Film-Tech Forum ARCHIVE: Zenith ZX4000H too Dark

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Posted by Demetris Thoupis (Member # 833) on 06-22-2005, 05:48 AM:

A cinema was upgraded some years ago to the above mentioned lamphouse. Even though the installer did a damn good job in putting the damn thing on a V8 projector (really old) and getting all the distances e.t.c exactly as they are in the manual, the damn picture is too dark even though it is projecting with an USHIO lamp of 4kw at 135A (rated amp). I've cheked the lamphouse and it looks straight in the middle (lamp to gate). Checked it through the lens holder, put a damn laserpointer thingy e.t.c, dummy bulb e.t.c but still the immage is too dark. It looks straight but when the film is running and watching the light through the green glass (where the shutter is) the light seems to be hitting offset left. Any ideas?
D

Posted by Richard Fowler (Member # 893) on 06-22-2005, 09:49 AM:

We have had problems with the clamp ring not seating the reflector to the support casting or the casting and or bulkhead supporting the casting not being square. Laser check of the reflector with reference from front and rear.....what laser tool are you using?

Posted by Demetris Thoupis (Member # 833) on 06-22-2005, 10:26 AM:

It's something out of the local market that measures distance in exact e.t.c. Its not one which fits in the middle of the lens

Posted by Thomas Jonsson (Member # 1902) on 06-22-2005, 03:35 PM:

Had the same problem a year ago when a tech was here and
replaced the old reflectors with new ones. Light wasn´t
good, and he couldn´t figure it out. So he opened up the
lamphouse again and started to "twist and turn" the reflector
and suddenly -pop- it fell into place. And there was light...

Thomas

Posted by System Notices (Member # 2357) on 06-03-2007, 09:09 AM:

It has been 710 days since the last post.

Posted by Demetris Thoupis (Member # 833) on 06-03-2007, 09:09 AM:

Ok bringing the topic back. After a lot of trials, alingotron alingment, and a lot of fiddling around I have discovered that when I open the dowser without the projector running, we have enormous amount of light in both flat and scope lenses, the bulb is dead centre and the light is amazing. Now... When we do start the projector though, and the shutter starts running, the light drops to a very dark level as if 50% less than what we was seeing. Any ideas?
Demetris

Posted by Brad Miller (Member # 2) on 06-03-2007, 01:28 PM:

Dumb question, but are you aware that the purpose of the shutter is to block the light during the pulldown action of the intermittent? Think about it for a minute.

Posted by Michael Schaffer (Member # 1204) on 06-03-2007, 01:42 PM:

Not a dumb question at all in this context since I am a little bit surprised by Demetris' observation - of course, the shutter takes away roughly 50% of the light energy - but it also has to be pointed out that the lamp should not be run for more than a brief moment with the projector standing!!! That can easily heat damage the projector head.

One thing it seems Demetris has not checked is if the working distance is correct, and if the reflector has the correct size for this lamphouse and lamp type. Or maybe he did, it is not entirely clear from the above posts. If we assume it is, then the only other factors really are that the reflector coating might be bad and then the actual alignment itself. Aligning with a laser tool is a good first step, but it needs to be checked if the image of the reflector on the screen is really centered and symmetrical - otherwise, the reflector is not properly aligned to the gate. That can be visually checked on the screen with the lens removed. Then the lamp really has to be centered in the middle of the hole, and the arc an end pieces have to be on a straight line. One good way to check all that is to move the lamp all the way forward and see that it stays centered in the middle of the hole. The reflector image also has to be perfectly round with the hole centered (remove the aperture plate to see as much of it as possible) and also, when the lamp moves forward, you get to a point where you see concentric rings appear on the reflector. These rings have to be even and appear and disappear at the same time on all sides. Otherwise, the reflector is not properly aligned.

Another great tool to help with that is the Kinoton alignment beamer, but if that is not within reach, obviously it won't help too much.

It also needs to be known how big the screen actually is, if it has top or side masking, what gain factor it has, and what the specs for this lamphouse regarding screen sizes are.

Finally, Demetris said something about the light hitting off center in the first post. When you look into the view port, you do indeed see the light off center on the reflector as you are looking at the whole assembly from an angle. But the arc itself has to be centered and straight between the electrodes, otherwise the magnet alignment has to be checked. Or were you talking about watching where the light hits in the gate area? If that appears to be off center, then there is defiitely a physical alignment issue. Using laser pointers for alignment may not be the best idea here. Visual alignment as decribed above is actually better then.

