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Barco Cine 8 Green spot on shutdown

nick2005

Standard Member
I have a Barco Cine 8 with LC tubes that has just developed a couple of faults.

One is that when shutting down the projector a green spot or goup of spots appear to fly down from the top of the screen and then fade out. There is no evidence of any burn on the green tube.

The other is that in scenes of low average ambient light noise appears on the screen almost like a light grey flickering accross the entire image. This happens on port 3 & 5 using different sources.

Nothing has been changed in the setup of the projector or its inputs - I have the impression that something is slowly failing.

Does anyone have any ideas or suggestions?
 

Tom.W

Active Member
If it only happens on Green then it could be the video amplifier chip on the Green RGB amp or a possible high short in the CRT tube.

Try swapping the video amps and see if the same trouble follows to the swapped RGB amp.
 

Roland @ B4

Active Member
I would keep an eye on this but to an extent they all do it.
So long as the spot is not bright or sharp and last for any length of time I would not be overly concerned.
It does mean that the EHT is not shutting down fully before the scan circuits.
 

nick2005

Standard Member
Thanks for the input and suggestions, if the EHT is not shutting down properly would this also tie in with the flickering apparent on the screen in low light scenes?
 

Roland @ B4

Active Member
Something in my distant brain says that a couple of the surface mount capacitors on the Focus board cause this. It is related to the ABL and was known for a while as Candle Flicker.
Most noticable during the credits rolling at the end of a film
 

nick2005

Standard Member
Ok I did a bit more testing - it appears that the worst of the noise is on the green tube and also the green tube is showing retrace lines.

Swapping the boards at the back of the tube makes no difference - even swapping the signals with the blue tube makes no change. So I tried swapping the EHT connections off the splitter but the green tube still shows a lot of noise and retrace lines.

I suspect the green tube is influencing the others as the noise is most apparent on green looking down the lenses, also the green tube shows a bright streek during shutdown starting at the EHT input.
 

Tom.W

Active Member
Sounds like you have a G2 short in the Green CRT gun.That's what is causing the fireworks on shut down. I had the same thing on my BD 808s Red CRT. I used it for about 2 years without causing problems. I finally bought the Sencore CR-7000 and it cleared the short. Read the Google doc attached....

Powered by Google Docs
 
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nick2005

Standard Member
I was afraid of that - looks like the short is influencing the other tubes as there is a lot of background noise on the green image (looking directly at the tube).

Can I get this tube repaired - otherwise does anyone have a good P16LXV43HKA green tube?
 

Tom.W

Active Member
I doubt the this should effect the other tubes. The retrace lines are caused by the short. You can check for a possible short with an ohm meter.
 

nick2005

Standard Member
I can check for short circuits - which pins should I be checking or do you know the pin out?

I have not checked the tube with no input - but with a dim scene from the DVE DVD and a 20% bar in the middle the R & B tubes show the very dim brightness bars but the green tube is glowing too brightly to show these bars. To see the green glow you do have to look down the lense so it is not superbright.
 

nick2005

Standard Member
Hi Tom,

Yup that is the tube number it is from a LC Barco Cine 8 from late 2003. I checked the label on the side of the tube itself.
 

Roland @ B4

Active Member
That sounds like a fast phosphor simulation tube. Good news is it would 3d better then most
 

Tom.W

Active Member
Did you already find the pinout on the tube ? Should be the same as a 180DVB22.

Filament on pins 9 and 10 (you will see a short there)

K (cathode)=pin 8

G1=pin 5

G2=pin 6
 

nick2005

Standard Member
Hi Tom - thanks for the pin out info, not being able to easily see the pins at the back of the tube how do identify pin 8? This unit is ceiling mounted so with the cover hanging down things get a bit tricky!!

Also if I test the tube using a multi meter I am assuming that pin 6 should appear as open circuit to any other pin including the EHT input?

I read somewhere that the tube could be fixed by tapping the gun end with a small block of wood?

Looking at the sencore info it appears that this device could blast the short out of the tube?
 

Tom.W

Active Member
Take a look at this diagram. It should be the same as the P19LCPO7. Pin 1&2 in the key slot then count clockwise looking at the rear of the tube. As I said the Sencore cleared the G2 short and it is possible gently tapping the tube neck around the gun may solve the problem if your very very lucky....
 

Tom.W

Active Member
You can only upload the same file once ??????????????

See the very bottom of the service manual sticky.........
 

Decibel1962

Standard Member
This is a crt socket.
I hope it help you for pinout identification :)
Sorry for my english :rotfl:

pinout808.jpg
 

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