Last CRT I buy this year I promise!!!! - RASTER EVENING

So after deciding that I wanted to upgrade from my Seleco 350+, but having no money to do so, I got hold of a barco 701s (credit card company is going to love me!)

For my money I managed to pick up:
1x Barco 701s with no blue
1x Barco 701s not working, no lid, no lenses with 3 tubes
1x Barco remote
3x Sony SD187 tubes in mint condition

So I've set it up and all in all am very impressed with the Barco over my Seleco - digital convergence is nice and the toshiba tubes are noticeably brighter than the Sonys.

Problem is burn... The green and red look ok, about 6/10 green 7/10 red. The other 3 are a bit less burnt, but the raster is not exactly nicely large and in the middle!

So... using a mac and a free paint program, here is an attempt to spread the burn so that I can use a larger raster... results to follow.

[cosaw]

I'll follow this closely as would be interested to see how it goes - have seen at least one succesfully done over on the AVSforum some time ago.

What sorta brightness/contrast are you gonna run and for how long? Is it a set stationary image your displaying or is there any movement whatsoever? You doing one tube at a time I would think?

Would be interesting to know after how long wear starts to appear - quickly I would think. Can building up the wear/burn pattern quickly have any negative effects over the same result which would be achieved through doing this procedure more slowly?

Simon

Well it's been running for about 18 hours so far and barely made a dent!!! I've got the brightness up at 90. Considering the tube as if it had even wear of what I am putting on to it, I'd say wev'e gone from a 10/10 to a 9/10 - ie you can just about see where my new raster is.

The mask is completely static a the moment, but I intend to make a much softer edged replacement once I start getting close to the right burn.

Pictures as and when there's a noticeable change...

[cosaw]

18 hours!! Blimey - what do you do put it on standby every 30 mins and check the wear? Whats your contrast at? - perhaps that'll make it go quicker. Mind you turning contrast much higher than 70 on mine and the pj starts sizzling worryingly.

Si

[Roland @ B4]

Boy Lex as I pointed out off line that 701 does not have the complsory heat shut down circuit issued by Barco when a new tube is fitted.
This was done because the Toshiba tubes can overheat and fail (ie crack)especially if you get too close to the edges.
I would keep checking the temperature of that tube if it feels more than warm give the projector a rest. It would definitly worth putting a fan on it too with the lens off to help get some heat out of there.

I think you should start a book on how long it will take to get the wear the same across the tube. I will offer my guess at Two weeks i e 360 hrs. I tried it once and gave up. But I have seen some new projectors go in less than 24hrs.

Good luck I'll watch with interest. You have nothing to loose.
If you ever find out who installed that projector an a screen that far away name and shame them.

Well it came from MOD, so lets not eh?! Could have paratroopers storming the place!!!

Thanks for the advise re overheating... I'll put a fan on it now!

Cor blimey!!! Glad you posted that when you did! Just as I was putting the fan up to it, I decided to touch the front of the tube... OUCH!!! Hot is not the word! It's cooling off now. Super powerful fan on it now, so that should help when it goes back on. I also noticed that all of the LEDs had turned orange... presumably it should have shut down if it had the heat protection on it? It doesn't seem to have affected anything as it came back from standby with green lights and displayed the DVD on the other input fine. I'll put it back on in half an hour when it's cooled down.

If it's going to take 2 weeks then I'm doubly glad I decided to do it at work!!! He he!

[Roland @ B4]

Originally Posted by Boy Lex

I also noticed that all of the LEDs had turned orange...

I don't think that is possible. I suspect you have been looking at the blue light too long. Bit like a moth I guess.

Maybe!!!! I'm dreading driving home now... got these big blue lights in front of my eyes everywhere I go!!!!
Hopefully some photos in the morning with some change!

Something is happening!!!! Well very slowly anyway - I think Roland might be about right on how long this is going to take!!

Here is the tube after 46 hours - you can just about make out the new raster edge. The fan is doing a great job of cooling it though - it's barely warm to touch now.

Raster has become clearly visable (not so much in photo, but to the eye!)... Still a long way off tho.

That's a grubby finger mark at the top where I'm checking temperature!

Starting to match with the least worn areas of the old raster, so I've now modified the mask to burn the least worn bits to the level of the worst worn bits. Not expecting a miracle though - there's a tiny dot burn in the middle (where I guess the deflection must have failed at some point) and there's also the sky sports and mtv logos that I don't think there's anything I can do about.

[cosaw]

Looking good - how sophisticated is your mask - what software are you using to create it? How are you getting it to line up? Do you project your desktop with a tube and then mask out in a paintshop package? Got a pretty good idea of how I might do it just wondered if you had any tips.

Hi Si

Exactly as you describe - I'm using a freeware paint programme and painstakingly using a soft edged paint brush to create a fuzzy edge. Last night I left work and my boss turned it all off (including the mac) thinking that I'd left it on by accident, so I had to go in and create it all over again!!!

i basically put the lens back on with just the top two bolts and plugged the green in at the back and redid it. I'm just using white, then when the mask is ready I'm lowering the G2 on red and green and unplugging red and green, defocussing the blue G2 and then removing the lens and putting the fan up close.

I'll pop in again later today to check up on it.