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Ok! Blow by blow of defung!

Discussion in 'Projectors, Screens & Video Processors' started by Boy Lex, Jan 10, 2005.

  1. Boy Lex

    Boy Lex
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    :)
    Ok then. After request, here is a blow by blow account of my defungussing experience on my Seleco SVP350+. I picked this up (paid a bit too much I think :mad: ) and it had 6500 hours on it. Blue and Red were fine, but Green seemed very difficult to focus and any picture on it had green halos around anything vaguely white. :confused: Looking directly at the tube I noticed a load of speckling - particularly around the top scan line... In fact the picture was fine at the bottom and got progressively worse towards the top (bear in mind I'm desktop front and I think this came from ceiling front).

    After a bit of research I discovered that the 'fungus' is a deposition on the tube, the result of the glycol coolant in front of the tube reacting with the aluminium housing (more on that later!)

    I used the guide at eboyztoyz to 'defung' the tube: http://www.eboyztoyz.com/index.php?ncat=145#Fungus_removal

    I must apologise for no pics - my digital camera was not to hand, but the pics on eboyztoyz are helpful and more or less exactly what I was doing.

    First off I pulled the tube out carefully to the end of the projector (this way I didn't need to disconnect anything except the tube board). I removed the screws from the tube face to try and drain the coolant --- nothing came out!! I was baffled that my physics wasn't working - one hole for air in the other for water out? Anyway I left a jamjar underneath the holes while I used the blade from a stanley knife to cut through the sealant at the top. I tried using the knife assembled, but it was really difficult to get it to go straight into the sealant. After I pierced the sealant, the coolant started to come out much more quickly, and I left it to drain (took about 15 mins).

    After I'd captured the coolant in the jam jar I cut through the rest of the sealant (boy it's tough!! - had tasty wrist ache afterwards!). When I got the glass of I was gobsmacked by just how much of this fungus there was on the tube - it resembled the grease in the bottom of a frying pan after you've made a batch of bacon sarnies! :p

    I carefully used the blade to scrape the fungus off the tube - which came off as a greeny sludge - nice! :smashin:

    Removing all the traces of sealant was a bit of a task and took a while, I think I may have made a gaff here. :oops: In scraping the sealant off the tube housing, I removed a fair bit of paint from the housing leaving bare aluminium. It wasn't till after I'd resealed it that I discovered that it's aluminium that causes the chemical reaction - so I may have to do it again sooner than another 6500 hours and repaint the tube housing this time! :nono:

    Anyway - I got all the sealant off the glass and the housing and I was keen to avoid any floaties (little black bits of sealant inside the coolant chamber) so I got out the vacuum cleaner and sucked what I could out of the chamber. This was pretty effective as I noticed little black bits coming out of different nooks and crannies. Rather than potentially scratch the tube surface I held my thumb on the side of the hose and ran it across the tube a few millimeters off it.

    I then used a bit of window spray to clean all sides of the tube and glass.

    The sealent I used was just a multi-purpose sealer I found at B&Q in black. It was £7.49.

    It took me two attempts to get it perfect - the first one I just hadn't put a big enough bead on. I left it stood upright (propped up by a screwdriver) and left it 24 hours to dry. :boring:

    24 hours later - I'd filtered the coolant (light blue in colour). I'd been to the chemist and blagged a syringe for free (had to convice them I wasn't a junkie :blush: ). It did the job but it was tiny and really slow!!! I think if I could have been bothered to go to another chemist it would have taken much less that 2 hours to refill the chamber!!!

    Anyway - refilled it with all I had and was about a cm below the top. I'd been trying to find out what to top it up with and had found out that the glycol is exactly the same stuff as antifreeze - except that antifreeze is heavily tinted blue.

    I tried putting a bit of antifreeze in, but it seemed wildly different and started to sink - i think that the coolant is probably a mix of glycol and water. I ended up topping up the 1 cm with deionised water.

    Put the screws back in - put the tube back in stuck it all together again, switched it on and nasty smell of burnt out components from the deflector board!!! Argh!! :oops: Anyway that's another story altogether in a different thread!!

    Now that the deflector board is fixed I've had it running all weekend. There were a few air bubbles in the tube to start with, but they disappeared almost as soon as the PJ was powered up (convection currents I'm sure). I also noticed one floatie!!! Doh!!! Anyway it seems to be quite happy outside of the raster area (I'm sure convection currents again!). So I'm currently getting a good as new picture out of this green tube! :) It will be interesting to see how quickly the fungus returns with this exposed aluminium in the chamber tho.

    Hopefully some pics of the end result as well as my makeshift PJ stand coming at the bottom of this thread in a couple of days!
     
  2. Boy Lex

    Boy Lex
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    Here is a pic of the green tube prior to defungusing. You can see the algae sort of deposit around the bottom of the raster.
     

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  3. Boy Lex

    Boy Lex
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    Ok... long awaited I know, but here are some piccies for you... Sort of a before and after except I didn't have the digi cam available when I did the defung so I'd put the lenses back on and couldn't be bothered to take them off for a proper after pic. Anyway, knock yourselves out! :)

    Oh yeah. Also included is the home made stand that prevents screwing into the ceiling... Won't it be nice when I've got on that first rung of the property ladder and I can drill into my ceiling!
     

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  4. mintminty59

    mintminty59
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    I got that exact problem on a green tube on a 390 aswell :) sounds like I have to give it a go. I notice u also have the same problem I do with regards to the sides of the picture sloping in wards (nothing i do shifts it) and I like the idea of that stand. I basically used a old chest and I put it upright behind the sofa to. The seleco's give a nice pic. I got a 350 aswell and a 195. I cannot really tell much differance between the 195 and 350 but the 390 makes a slight differance. Thanks for the step by step guide. May I ask why did the deflection board burn up. Does this always happen when u remove the glass to clean as I have heard of it many times before.
     
  5. bxd

    bxd
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    Hi,

    Just a quick comment on mintminty59s, "keystone" problem..the projector isn't designed to be mounted as it's shown, so you are probably 'out of range' or at 'one extreme' of the keystone correction. If you want a picture that has parallel sides, then you should mount the projector flat on it's base.

    Brian
     
  6. Boy Lex

    Boy Lex
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    The piccies are a bit deceptive. The picture on the wall is perfectly straight, but I can't take a completely perpendicular picture without standing in front of the tubes!
    I've mounted it so that the tubes are perpendicular to the centre of the screen - the manual suggests you do this for rear projection and I figured why not for front too. I've adjusted spacers to the rear projection table.

    As for the deflection board, who knows? I can't think of anything that I might have done to cause it to blow the chip. I wouldn't expect it to happen again if I had to defung another tube. I'd certainly give it a go minty - I can't tell you the difference in picture, it's astounding.
     

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