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» Film-Tech Forum   » Operations   » Digital Cinema Forum   » Barco lamp alignment issue (Page 1)

 
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Author Topic: Barco lamp alignment issue
Pratheesh Chandran
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From: India
Registered: Dec 2018


 - posted 01-06-2019 05:15 AM      Profile for Pratheesh Chandran   Author's Homepage   Email Pratheesh Chandran   Send New Private Message       Edit/Delete Post 
Barco dp-2k 20c projector shown only .20fl after changing lamp.after align x,y and z axis its shown only .40 fl max. brightness is low.seems it s lamp house prblm..any other options??

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Marco Giustini
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From: Reading, UK
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 - posted 01-06-2019 05:32 AM      Profile for Marco Giustini   Email Marco Giustini   Send New Private Message       Edit/Delete Post 
The brightness sensor needs to be calibrated regularly. If it was never calibrated, chances are it just doesn't read anything meaningful.

Was the old lamp showing similar values?
Do you have another lamp to try?
Is the lamp fully seated on the socket? It's a common issue where the lamp end does not sit inside the gaps. Loosen the lamp bolt and carefully rotate the lamp in both direction, you should be able to see a very little rotation allowed before hitting a stop. You can also inspect the socket via the side window, through the mesh.
Are you reaching the end of any of the adjustment axis?

How does the brightness look on screen?

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Dave Macaulay
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From: Toronto, Canada
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 - posted 01-06-2019 08:43 AM      Profile for Dave Macaulay   Email Dave Macaulay   Send New Private Message       Edit/Delete Post 
Is the screen actually that dark? That would be very very dim. The number shown during alignment is arbitrary and usually set to actual screen brightness when doing color calibration so that you can use the CLO system to automatically maintain brightness as a lamp ages.
If it is super dim on screen:
Is the CLO reading on the graph still going up but you run out of X movement (the centre knob)?
If so, the lamp cathode adapter pins may not be in the notches, but that's a noob mistake and unlikely for experienced staff. The other noob mistake is to have the anode end hanging, not in its socket.
The swivel bushing the cathode adapter seats into can and does slide out of its seat a bit, causing the same effect. You can see it with the lamp out, the face of the bushing outer shell should be roughly flush with the aluminum housing. You need to remove the cathode mount assembly - the sliding metal tube - to access the bushing and tap it back in.
Your new lamp may be defective. Check that a different lamp, even the just removed one, will give decent readings and peak during alignment.

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Monte L Fullmer
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 - posted 01-07-2019 12:48 AM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
I sometimes do the old "Looney Tunes" coarse bulb focus by bringing up the white screen display in the test mode and align the bulb where the screen had even field of light if I can't do it in the Communicator.

I bet the 5mm allen screw wasn't put back in on the cathode end and the bulb moved way far forward in the module.

Or, the screw was put back in, but the pins on the cathode adapter missed the slots in the castling nut on the other end so the bulb can't be locked back into position, where you'll never get the right focus.

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Pratheesh Chandran
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From: India
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 - posted 01-07-2019 02:12 AM      Profile for Pratheesh Chandran   Author's Homepage   Email Pratheesh Chandran   Send New Private Message       Edit/Delete Post 
same issue for the standby lamp..when turn x axis the black metal part moves and fl turns low ( .40 to .20) but when x axis released there is no movement in the above part and it stuck ..after turn x axis opposite direction and pull back the metal part with hand the fl showing increasing value( .20 to .40 )..and also noticed increasing and decreasing brightens respectively on the white test pattern.

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Marco Giustini
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From: Reading, UK
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 - posted 01-07-2019 04:11 AM      Profile for Marco Giustini   Email Marco Giustini   Send New Private Message       Edit/Delete Post 
.20 or .40 is still nothing.

Are you suggesting that the X axis adjustment only works in one direction and you have to pull the lamp socket by hand to move it? Those controls have some play, but if the socket moves in only one direction, then you may require some parts.

I never inspected that mechanism but I don't think you should be able to move it by hand.

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Pratheesh Chandran
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From: India
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 - posted 01-07-2019 04:38 AM      Profile for Pratheesh Chandran   Author's Homepage   Email Pratheesh Chandran   Send New Private Message       Edit/Delete Post 
YES. the X axis adjustment only works in one direction I have pull the lamp X Adjustment part by hand to return the original position (for max fl). may be that part is malfunctioning .

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Dave Macaulay
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 - posted 01-07-2019 05:47 AM      Profile for Dave Macaulay   Email Dave Macaulay   Send New Private Message       Edit/Delete Post 
Sticky cathode tubes are fairly common, if you take it out and clean the tube and bore then add some lube (a bit of oil) it loosens up.
If you pull the tube all the way back (there should be a stop but don't screw the nut all the way off) and it still would be brighter further back, look for the bushing issue or the pins issue... and confirm the adapter is screwed all the way down on the lamp.

