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Discussion Starter · #1 ·
I was checking out an ECP-4100 that supposedly had a "problem". What I found was that the Green and Blue tubes had what appears to be a circular out of focus area in the center of the Green tube and slightly lower on the blue tube. It appears more of a blurry halo than really being out of focus.


Looking into the tubes and using the electronic focus control, it appears to me to be on the backside of the front glass on the tube. When I removed the tube, figuring to drain the fluid and remove the front glass to clean it, I THEN COULD NOT "SEE ANYTHING WRONG SIMPLY BY LOOKING.


My question to someone who has had experience with this before is this, even-though it shows up when looking at it when the projector is running, it it possible NOT to be able to see it with the pj off.


Maybe it's because of the age of the 4100's 07MS tubes and the fact that most of the projectors I worked on were never more than 5 or 6 years old max, I have really never have seen this problem before. Some people call it "fungus", which I don't believe it really is and some claim it's caused by a combination of the original gasket, the glycol and heat. Whatever causes it, I am now beginning to wonder if when it first begins, it is causing some people to think it has something to do with optical or electronic focus.


Bruce
 

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Sometimes it is very hard to see except in the image.

It can simply appear as a haze and you may have to hold the tube at the right angle in the right light.


Usually though you can see it. If you've looked left right up down and sideways in various light and still don't even see a haze then maybe not, but it's a sneaky hard to spot problem sometimes for sure.


I bet it is on the tube face itself, not the inside of the outer glass. Look at the phosphor "grain" and look for anything in the way. It may be exactly the same color as the phosphor, except on the wrong side of the tubes glass.


Troy
 

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Discussion Starter · #3 ·
Thanks Troy,


I held it at every angle possible and looked with and without a flashlight, however, when the pj was on, I could swear as I turn the focus, it was sharp behind the haze.


It would sure be a pity to "ruin" 2 more otherwise perfect 07MS tubes by cutting the original gasket. Oh well, it's worthless with the haze and I can't find ANY other cause for it. I would have thought the "fungus everyone was talking about should be some kind of "growing" black slime.


If anyone else knows another reason, let me know before midnight, when I start the cutting open ceremony.


Bruce
 

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It will be very hard to see while the fluid is still in the tube and the tube is not projecting. If it is fungus, and I suspect it is, it will become obvious when the fluid is removed. With the fluid removed the gunk remains on the glass. Be very carefull when you are removing the glass as it will break with little effort. Save the coolant from the green tube. Filter it and re-use it. You can top it off with clear. The blue is not color corrected so you can re-fill that one with new clear fluid. There are a few posts here outlining the proceedure. This is common on Sony 07MS and SD-187 tubes.


Chip S.
 

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I hate to be a wet blanket, but do not reuse the fluid - refill with clear. The 'fungus' isn't fungus at all, but a crystal formed by the interaction between diluted ethylene glycol (an electrolyte) and a dissimilar metallic junction (cadmium plated 'passivated' - LOL - steel screws and aluminium alloy) which creates a weak battery, and attacks the aluminium - which forms crystals on any surface.


By replacing the coolant, you reduce the acidity of the glycol (due to less water in it - glycol is hydroscopic and absorbs water from the air).


The colour correction on 07MS tubes does naff all anyways.


Make sure you use a very sharp (ie new) blade to remove the glass and you should be OK - also, allow the silicon sealant to dry for a week before refilling.


A well done tube with new coolant should last as long as the old one, reuse the coolant and you may see the fungus back sooner than you expect.


Cheers

Heath Young
 

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It is fungus, and every post has covered what I was going to say..:)


Curt
 

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Discussion Starter · #7 ·
Thanks all for your help !


heathyoung,


I think you're right, I'll use "new" fluid. I have a couple of containers of RCA fluid that I used to use in rear screen tv's. It 70% glycol and 30% glycerin. They're new bottles in plastic containers wrapped in plastic and in a box. Because I'm sure it's at least 6-7 years old and has been here in Florida, I sure hope it can't absorb moisture in spite of it's packing. Everything in Florida goes bad. Rubber drive belts turn to mush over time from the humidity. This occurs even though everything is air-conditioned.


Bruce
 
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