Posted by Christos Mitsakis (Member # 143) on 06-04-2007, 04:35 AM:

Is it a barrel shutter? May be the centrifugal flaps are burned and aren't opening at full during operation.
C.

Posted by Hugh McCullough (Member # 1542) on 06-04-2007, 06:06 AM:

Just a thought, but When the projector is running is the fire/safety shutter, the one you push in by hand, staying fully locked into position?

Posted by Demetris Thoupis (Member # 833) on 06-04-2007, 11:24 AM:

Ok Guys,
I've been doing this since 6 so I do know the purpose of the shutter and I do know how to properly aling a lamphouse as I've done it not only on Cinemeccanica all the old models with the original pedestals and custom made brackets to install the lamphouse on, but also on Microtechnica, Prevost, Kinoton with excellent results and I never had this issue. I allinged three other V8's with smaller lamphouse and never had this issue but what this thing is doing is very strange. The distance of the reflector to the gate is exactly as it is in the installation manual. The lamphouse and reflector is centered and I am 100% sure of that. The shutter is blocking too much light to the point of darkening the image too much. It is a conical disc shutter double bladed. I have only left the projector open for a few seconds without it running just to make a comparison. I did not just left a 4k bulb heating the projector in iddle mode. The reflector image is perfectly round and when the lamp is pulled backwards or forward then the light evenly darkens on the corners. I have never seen this happen to any of the projectors we have here before. The lamphouse is alinged based on the manual. I installed the same lamphouse on a V5 running at 2.5K and the light is far better than this one when running. The dimming of the light on the screen when the projector is running is too much and is not appropriate.

Posted by John Walsh (Member # 168) on 06-04-2007, 01:34 PM:

So, this is really a projector problem since you had the lamp on another projector (a V5) and it worked OK.

Hugh's idea regaring the fire/safety shutter is a good one .. I forgot about safety shutters because sadly most projectors today don't have them.

I never heard of a projector with a double bladed conical disc shutter. What make is it? Anyway to verify they are in sync?

Posted by Demetris Thoupis (Member # 833) on 06-04-2007, 01:51 PM:

John sorry for the missunderstanding. I meant that I installed the same type of lamphouse on an old V5 with excellent results. This was brand new from the factory. What do you mean in sync? If you mean timed correctly with the intermittent yes it is as there is no ghosting on the image.
Demetris

Posted by Michael Schaffer (Member # 1204) on 06-04-2007, 01:56 PM:

quote: Demetris Thoupis
Ok Guys,
I've been doing this since 6 so I do know the purpose of the shutter and I do know how to properly aling a lamphouse as I've done it not only on Cinemeccanica all the old models with the original pedestals and custom made brackets to install the lamphouse on, but also on Microtechnica, Prevost, Kinoton with excellent results and I never had this issue.

OK, then you don't need our input here. You already know everything. Sorry for wasting your time.

Posted by Demetris Thoupis (Member # 833) on 06-04-2007, 02:14 PM:

If I did not need an input I wouldn't be bringing up the post again. I don't like to brag but I believe I am quite competent technician and I managed to overcome a lot of issues especially with old projectors still in service. What is happening in this case is something I cannot undestand that is why I am asking whether someone has anything they might want to add. In the past, on this projector there was the Zenith X4000 vertical lamphouse and we never could get a descent light out of it so we decided to go with a new horizontal lamphouse and it was our saddness when we witnessed the same result. We have a Victoria 6 also in this theater with a 2.5 K bulb on a Zenith 3000H and is brighter than this one. I have a head from a closed cinema of a V8 on which we never had issues and I am thinking of changing the head to see if something will get better. But in the meantime I would really like some help considering that the lamphouse is alingned, with correct bulb adaptor.

Hugh, the film/safety shutter stays fully locked in position.

Demetris

Posted by Gordon McLeod (Member # 33) on 06-04-2007, 08:18 PM:

Just a wild shot in the dark (no pun intended) there is a small heat plate of waffled metal behind the apperture
I have seen a machine with an incorrect on fitted and that cut down the light dramaticaly
Also measure the width of the shutter blade and compare it to another machine

Posted by Louis Bornwasser (Member # 3063) on 06-04-2007, 08:36 PM:

Is this a double shutter projector? If so, it is possible to have more blades closed than the amount you want. In fact, you could have complete darkness if completely unlucky. Louis

Posted by Demetris Thoupis (Member # 833) on 06-05-2007, 01:22 AM:

I will check on the width of the shutter blades and also on that small heat plate of waffled metal to see if it installed correctly.
Demetris

Posted by Ken McFall (Member # 845) on 06-10-2007, 09:58 AM:

Louis the vic 8 is not made with a double shutter. It uses a standard twin blade shutter. There are two versions of the shutter blade one with slightly larger blades but that would not cause the loss of light that is being suggested.

