CurtPalme.com Home Theater Forum

noos@xp37+ · Joined: 17 Jun 2008 Posts: 464 Location: Berlin/Munich

Hello,

I now have three Crts in my basement that are in the need of bleeding (no air bubbles). The first one is my Barco 701, which also was my first CRT. Mint tubes, but never in use because of the lack of bubbles. Lots of Sonys without this problems later, I now bought a Nec 6PG Xtra on a local flea market! No remotes and nothing else included, but working and heavy burns in the center of the tubes (it was run with one fifth of the tubefaces!). And a friend now gave me the six eyed monster from Sinatra days (check AVS), with no bubbles. (http://www.avsforum.com/avs-vb/showthread.php?t=810439)
I simply can not/ I fear to remove tubes, but I am sick of collecting and not using CRTs with no bubbles.

So my idea is to bleed the burnt NEC tube while they are in the Projector by using a Dremel:

http://www.dremeleurope.com/dremelocs-ch/product/2709/396/dremel%C2%AE-4000/dremel%C2%AE-4000

I would bore through an upper corner of the glycol chamber glass (for sure not the tube glass), so that a little glycol squirts out. Then I would turn the projector to the side, so that the hole is on the highest part of the chamber, and seal it with some silicone. It (the silicone) should not interfere with the active tube face. And the tubes are so burned, it would not be too bad if the glass would be damaged/breaks.

How are my chances? Some recommendations? I guess that success depends on the right driller with the correct speed.

Let me mention: I am serious, and this is no training for the first of May.

Best regards

Marc

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Certainly not. Dont even consider it.

**Curt Palme** · Posted: Fri Jul 22, 2011 12:39 pm Post subject:

I hvae a feeling that the air bubbles at the factory were so small that you couldn't see them on the tube face. Even newly rebuilt tubes from VDC have no bubbles that you can see. I think we here (or at avs) 'invented' the visible air bubble. Smile

Your technique in theory should work, but since you're already taking the tube out of the set, why not do it via the fill/drain hole? You're not really saving yourself any time by your method, and risk glycol leakage over time.

noos@xp37+ · Joined: 17 Jun 2008 Posts: 464 Location: Berlin/Munich

**Curt Palme** · Posted: Fri Jul 22, 2011 6:56 pm Post subject:

If you're going to drill through the front, I'm pretty sure you'll shatter the glass...

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Its a pretty near certainty the glass will break, it is under pressure from the back that can in some cases break the glass without being touched, and youd have to be plain mad to try it with a rooted tube in a possibly good projector, since a breakage will spill the stuff all through the power supply.

Why take such a stupid risk for such a simple task? On rooted tubes of all things!!

noos@xp37+ · Joined: 17 Jun 2008 Posts: 464 Location: Berlin/Munich

Aussie_Al · Posted: Sat Jul 23, 2011 10:06 am Post subject:

noos@xp37+ · Joined: 17 Jun 2008 Posts: 464 Location: Berlin/Munich

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

I've bled 4 CRT Tubes, all from my NEC XG, The green tube it came with cracked on me one evening when I stepped out, came back the PJ was off.. I turned it on and saw sparks from the green tube. I shut it off immediately.

Further investigation lead to the glycol and lack of air bubbles. Bleeding the tubes is something I recommend. I had almost half a syringe of Glycol by the time I got done with my 3 new tubes. The blue tube was under such pressure that the glycol shot me right in the eye, at a pretty good rate of speed!

I would just take the tubes out and bleed the glycol the way it should be. Taking a tube out of a CRT projector isn't that hard. If a first timer like me can do it, anyone here can do it. Patience is the key Wink

Hope your draining goes well Very Happy

!