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Pratheesh Chandran
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 - posted 01-07-2019 11:01 PM      Profile for Pratheesh Chandran   Author's Homepage   Email Pratheesh Chandran   Send New Private Message       Edit/Delete Post 
I am sorry i write a mistake...i mean z axis .. the part i pull back is the black metal attached to z axis..today i loosen the z axis screw and pull back the metal part and tight the nut..now its gave better around 1.10 fl...but a little flickering in the screen..

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Marco Giustini
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 - posted 01-08-2019 04:13 AM      Profile for Marco Giustini   Email Marco Giustini   Send New Private Message       Edit/Delete Post 
Z axis getting stuck is common. As Dave said, put *a little* lubricant (high temperature) on the pins where the adjustment runs and also between the rod and the washers, to remove that "grinding" feeling. Pulling it by hand, carefully, also works.

Again, the footlambert reading on the communicator is relative to a calibrated value. If it was never calibrated - or the calibration file somehow got lost/corrupted - then you will read random values. I ask you again: how does it look on screen?

Try this: calibrate the light meter using a random higher value - say 10 - and then try adjusting the lamphouse again. Save on a different file just in case and make sure it is active when you calibrate again. I had a situation once where the light sensor was miscalibrated and all it would read was 0.x.

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Pratheesh Chandran
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From: India
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 - posted 01-08-2019 05:44 AM      Profile for Pratheesh Chandran   Author's Homepage   Email Pratheesh Chandran   Send New Private Message       Edit/Delete Post 
screen brightness is too .its looks like 1000 w lamp output :-)

Are you suggesting in normal mode Calibrate current light output to 10 .. and save it ..ok i will try.

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Dave Macaulay
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 - posted 01-08-2019 12:39 PM      Profile for Dave Macaulay   Email Dave Macaulay   Send New Private Message       Edit/Delete Post 
Yeah I get confused by X,Y,Z too.
Again, if the Z axis (not X...) adjustment moving back (unscrewing the nut and pulling on the tube) increases the reading and it's still increasing it when the tube can't move further out: something is wrong. Maximum reading should be reached with the adjustment a few mm shy of fully out.
Possibilities:
- the lamp cathode adapter (brass thing) is not screwed on all the way
- the adapter pins are not dropping into the slots in the tube, or the tube is damaged and won't let them all the way down
- the swivel bushing has shifted out in its bore
- the lamp is defective

I would take the lamp out, confirming the pins are seated once the allen screw is loose - the lamp should only rotate a tiny bit when the pins are in slots. Then confirm the adapter is screwed down flush with the lamp cathode end. Then take a look at the inside end of the lamphouse cathode mount with a flashlight: in the centre is the swivel bushing, shiny centre with a dark ring. The ring must be flush or below the aluminum cathode tube, all the way down in the centre bore.
If all that looks good, replace the lamp with a new or used one. If the lamp has gone black, or the anode electrode is deformed, or either electrode is a weird colour, that's a sign of a bad lamp as well.

To push a slipped bushing back in you need to take the cathode tube out and hammer it back in, using something that won't damage it. If you need to do that, check that the bushing ball swivels freely - if not, put a drop of oil around it then twist it around with a screwdriver to loosen it up. The tube may be really hard to pull out as the "fingers" can get bent out, it will pull out though with force and twisting (once off the alignment shafts and threaded rod). You need to take the shiny cap thing off and remove the spring and cable end first as well as the thumb nut and washer, plus there should be a clip on one of the alignment shafts to limit its rearward movement.

Assuming the reading was calibrated and you really have very poor screen brightness I would not change the LSC file calibration for an active macro for flat or whatever. You can make a new macro (name it LSC or something) with only the one command, changing the LSC calibration. Make it 20 or so, then execute a normal macro followed by that macro. This gives you a number that's reasonable and the graph will show a decent change as you adjust the lamp. Next time the real macro executes it will go back to the existing LSC calibration.

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Pratheesh Chandran
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 - posted 01-08-2019 10:07 PM      Profile for Pratheesh Chandran   Author's Homepage   Email Pratheesh Chandran   Send New Private Message       Edit/Delete Post 
yes ..i will try ..

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Pratheesh Chandran
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From: India
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 - posted 01-09-2019 03:41 AM      Profile for Pratheesh Chandran   Author's Homepage   Email Pratheesh Chandran   Send New Private Message       Edit/Delete Post 
its showing better results.. when i loose the nuts ..fl changes and showing better values..i think the cathode of lamp not correctly suite in the socket..

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Leo Enticknap
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 - posted 01-09-2019 07:45 AM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
The socket into which the cathode end of the lamp sits (through which the Allen-headed bolt goes) has recesses into which the locking pins on the shaft of the lamp have to engage. Holding the anode end of the bulb and the socket assembly from the back, rotate the bulb gently until you feel the pins go into the recesses, then thread and tighten the bolt.

If the back of the bulb isn't seated properly, you'll feel that it's too tight when you fit the UV blocker at the front of the lamphouse (unless you're using the wrong adapter).

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