific items one that always caught my attention was that ushio (christie) had a much higher spec for allowable inrush current probably because of the design of the sanrex rectifiers that ushio had worked on the design of

Posted by Brad Allen (Member # 470) on 03-10-2005, 01:23 PM:

I have 3 Kneisley Kni-Tron Xenex L2000 lamp house's.
I've had problems at times with the igniting of lamps when they are hot.
Could the Osram Lamps be the reason?
I've replaced caps, even replaced one rectifier, and the problem continues.
My dealer swears by Osram.

Posted by Darryl Spicer (Member # 711) on 03-10-2005, 01:37 PM:

We had problems with that years ago on the Xenex 1 Lamphouses I used to work with. Only thing that solved the problem was replacing the existing igniter with strong igniter. No more problems striking bulb when hot.

Posted by Monte L Fullmer (Member # 2797) on 03-10-2005, 02:15 PM:

Now, I'm actually still learning as I go, but I've heard that even though Osram did invent the xenon bulb, and in their early years, had their "teething pains" so to say, (I remember that their used to be a warning in the bulb box mentioning of bulb explosions within the first half-hour of the bulb's operation) yet Osrams were the bulbs to be had-nothing else - no Hanovias, no ORC's, Marbles, et.al. - just nothing can beat an Osram.

Yet, I've heard that ever since Osram and Sylvania joined, that quality has really taken a downward spin with Osrams. Thus these problems started to show up.

Like for an example in a service call that I had last year: a small "indie" theatre that has CH20 consoles. Operator puts in a new Osram "HTP" bulb. Three days later no light. Dead. Ignitor was "sounding" weak. I put in a new ignitor. Better ignition, but still no ignition. Pulled out the diode bank. All six diodes checked out okey. (I was condemning everything in tha console..) -then on to the bulb. Took out the Osram and put in a Christie. "POW" damned thing lit right up. "Freaking Osram bulbs" I hollered.

..one of my many stories with the experiences with Osrams...

..with this, Osrams have degraded themselves to the level of the Perkin-Elmers, which used to be that damned ORC company, IMO.
Told the owner to send this frikken Osram back where it came from and exchange this POS for a Christie at the supplier. Unfortunately, the owner had a bit of a tough time with the warranty due to the small amount of hours on that Osram. But I heard that the owner won this one.

This "indie" house is now using Christies and have no problems ever since.

thx-Monte

Posted by Richard Fowler (Member # 893) on 03-10-2005, 02:44 PM:

Years ago Osram had the advantage of using a process to treat the electrodes with a radioactive doping procedure to help on life extension....this is no longer allowed.

Posted by John Pytlak (Member # 331) on 03-10-2005, 02:58 PM:

quote: Richard Fowler
Years ago Osram had the advantage of using a process to treat the electrodes with a radioactive doping procedure to help on life extension....this is no longer allowed.

So do modern xenon lamps of any make still contain radioactive electron-emission enhancers like Thorium?

http://www.toshiba-tmat.co.jp/tmat/eng/material/e_tan_7.htm

quote:
4. Discharge lamp parts
We manufacture pure tungsten parts and special elements alloyed tungsten parts for xenon lamp electrodes or other gas discharge lamps.
For the cathodes requiring electron emission, we offer thorium tungsten W56.

Posted by Richard May (Member # 2627) on 03-10-2005, 05:42 PM:

For what it's worth, most of the theaters around here use Osrams and never had a problem. I have rarely heard of an Osram bulb coming up short on hours. On the other hand, I have seen many problems with Christie bulbs. Go figure. [Confused]

Posted by Monte L Fullmer (Member # 2797) on 03-11-2005, 04:28 AM:

quote: Richard May
For what it's worth, most of the theaters around here use Osrams and never had a problem. I have rarely heard of an Osram bulb coming up short on hours. On the other hand, I have seen many problems with Christie bulbs.

..can't argue with this one. Seen 2k Osrams pull over 6k hours (envelope blacker than pitch with anode plugs with nasty tungsten buildup), to where they puke out right after warranty hours for no reason or another.

Seen Christies run as long, only with clear envelopes and the still knarly looking anode plugs, to where they also puke out well under warranty.

..It's all up to the indivdual user on what they prefer...

Yep, it's a go-figure thing.

