Home Theater sales, calibration, service, and discussion forum. Hundreds of free manuals & setup tips.

Sign up and receive the latest newsletters by email!     Join the Forum discussions!    
    Site Map  
Home Products
For Sale
Links Contact
CRT Primer
Troubleshooting Tips
Mounting Methods
Definitive CRT
Projector Setup Guide
Tube/Raster Setup
Tube Condition (Wear)
Projector Rankings
Video Processors
Ampro 1500/2000
Ampro 2300/2600
Ampro 3600/4600
Barco (Older Analog)
Barco 70x/Cine7  
Barco 500/800/801
Barco 808/Cine8
Barco 120x/Cine9
Dwin 500/700
Electrohome ECP 
Electrohome Marquee 
Panasonic 108x
Sony 10xx
Sony 125x/127x
Sony 1292
Sony D50
Sony G70
Sony G90
Zenith 841/851
Zenith 895/900
Zenith 1200

Defungusing Sony Tubes Using CLR


Back to Advanced Procedures Index



The following procedure was written by Curt Palme. 

I’ve found that the CLR method for defungusing Sony tubes works really well, and in most cases this will clear out all fungus and eliminates the need to remove the front safety glass. This method takes about 15 minutes per tube.

Here’s how to do it:

1) Remove the two small Philips screws on the top of the tube.

2) Take a small pin or jeweller's screwdriver and poke it into the holes that the screws fit into. Usually the glycol crystallizes to some degree and clogs the holes. Free them up.

3) Drain the glycol from the tube (you’ll need new glycol, available on the net or from me). I use compressed air shot into one hole, which forces the glycol out the other hole. Note that the glycol is toxic and does not evaporate. Do not allow pets to lick it up! I drain the glycol into a large rubber garbage can…

4) Once the glycol is drained, I use a syringe to insert CLR to about the way point in the tube. The CLR is corrosive, so again, be careful. Put the tube face down, and swish the CLR around the tube for about 5-10 minutes. All of the fungus spots will be dissolved.

5) Drain the CLR from the tube, refill with fresh glycol, leave a small air bubble at the top of the tube to allow for glycol expansion, and reinstall the Philips screws. Keep the air bubbles right at the top of the tube, out of the phosphor area as shown below. Too much air in the tube, and you’ll see reflections below the screen area as light bounces off the edge of the bubble. You’re done!

Possible theory: I am guessing that leaving a couple of CCs of CLR in the tube might prevent fungus buildup in the future, but I have not proven this. Do it at your own risk! 

Secondary method to the 'CLR' approach to removing fungus from a tube:

This was sent to me by a CRT forum member. He told me that the CLR method didn't quite remove all of the fungus in his tube, but the following did.

Disclaimer: I personally have not tried this method, but the procedure seems sound...

  • Remove two screws at top of front glass plate
  • Remove the glycol using syringe to push air into the chamber and force fluid out (I use an air compressor and hold the tube over a large garbage can to force the old glycol out, shooting glycol gets messy!)
  • Note that the "fungus" (crystals, whatever) are on the tube side of the chamber; appears to be a thermal reaction with the glycol die, making it stick to the phosphor-heated glass
  • Fill the coolant chamber with rubbing alcohol. shake it around and leave it in there for 15 minutes
  • Empty chamber, fill it with soapy water with oxygen-based bleach (Snowy or other brand). leave it there for an hour use a very thin wire put through the holes in the chamber to help remove the green grunge from the glass surface (something like a stiff 18 or 20 gauge solid core wire will work)
  • Fill/empty chamber maybe 3 times to get all the soap out
  • Fill the chamber with clear glycol, leave it in for a few minutes to get as much of the water out of the chamber
  • Empty chamber, refill it with new clean glycol.
  • Optional: Use clear glycol and add a bit of blue and yellow laserjet printer ink to match the color. after you've put it in the chamber, agitate chamber to make sure all the color is evened out.
  • Replace tube and re-converge (usually very minor)

Did you find this information useful? Please consider making a donation to help defray the cost of managing and hosting future articles, tips, and documents.     

Or purchase from and a small percentage automatically goes to support this site at no extra cost to you! Visit their Blu-ray and DVD stores for sales. Want to show off your home theater? See our Blu-ray Release List & Must-Have Titles. Shop at and support our site!


Copyright All Rights Reserved.