CurtPalme.com Home Theater Forum

**ecrabb** · Posted: Sun Feb 20, 2011 5:53 pm Post subject:

**ecrabb** · Posted: Sun Feb 20, 2011 5:59 pm Post subject:

REGNAD · Joined: 15 Oct 2006 Posts: 169 Location: RICHMOND VA

not expensive, but dont have it. working on selling some gear now. do i need to consider replacing the glycol when i do this? i assume ill need some to top things off?

Zebu Fellenz · Joined: 21 Dec 2006 Posts: 2548 Location: Phelps, New York

REGNAD · Joined: 15 Oct 2006 Posts: 169 Location: RICHMOND VA

can that stuff be had at local stores? home depot or drug store or something? also, how do you tell if it needs to be replaced with out taking it out? or can you?

REGNAD · Joined: 15 Oct 2006 Posts: 169 Location: RICHMOND VA

so i have my new c-elements on their way, thx Curt, since the tubes are the same size between the g70 and 1252 that i have now. and the bolt pattern is even the same to mount to ceiling, is it safe to say that the same amount of tube will be used to project on the same screen?? does that make sense? Razz

**ecrabb** · Posted: Tue Mar 15, 2011 8:32 pm Post subject:

Mmm... I didn't think the G70 and 12xx had the same mount pattern... Could be wrong I guess, but I'm pretty sure the 12xx was two bolts and the G70 is three, and even the back two are spaced differently...

I moved the G70 back from my 12xx mounting location a little because the throw on the G70 is slightly longer and I didn't want quite such an aggressive raster usage. From all the reading I did, if you get too aggressive with the raster usage maximization (short throw), the G70 gets tough to converge and get decent focus in the corners.

SC

REGNAD · Joined: 15 Oct 2006 Posts: 169 Location: RICHMOND VA

i rechecked and it looks like the same exact hole pattern. ecrabb, what throw distance would you recommend for my 107" screen? i dont want to sacrifice clarity for tube use. does reducing the tube surface use reduce max resolvable resolution?

AFryia · Joined: 09 Mar 2006 Posts: 740 Location: S.E. Michigan

107 wide or 107 diag.?

If you want to be conservative on raster size use the PJCalc values or the tables in the manual for throw distance. Or say 95% of that value.

I don't know about resolution but reduced raster size will make setting up geometry easier.

CIR Engineering · Posted: Sat Mar 19, 2011 6:13 pm Post subject:

Just my $0.02, I wouldn't bother getting any glycol unless you find that you need it. G70's almost never have degraded glycol so you have a very good chance of finding that it is perfect when you remove the CElements. Look into the blue tube with the lens off. Does the glycol look clear, or does it have any yellowish tint at all. If it has any yellow at all than replace the glycol in all three tubes.

*the reason I say look into the blue tube is because the blue has a clear CElement and you can detect the yellowing with the CElement in place. Just because blue might be clear does not necessarily mean that red and green will also be ok, but it is a good indicator.

If you are careful you won't need to to add any glycol after you change the CElement; the bladders on the G70's are very large. Most likely you will trap some extra air when you install the new CElements, so be sure to bleed all the air out through the fill hole after you replace the elements. Just remove the fill screw and then push on the rubber bellows until a drop of glycol comes out the fill hole. Hold the bellow in that position and put the screw back in. Clean everything up with water and denatured alcohol when finished.

If you do need glycol you can get it from MCM.

http://www.mcmelectronics.com/product/20-4275

If you want to replace all three tubes with new glycol, I think the G70 will take about four bottles.

craigr

CIR Engineering · Posted: Sat Mar 19, 2011 6:27 pm Post subject:

REGNAD · Joined: 15 Oct 2006 Posts: 169 Location: RICHMOND VA

i havnt mounted the pj yet, but im liking the idea of standing it on its ass. i really dont want to remove the lens. what can i clean the replacement elements with before installing them?

edit, i just finished installing the two elements. i set the pj on its ass and leveled each tube as i went. ZERO spilage, glycol nice and clear. i used a soft t-shirt and ho6 breaths to clean the elements before lowering into glycol. final "approach" seating the element from one side to the other "pinching"the air out as i went.

draganm · Joined: 08 Mar 2006 Posts: 5080 Location: Colorado

CIR Engineering · Posted: Sun Mar 20, 2011 1:34 pm Post subject:

**ecrabb** · Posted: Sun Mar 20, 2011 1:42 pm Post subject:

Anybody can take out four screws to take off a lens... I bet he just meant to write that he didn't want to remove the tube, Craig.

SC

CIR Engineering · Posted: Sun Mar 20, 2011 1:47 pm Post subject:

Spanky Ham · Joined: 22 Mar 2006 Posts: 3910 Location: Comedy Central

What Craig said. The c-element removal is easy.

REGNAD · Joined: 15 Oct 2006 Posts: 169 Location: RICHMOND VA

yeah, i meant to say the tube. i have replaced the elements, didnt even push any glycol up onto the sealing surface of the rubber membrane dohicky< Razz

i have it sitting on table now, no seapage, figuring out my throw distance and what im going to have to do to remove 1252, patch things, and install new pj. ill be looking for some designer white next week. id like to go slightly bigger than 107 but id be forced to push my magnapans wider and i cant be having that!

REGNAD · Joined: 15 Oct 2006 Posts: 169 Location: RICHMOND VA

ecrabb, whats your throw distance to tube face, on your 110" screen?

REGNAD · Joined: 15 Oct 2006 Posts: 169 Location: RICHMOND VA

so i measured my distance from tube face to screen on my 1252 and its at 127" this is where i set it to make use of the most phosphor. comparing manuals of the 1252 and g70 i see that the g70 has roughly 3" shorter throw distance. tubes being the same size, if i have the g70 3" closer at 124" i should be using the same amount of tube face as in the 1252. do you guys agree? Ecrabb mentioned not maxing out the face for better edge focus, im not shure which way to go with this.