CurtPalme.com Home Theater Forum

[PaulB]

Guys,
Looking into the green tube, I can see white stuff in the LC chamber sitting on the bottom. Any idea what it is ? Its a bad out of focus picture I'm afraid but I've circled the offending objects. Is this fungus or just crap lying on the bottom? Anything to be worried about?

Also, there is some sort of whitish powder stuff lying between the tube housing, reminds me of decayed aluminium or something? Again, any ideas, anything to be worried about?






Thanks guys,
Paul

[PaulB]

Better picture of the green LC chamber (ignore the yellow dots) does that show the gunge on the bottom of the chamber better?

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[cmjohnson]

It's due to some corrosion of the aluminum in the chamber. It seems like it always happens eventually.

The aluminum chamber pieces are hardcoat anodized when they're made, and this is a very tough and durable finish,
but eventually, any weak spot allows glycol to penetrate to the aluminum and then a little corrosion begins.

I don't know of a quick, easy, or cheap fix. Dumping the glycol and cleaning the chamber thorougly and then refilling it
will give you a few more years of clarity, but eventually, the muck comes back. But it has to be pretty bad to have any significant
effect on the picture.




CJ

[PaulB]

Many thanks for the prompt and helpful reply.

Having done a further search based upon your reply, I think I'm pretty much up to speed with the problem. Like you say, I don't think its a real issue until it gets bad but having closely examined the chamber I'm pretty sure that the green C-Element has a smear/track on the inside (it casts a shadow on the tube) which will need cleaning.

To be on the safe side I'm inclined to buy a new C-element and a new bellows just in case - any idea where thes may be purchased and indication of cost? VDC?

Many thanks,
Paul

[draganm]

[PaulB]

My thanks to both of you for your replies.

Just to confirm if I may, Gina is the contact for bellows (as well as C-Elements)?

I think changinging the bellows is quite a task, even the experienced guys here seem to talk about it in hushed tones

I think that I'll stick to cleaning out the chamber and cleaning the C-Element (if indeed the smear/track issue is the C-Element) and take it from there depending on how things go. Is there a method to cleaning the C-Element? Presumably I'll need to rub it to clean it - any do's or don'ts?

Thanks,
Paul

[igroucho]

For some very strange reason the crt business is completely neglecting basic knowledge that permitting ANY contact between iron and aluminium in an acid environment (= glycole) is going to lead to massive corrosion. In the ship industry for ex one wouldn't even think for a sec about this: whenever there's need for bonding of aluminium only acid fast steel will do. And if there's any electric currency involved the problem aggravates immensely. So why these lines: the screws for the filing/venting holes in crts are just plain iron. Thou small they will intiate corrosion! And there you have your "fungus".
Thus I changed mine to stainless steel ones!

[cmjohnson]

Yes, that's true. There's often a line of gunge leading down the C element or CRT face which is, not at all coincidentally, directly below the
vent screws.

Stainless is one way to help. Another is to siphon out just a LITTLE bit of glycol after filling, just enough to get the screw holes clear,
and put in a drop of silicone sealant before putting the vent screws back in. It'll coat them and protect them against the glycol,
at least in theory.

Changing the bellows is NOT a DIFFICULT job. It's just one that takes time and attention to detail. And most importantly of all,
DON'T RUSH IT. Particularly when it comes to the silicone rubber sealant you use, let it take at least a full day to cure before you
think about putting the glycol in. Rush this, and you WILL get leaks.


CJ

[PaulB]

Thanks guys.

I think I will change the screws to stainless steel ones, thats a quick and easy fix. I will though look to change the bellows at some point. I'll wait until some kind soul does a "How To" on it though. By my reckoning the bellows/corrosion problem is likely to increase with age and a bellows change will become necessary for more and more folks with aging marquees. I'm keen to give it a try but not keen enough to be at the front of the pack of "bellow fixers" (bit like life really, leaders and followers!).


Anyway, I'm very reassured by your insightful comments and am grateful for imparting your experience to a marquee noob!

I'm about to order some Glycol from Curt and do the LC chambers when I receive it along with the screw change. I intend to be VERY careful with the bellows but may just order a couple just to be safe

Again, many thanks for your help, much appreciated!
Paul

[cmjohnson]

I have changed a number of bellows out. It's not tough. It only gets tricky if you're trying to save the bellows that's already there
and it's been siliconed down.


CJ

[armstrr]

i might have a 9500lc that needs the gycol changed/flushed. has someone documented the procedure? i assume the magnetics can stay on, correct?

if it is worth changing the bellows, what is the cost of them? thanks!!

[armstrr]

i might have a 9500lc that needs the gycol changed/flushed. has someone documented the procedure? i assume the magnetics can stay on, correct?

if it is worth changing the bellows, what is the cost of them? thanks!!

[Curt Palme]

I've never done it, and having changed my first tube in a MArquee LC housing, I'll leave that to VDC from now on. I managed to break the (dud) tube in the housing, and it's a really messy, time consuming job.

[Curt Palme]

I've never done it, and having changed my first tube in a MArquee LC housing, I'll leave that to VDC from now on. I managed to break the (dud) tube in the housing, and it's a really messy, time consuming job.

[PaulB]

I left all the magnets on but removed the neck boards (primarily to inspect them but it also reduces the weight).

I drained all the glycol out using a syringe with some heat-shrink attached to the needle inserted into the chamber via the fill-holes. Once drained I flushed the chamber a couple of times with warm water with just a hint of washing up liquid in it (again using a syringe to half-fill the chamber each time followed by shaking of the tube with the fill screws replaced!). Immediately after that I flushed it with distilled water 4 or 5 times and then left it to dry (distilled water leaves no mineral deposits/streaks when dry unlike normal tap water). All this flushing removed most if not all deposits / corrosion globs / old silicone cuttings etc.

If the LC chamber and / or back of the C-Element still looks dirty only then did I remove the C-element for cleaning (C-element removal is well documented on this site). I managed to remove one C-element without the need to destroy the bellows, on the other tube I had to cut open the bellows which obviously meant I had to install a new one. Removing the element allows you to clean it as well as fully clean out the LC chamber and clean the tube face (one of my tube faces was quite surprisingly dirty as was the C-element, both were covered in a light film of sooty-like stuff that wasn't apparant when looking at them through the coloured C-element).

Once cleaned, the C-element and/or new bellows can be reinstalled and the chamber filled with new glycol (or filter the old stuff using coffee filters if it looks usable i.e. if its turned yellow then don't use it). It just takes time and care. Do a search on bellows and you'll piece together all the necessary do's and don'ts.

Hardest part was draining the glycol, man that almost gave me blisters on my finger with all the syringe pulling!

This was the first time I had attempted anything like this. It was straight-forward and a lot easier than I'd thought. Just make sure you get all the right kit before you start. Bellows are $50 direct from VDC Edit - this price fluctuates, one day its 50 bucks, next its 100 !

[psilvest]

I bought two bellows from VDC last summer and they were 100 $ each..

Has the price decreased?


Pier

[Nashou66]

Paul glad to see your having fun working on your marquee.

Athanasios

[PaulB]

[PaulB]