CurtPalme.com Home Theater Forum

[JustGreg]

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If this has been asked before I sure as hell couldn't find the thread.

I have gack in the red lens on my 11 year old 52" Hitachi. I religiously pull it apart every year and clean everything well; including the boards and all connectors and it's still going strong. Scan lines you could crawl though... but rock solid performance.

I tore it apart to clean it today but had to pull the red tube because of aforementioned mung. (The other two tubes appear fine.) I cleaned the chamber but now need glycol. The chamber 'lens' is an inverted dome so just removing it and pouring it in is out. It can only be filled through the port on the bench.

Looking at the tube I can see a flush blue dot ~1/4" on one side and assume it's the fill port. Being perfectly flush with the housing there's nothing to grab onto to pull it out. I'm guessing the removal process is to just push it out from the inside.

Question: I'm thinking of calling repair shops to see if I can bring it in and have them fill it. Has anybody had any success with this?...or for you repair techs, would you do it for a customer? Sounds like easy money to me.

Any thoughts on my question or advice for a good supplier of a small quantity of glycol? I don't need a gallon of the stuff as the TV is SD and has reached EOL IMO. (I say IMO because the wife doesn't seem to think so) I just want to keep it going a bit longer.

Thanks in advance.

[macgyver655]

Greg. I have cleaned and refilled many of RPTV tubes. Different methods depending on the tube style. It sounds like yours has a C element and if so then I usually remove the C element and drain it into a measuring cup. It is then possible to clean the chamber better and get all the gunk out. I would then measure out an equal amount of fresh coolant and pour it in and then reinstall the C element. Of course if some coolant had already leaked out then you wont get an accurate measurement. I just check the level when I first remove the tube.

MCM has coolant by the quart and maybe even less and I'm sure there are many others that have small quantities.

[JustGreg]

Thanks for the reply Mac. I went to a local (overpriced) electronics supplier and got a pint....a PINT, of clear for ~$17.00 with tax.

The LC chambers in the set have a nice convenient panhead screw with O ring to fill through. All I had to do was pull the tube assembly and refill it on the bench.

One thing I WILL do if I ever do this again is to put a little new glycol in and look into the chamber before just going full bore with the filling. I was a bit worried when I filled it right up, put the screw back in, and looked into it. It looked like they weren't mixing well at all. I was bumming. I just kept rotating the entire assembly until the air bubbles mixed it clear. PHEW! Wait...air bubbles?

I don't have an LC pj so this was new to me but I've read enough to know I needed to leave some space for expansion. However the problem with doing that is that you end up with a visible bubble around the perimeter of the inverted conical chamber glass that would have been visible as blooming. The way Hitachi addressed that was to build in a rubber 'golf ball' in the corner of the chamber. When filling the chamber I found I needed to keep my thumb pressed into the ball, or bladder a little bit, then fill the chamber, and reinstall the screw while still holding the indent in the ball. Then when you release the ball it stays indented.

So all done...boards are cleaned of glycol, mirrors are clean and the pq looks damn good for it's age. While it was apart I pulled the lenses and although there's the expected burn-in, the thing is just amazing... seeing as the life expectancy of a RPTV (before requiring higher level board replacements/repairs) is 19 months.

When the Wife's happy...I'm happy. (I can retreat to the dungeon and be left alone.)

[AnalogRocks]

[AnalogRocks]