What happened here ?


Active Member
Barco Data 701.

I had just finished filling blue tube with fresh coolant. It had suffered a major leak and was unuseable. The glass was removed from the crt and cleaned. The silicon was left for two weeks before refilling the tube. The projector was put back together and everything appeared to be working fine. The projector had been running for around 20 minutes with no problems when suddenly pop! followed by shutdown.

This is a real pity as the green and red tubes are like new and the chassis has done less than 2000 hours.

Would anyone like to speculate as to what went wrong ?

Have I slipped up somewhere along the line ?

Is the failure just a coincidence ?

The cracks appear to be behind the glass face looking like they are in the coolant itself.


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Oh dear - I'm sorry about your loss.

In your photo the tube appears to be still filled with coolant. I'm referring to the small elongated bubble at the top of the tube face.

Still, the phosphor looks severely damaged and even the front glass seems to be cracked. Maybe your coolant fluid boiled. What kind of fluid did you use for the refill ? I think the original kind is some kind of glycol (like car radiator fluid, only cleaner)


Active Member
In your photo the tube appears to be still filled with coolant. I'm referring to the small elongated bubble at the top of the tube face.

You are correct, the tube is still full of coolant. The bubble at the top is there specifically to stop expansion of the fluid cracking the glass when the tube warms up.

The Coolant came from a well respected Barco source so I doubt if the coolant itself is to blame. It looks to me like a huge lump of phosphor has been zapped off the back of the tube. Catastrophic scan failure ?


This is just a thought, but if the projector was run at all without coolant before you refilled it, I wonder if that would have damaged the phosphor. At which point filling it with coolant, just prolonged the total damage somewhat.

I don't know if phosphor behaves that way, but if the coolant was the right type, I'm not sure what else would explain that.



Standard Member
sounds to me like you over filled it , the coolant expanded and the tube was the weaker structure and smash :( sorry to hear that tho.


Active Member
Thanks for the thoughts guys.

This could be a lesson for others trying to refill tubes. I left a much larger air gap than suggested in the eboyztoyz guide yet it would appear not to have been enough. If I were doing this again I would leave a much bigger air bubble.

Hindsight is a wonderful thing !


Boy Lex

Can't really tell from the photo, but can you tell if it's the outer glass that's cracked or the tube glass. If it's the outer glass, you could start over and get a glazer to make a replacement for you.


Active Member
Boy Lex,

Looks like the inner glass is cracked as the outer feels smooth. Either way the phosphor is so badly damaged the tube is unrecoverable. The strange thing is that the cracks look like they are in the coolant itself. Also strange is the fact that none of the coolant has leaked out.


Active Member
hi will one of the remotes work with a 708 if so let me know how much mate cheers :thumbsup:

Kev the Gerbil

Standard Member
Looks like the tube have gone seen a lot in tv & monitors which go the same way only from behind the crt when been dropped or on a high voltage flashover the only way you are going to get it working again is take it to a repair centre or a good tv repairer just in case there are no faulty components on the pcb the works the blue tube

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