There is one thing I did not see mentioned and that is the lamp adaptor that is fixed to the negative end of the lamp. These are needed to allow different sizeed lamps to be used. The wrong one will result in a dramatic loss of light.

Are you sure you are using the correct length adaptor?

What condition is the heat filter glass in is it very old and scratched.

This lamphouse does not use a very large sized mirror so if it's installed correctly then there will not be an issue with light passing in and onto the gate. There is no part on the vic 8 that would get in the way, apart from the safety and changover shutters.

If it is as bad as you say then it can only be something so obviouse that you're missing it as this is a very good lamphouse over all [Roll Eyes]

What about lenses....

Posted by Demetris Thoupis (Member # 833) on 06-11-2007, 01:14 AM:

The adaptor is the correct one. I even re-ordered an adaptor for the 4K bulb that is used to re-check it and it was the same as the one we had installed. I am leaning towards the shutter blades being too big. This projector always had an issue even with the old Vertical lamphouse that was used. When we reinstaleld that lamphouse on a V10 the light was superb.
Demetris

Posted by Neil Davis (Member # 2524) on 06-16-2007, 03:52 PM:

Have you tried removing the 1.85 lens and running the projector, lamp on, in a 'black ball' alignment mode?

you should have a black ring in the middle of the screen (Cathode cap) and this is in effect eclipsing the plasma ball from the xenon. do the x/y alignment so the light from the plasma is right 'behind' the black circle, then adjust focus so the ring of light is as neat as possible around the ring. Does this help things?

Posted by David Graham Rose (Member # 1450) on 06-16-2007, 04:16 PM:

Greetings All from Cambridge

I have to take issue with Kenny McEverett and his statement that this is a good lamphouse overall. It is not. It is dreadful. Put a 4kW lamp in this lantern and just watch the mirror blister.

Check the reflector coating. I bet all around the opening of the mirror there is no reflector.

Goodnight

David

Posted by Dave Macaulay (Member # 813) on 06-19-2007, 11:03 AM:

If you're sure the working distance is right and the lamp gives good light with a V10, something is probably fishy with the V8 projector.
Was the V8 a 35/70 machine? The 70mm shutter is different and passes less light in 35mm than the 35 only shutter. Try comparing it to another machine where you have good light.
Do you have the original (Galileo?) mirror? A substitute might work better with the V10's barrel shutter light path.

Posted by Demetris Thoupis (Member # 833) on 06-19-2007, 11:46 AM:

From what i recall, and from what the manager told me, this projector never played 70mm but I would find it strange if it is equipped with a 70mm shutter! My last resort is to change the projector head with one from a closed down cinema. Is the last test I will do in order to decide if the problem is finally at the projector or the lamphouse.
Demetris

Posted by Louis Bornwasser (Member # 3063) on 06-19-2007, 12:20 PM:

Barrel shutters are inherently "lossy." Louis

Posted by Demetris Thoupis (Member # 833) on 06-19-2007, 01:33 PM:

The V8 Carries a conical type shutter and not one with straight fins like the V4, V5 model. The barrel type I've only seen on the V10 model.
Demetris

Posted by Ken McFall (Member # 845) on 06-21-2007, 04:47 PM:

David I stand by my comments in that in my experience it is a good lamphouse. Simple to use and maintain and a good light.
And being a metal mirror it's not quite so painfulk if a lamp fails.....

I have not however used one with a 4k lamp in it. The max I've used is 3k and it performed very well. Good ventilation is, as with all lamphouses, a must!

Certainly if the mirror has been overheated and blistered the light output will fall.

It certainly does not deserve to be called dreadful!

The vic 8 shutter while conical presents each blade behind the gate in the same way as a 'flat' shutter and is therefore no more or less efficent. I have changed the shutter in the past to the larger bladed, 70mm, version and cannot say there was a very noticable difference in the light on screen.

Posted by David Graham Rose (Member # 1450) on 06-24-2007, 03:25 AM:

Greetings Kendall

I disagree. Everyone knows that this lantern is a heap of poo. No doubt you consider the xenon converted Super|Zenith450L an adequate lamphouse as well.

David

Posted by Ken McFall (Member # 845) on 06-24-2007, 09:31 AM:

David you are entitled to your opinion but I would appreciate it if you would use my name and not make assumptions on my behalf.

