CurtPalme.com Home Theater Forum

[MeV]

Hi

I've got a problem with my Marquee. It begans after installation of new bellows I purchased from nashou. The new glycol turned after some weeks into a brown liquid like cola So I changed the glycol in the hope that all residues are gone or at least most of them. This glycol got discolored too. So before I waste a third charge glycol, had anyone this problem and got a solution for it? I carefully cleaned all three bellows with hot water and soap before installation as described.

[redfox001]

Nope I got the same problem. I also cleaned with water and soap. I gave up and bought a new tube

[cmjohnson]

You need to thoroughly clean the whole LC chamber and SEAL all the surfaces in it (other than the glass, of course) with something very chemically inert and very NON-porous. Very high temperature (VHT) epoxy paint works well. Flat black is best. You always want to reduce all stray light in any optical system. If it's not part of the projected image, you want it to never leave the optics. That's why optical hardware is always black.

[Curt Palme]

I believe the discoloration comes from the rubber washers under the fill screws. Change both the washers and the fill screws. I am out of the screws, but have the washers. I've ordered the fill screws, but they are taking forever to show up.

[Curt Palme]

I believe the discoloration comes from the rubber washers under the fill screws. Change both the washers and the fill screws. I am out of the screws, but have the washers. I've ordered the fill screws, but they are taking forever to show up.

[Tim in Phoenix]

[Nashou66]

Yeah I don't think its the bellows. I cut one up and let it soak in glass filled with glycol for over a year. Its the Chambers them selves I think. Like Curt said. I think instead of filling the chambers through the fill holes I would stand the tube on end and fill from the hole of the removed C-Element. Then put the C-Element in. But First fill those fill holes from the inside with
clear silicon. I think he exposed metal of the threads reacts with the Glycol. When they are new its not an issue but the old screws
that most likely are corroded have tainted those threads and the dirt grows like cancer.

Nashou

[redfox001]

I used the new Curt screws and washers


All I know is that I had sweating bellows, nothing more. Than I changed the bellow (and the screws) for a new one and in a day it turned brown. Than I washed the bellow and the chamber and everything new glycol and it took a few months to go brown again. It is strange that it turned brown so fast if the reason was that I somehow made a scratch somewhere that I did not see by the way. So most likely the bellow or the screws. But I did not wash the screws

Other possibility would be I scratched the chamber. But than why did washing the chamber do anything on the scratch?

Other possibility there is a contamination. But than all my Barco's would be contaminated like hell too but no brown glycol.

[redfox001]

But perhaps replacing it a third time might take some years for it turns brown again? I did not try yet.

[Curt Palme]

What I've found is that if the set is ceiling mounted, the glycol will work its way down the fill screw threads, where the rubber washer prevents leaks. Over the years, the washers become soft, either from the glycol or just due to age. When you take down the projector, you then allow the projector's glycol to drain from within the screw/washer assembly, and my theory is that the tiniest amount of glycol/rubber mixture will turn the glycol brown, as the glycol must move within the LC chamber as the set is being used, due to heat.

In many LC chambers that I've changed the bellows and screws over to stainless, I've seen the black rubber goop in the threads of the old screws (I wiped them off with paper towel), and also saw it in the threads of the LC chamber itself. I take cotton swabs to clean out the crap from the threads (it usually takes a few Q tips), then reassemble everything once everything is clean.

that's my theory anyway, but I'll bet it's pretty accurate.

[Curt Palme]

What I've found is that if the set is ceiling mounted, the glycol will work its way down the fill screw threads, where the rubber washer prevents leaks. Over the years, the washers become soft, either from the glycol or just due to age. When you take down the projector, you then allow the projector's glycol to drain from within the screw/washer assembly, and my theory is that the tiniest amount of glycol/rubber mixture will turn the glycol brown, as the glycol must move within the LC chamber as the set is being used, due to heat.

In many LC chambers that I've changed the bellows and screws over to stainless, I've seen the black rubber goop in the threads of the old screws (I wiped them off with paper towel), and also saw it in the threads of the LC chamber itself. I take cotton swabs to clean out the crap from the threads (it usually takes a few Q tips), then reassemble everything once everything is clean.

that's my theory anyway, but I'll bet it's pretty accurate.

[redfox001]

Ok that could explain it. Than it is not the bellow but the rubber from the old screws. I did not clean the holes more than with water with soap.