-Monte

Posted by Bob Brown (Member # 1205) on 03-12-2005, 03:01 PM:

I have a question here... I know a projectionist that has a pair of OSRAM XBO 7K lamps that were "reburned" from OSRAM. I think they were sent under warrenty back to OSRAM for flickering, they both have about 200 hrs on them. What exactly is meant by the term "reburned"? What is the "reburning" process

Thanks

Posted by Monte L Fullmer (Member # 2797) on 03-13-2005, 03:49 AM:

quote: Bob Brown
What exactly is meant by the term "reburned"? What is the "reburning" process

..much as I can gather is that the bulb is arced under very high amperage-higher than the bulb's amp settings, to "season" the cathode/anode plugs inside the envelope. This procedure is done with an "Off/On" sequence many times within a time frame.

..but don't quote me, for this is just what I've heard.

-Monte

Posted by Mark Gulbrandsen (Member # 72) on 03-13-2005, 04:48 PM:

There are people getting good life from Osrams but wait till they send that one troublesome lamp in for warranty... they will be awakened when they read Hi Inrush and ripple on their lamp repirt and finally realize why most people that use them eventually switch over to Chriistie.

Monte,
with switchers which operate in the mid 30 khz region high inrush current is not caused by transistor failure. The output of the switcher goes into a small high frequency/high current transformer of which the secondary is rectified and that DC is sent to the lamp. Hence bad or intermittent transistirs cannot cause high inrush current. Your main problem is the X-90 and its poor ventallation system. The only way to handle it is with about 800 to 900 cfm of air movement per console!!

Mark

Posted by Richard May (Member # 2627) on 03-13-2005, 09:49 PM:

If I get one troublesome lamp from Osram out of all the theaters that I service that use them, compared to the number of Christie bulb problems that I have dealt with, I'll take that anytime. [thumbsup]

I don't understand why Osrams work for some and Christies work for some. It makes no sense. But from what I have been hearing here, it seems that it is the case [Confused]

Posted by Monte L Fullmer (Member # 2797) on 03-13-2005, 10:07 PM:

quote:
The only way to handle it is with about 800 to 900 cfm of air movement per console!!

Then, what's funny then is why doesn't STRONG recommend such a exhaust requirement of such magnitude then if such problems like these point towards the exhaust remedy?

Granted, that "muffin" fan concept that blows on the anode connection of the bulb is about as goofy of a design that I've ever seen. Prob why I can't get great hours when running a 2500k bulb in an X-90 console - not enough airflow going across the anode seal. They should take the blower hose concept of the SLC-45 consoles of Christie to cool down the anode connections. Then they would have something!

...another one of those "go-figure" things from Strong, I guess.
(thx Marko, on this..)

-Monte

Posted by Mark Gulbrandsen (Member # 72) on 03-13-2005, 10:28 PM:

quote: Monte L Fullmer
Then, what's funny then is why doesn't STRONG recommend such a exhaust requirement of such magnitude then if such problems like these point towards the exhaust remedy?

Thats something that ALOT of people have been trying to figure out for years!! It just may be that they also sell parts and Xenon lamps too...... or that they just don't quite have it together.... a bit of both I would presume.....

Mark

Posted by Stephen Frazza (Member # 2320) on 03-14-2005, 02:56 AM:

We had trouble again with a almost new bulb in this lamphouse, not wanting to ignite at all.But we had a spare rectifier so I changed it out and all seems to be ok now.

quote: Monte L Fullmer
How old is that X-90 console anywho? on the "X-90" faceplace, there is a manufacturer date when the console was built.

Monte the face plate says 3/91

Some more questions;
the bulb adaptor on the cathode side and the 2 cables to the anode and cathode side of the bulb, do these go bad.
I mean does the resistance in them goes up and it gets harder to push current threw them.
Is there any way to check this?
Or if not when and how often should you switch to new ones?

Posted by Monte L Fullmer (Member # 2797) on 03-14-2005, 03:08 AM:

quote: Stephen Frazza
the bulb adaptor on the cathode side and the 2 cables to the anode and cathode side of the bulb, do these go bad.
I mean does the resistance in them goes up and it gets harder to push current threw them.
Is there any way to check this?
Or if not when and how often should you switch to new ones?

The big secret is to have any connection TIGHT! Electricity, especially DC, loves to find weak spots and heat up things to oblivion.

The anode cables are sealed on the anode ends and thus never any problems with these. It's just the "O" ring blade connection cable to the positive shunt with that brass screw must be TIGHT!

Same thing with the cathode adapter end being brass: must have TIGHT connections to the cathode end of the bulb. Anytime it get's loose, it will actually melt the brass down due to the immense heat from the resistance buildup.

I've only seen spattering of heated cables where the age of the bulb can take so much and the metal seals on the ends of the bulbs get tired and will break down with massive resistance, thus get real dark. If the bulbs gets this way, time for a change, or a defective manufactured bulb.

KEEP your connections TIGHT, Tight, Tight. And you won't have any problems.

-Monte