There are a number of ways at evaluating projection equipment it's 'poo' rating is not one that I am aware of.

Posted by David Graham Rose (Member # 1450) on 06-24-2007, 03:29 PM:

Greetings Kennilworth

I am indeed entitled to my opinion, and will have my say whenever possible. Having experienced your performance in the box and on installations you will no doubt be aware ofthe poo rating - a scale on which you invented yourself!

From Cambridge

Goodnight

David

Posted by Stephen Furley (Member # 1277) on 06-24-2007, 03:55 PM:

quote: David Graham Rose
I disagree. Everyone knows that this lantern is a heap of poo.

David; I don't know that; indeed, I don't know anything about this lantern; I've never used one, and I'm not sure if I've ever even seen one. Could you please be more precise as to what you don't like about it.

Posted by Ben Wales (Member # 92) on 06-24-2007, 04:15 PM:

quote: Stephen Furley
David; I don't know that; indeed, I don't know anything about this lantern; I've never used one, and I'm not sure if I've ever even seen one. Could you please be more precise as to what you don't like about it.

They were basicly a Xenon conversion Lamphouse from a Arc, loads of Odeon's Cinemas had them as well the Plaza Cinema in the West End, London had some up to closure.

David: are you expressing your views as a Projectionist or a Cinema Service Engineer?.

Perhaps we could have your views on the Peerless Xenon Lamphouse conversions [Eek!]

Posted by Ken McFall (Member # 845) on 06-24-2007, 06:20 PM:

David,

clearly you have some problem with me. As I don't know you or have ever meet you I'll reserve my opinon of you until I have a basis for one. Your ignorance will not cloud that opinion when I form one.

All I have done is to express an opinion on the topic and don't feel I've earned the ignorance of your comments and have certainly not been offensive.

I at least can base my opion of this lamphouse on it's istallation, use and repair.

The evaluation of any peice of equipment is not only based on its technical excellenace but on price and overall ease and cost of ownership. The 'Best' is not always the best for every situation.

Ben, I think you may have a different lamp house in mind. The 4000 is a purpose built xenon with fixed metal irror and offset extract duct on top. Bright blue removable top cover. Quite a slim compact body similar to one of the strong supalumex lamphouses I think.

Posted by Gordon McLeod (Member # 33) on 06-25-2007, 06:56 AM:

Most of the horizontal lamphouses in the zenieth line give very good light but they are fussy on alignment and on cooling
the only ones I have had blister the reflector was incorrect alignment and lamp focus

Posted by Ken McFall (Member # 845) on 06-25-2007, 11:58 AM:

Gordon the thing I like about this lamphouse is that the press studs give easy quick access and the whole top comes off which makes for very easy maintenance.

Unfortunatly many people overlook cleaning the intake fan and it becomes clogged with dirt quite quickly. When that happens the lamphouse can easily overheat and damage the mirror. This is the case with many lamphouses today that are very compact and is not a design fault as such. Hook up a good extract and this lamphouse will provide years of good service.

Posted by John Wilson (Member # 269) on 06-25-2007, 12:31 PM:

quote: David Graham Rose
Greetings Kendall

quote: Ken McFall
David you are entitled to your opinion but I would appreciate it if you would use my name and not make assumptions on my behalf.

quote: David Graham Rose
Greetings Kennilworth

David

Don't show your ignorance. It does you an injustice.

Posted by John Walsh (Member # 168) on 06-25-2007, 01:04 PM:

A few more ideas I thought of, but nothing big.....

The V8 has both a fire-safety "drop" shutter and a zipper-style changeover shutter (in addition to the regular spinning shutter.) The fire-safety was used also as the changover on earlier V8 models. I've seen where one of the two rivets holding the round disk to the bracket sheared, and the disk would hang down in the light beam, partially blocking it. (This is still a problem today with V5's.)

The zipper-style uses a flexible cable to push-pull the zipper open/close. The cable gets loose at either end, and doesn't travel the entire intended distance, again partially blocking the light. I notice that V8 zippers really wack hard when opening or closing and tend to get bent, loosen, etc; I never knew if that was how they were designed, or if it was the result of US/Italy voltage differences.

With xenon bulbs (Osrams) I found a few where the ferrules that clamp the metal bulb ends were loose, allowing the metals ends to slide, throwing off the bulb-to-reflector focal point. So if the bulb is just placed in without adjusting the Z axis, the focus was wrong.

I just send Brad a ZX4000 manual I found. Probably too old to really help anyone, but I guess you never know....

Posted by Stephen Furley (Member # 1277) on 06-25-2007, 01:20 PM:

quote: Ben Wales
They were basicly a Xenon conversion Lamphouse from a Arc, loads of Odeon's Cinemas had them as well the Plaza Cinema in the West End, London had some up to closure.

Ben,

Sounds like you're talking about the huge things, basically rectangular in shape, but with rounded corners, and with a smaller section at the back; the Odeon Leicester Square had them when they had the Vic Xs, and I think many other Odeons had them on Vic 8s, but I don't think those are the ones that Ken was talking about.

Posted by Demetris Thoupis (Member # 833) on 06-25-2007, 01:24 PM:

He had the same type of lamphouse installed on a V5 with 2.5K bulb and no problems. I don't agree the statement that its a "pooh" lamphouse. The light does not match the Kinoton though but the newer lamphouse of Cinemeccanica are really advanced.
Demetris

Posted by Peter Hall (Member # 695) on 06-28-2007, 02:27 PM:

Ben silly billy

The seaside air must be getting to you. The Plaza lamphouses were
1a 2a - Xenex 1s however stripped out and with Bernard Bentley conversions in them
1b 2b (on the DP70s) - great big old Cinemecannica carbon boxes with again Bernard Bently conversions in them

These REALLY could be described as poo or any other form of excrement.. but hey, what do I know ?

Posted by David Graham Rose (Member # 1450) on 06-29-2007, 01:35 AM:

Dearest BennyBoBo

You sought my opinion on the Peerless Magnarc Xenon conversion aka the McCannLightbox. There are two things you can do with Peerless conversions. The first is to convert them to a drinks cabinet - they look very good with the correct wall paper or do as I often do.

This is a Peerless that I stripped out of the ABC Nottingham when it closed.

Quote Kendall again;

"David,

clearly you have some problem with me. As I don't know you or have ever meet you I'll reserve my opinon of you until I have a basis for one. Your ignorance will not cloud that opinion when I form one."

Well Kendrick. Cast your mind back. We all remember the old Odeon Disney/St.Martin's Lane aka Lumiere do we not Le Ken Rouge? I seem to remember your own ignorance clouding your judgement there!

Good Morning from Cambridge

David

[ 06-30-2007, 03:51 AM: Message edited by: David Graham Rose ]

Posted by Ken McFall (Member # 845) on 06-29-2007, 10:35 AM:

David you seem to have aproblem with what was a simple request. You know my name please use it or don't continue.

As for the past I can't recall you at all and if you can't contain your ignorance whilst on this site then I don't care to.

I really don't think it's worth continueing this rather pathetic saga.

Regards

[ 06-30-2007, 07:23 AM: Message edited by: Ken McFall ]

Posted by Ben Wales (Member # 92) on 06-29-2007, 06:29 PM:

quote: Peter Hall
The seaside air must be getting to you. The Plaza lamphouses were
1a 2a - Xenex 1s however stripped out and with Bernard Bentley conversions in them

Peter: good to see you are back on this site and yes indeed those Zeniths were a Bentley Conversion and it was late when I posted about the 450, rather than about the 4000!

quote: David Graham Rose
You sought my opinion on the Peerless Magnarc Xenon conversion aka the McCannLightbox. There are two things you can do with Peerless conversions. The first is to convert them to a drinks cabinet - they look very good with the correct wall paper or do as I often do.

Davie-Gray-Rosie (Professor of Cinema [dlp]

)
We don't use real names here.

What ever get's you excited having a Peerless Lamphouse in your garden or having it decorated [Smile]

Posted by Troy Hilsman Powell (Member # 4326) on 06-29-2007, 07:22 PM:

I know that this might sound dumb but I did have an experience with the V8 and found that the dowser can get somewhat lazy and will hang down a little bit so you have to adjust the pull up solinoid by adjusting it to get rid of the pull up slack.The electric dowser is very close to the light beam anyway as it is and is caused from wear on the linkage.Hopes this helps.Don't give up.

Posted by David Graham Rose (Member # 1450) on 06-30-2007, 03:50 AM:

[ 06-30-2007, 05:36 AM: Message edited by: David Graham Rose ]

Posted by Brad Miller (Member # 2) on 06-30-2007, 04:41 AM:

Greetings David in Cambridge.

You will be removed from the forums if you continue this nonsense of addressing another member with silly names after he has very nicely asked you to use his proper name. Judging by your picture you are a few decades too old to be acting so immature.

Posted by System Notices (Member # 2357) on 08-11-2008, 01:32 PM:

It has been 408 days since the last post.