1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Eek! Barco 701s problem

Discussion in 'Projectors, Screens & Video Processors' started by Boy Lex, Sep 16, 2005.

  1. Boy Lex

    Boy Lex
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Gutted - after all the hard work trying to sort the blue wear out, I finally got round to setting the 701s up at home last night.

    Through the line doubler it was looking excellent - did a convergence settled down and watched some tv on it. Was generally very chuffed that the old blue wear pattern was barely noticeable. I was just thinking about where to ceiling mount it and lent (not hard) on the top above the blue tube. I heard a spark and the blue tube went way bright, sucking all the light out of the other tubes and unsurprisingly the pj shut off. It now does this everytime it turns on.

    I've tried swapping the blue and green sockets and this moved the problem to the green tube, so I'd guess the tubes are ok? Any ideas on what to try - I've got some spare boards I can swap.
     
  2. cosaw

    cosaw
    Active Member

    Joined:
    Jun 14, 2003
    Messages:
    753
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    31
    Location:
    Stockport, Manchester
    Ratings:
    +19
    Hi Lex,

    Sorry to hear that - you'd done such a good job as well. So you leant on the lid when it was down and it went at that exact point? From what you've said it doesn't sound like the tubes but perhaps you've cracked a board or snaged a wire - guess you've done all the obvious stuff like re-seating everything and checking connections. The 701 has alot of the boards layed flat on the top of the tubes doesn't it on some sort of hinged mechanism with the lid then going down above that. Is it a possibility that this mechanism wasn't returned to its seated position fully and then when you put the lid down it fouled on it and then put more pressure when you leant on the lid?

    Not sure where you'd start in diagnosis but fyi there are a few Barco 70* bits going on ebay at the mo - in your search just type "Barco" - you won't find them under CRT. But don't suppose that's any good till you get an idea of where the fault may lie. I'm sure someone will pipe up with some more helpful suggestions shortly.

    Hope you get it sorted.

    Simon
     
  3. Boy Lex

    Boy Lex
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Thanks for the tips Simon.

    I'm a bit lost without the internet at home and with avforums being down quite a lot on friday - I managed to sort this out on thursday night and I tried to post, but it didn't happen... Broadband arrives on Wednesday which will be nice!!

    So anyway - I decided that the problem may lie in the socket, so I took a socket from a spare tube that I took with it (man am I thankful I took the spare chassis and all the spare boards he had kicking about!). Swapped it and bingo - it's working again - b.e.a.utiful!

    Very chuffed cos for the first time it's been the first thing I've tried!

    Anyway - I'm a little concerned that it may have been some HV leaking somewhere that caused it... Every hour or so, I hear what is either the creak of the chassis getting warmer or a little hv arc - I can't decide which. Any ideas what to check to make sure this isn't happening?

    Also anyone know what might have gone in the socket - it would be nice to have a working spare again?
     
  4. cosaw

    cosaw
    Active Member

    Joined:
    Jun 14, 2003
    Messages:
    753
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    31
    Location:
    Stockport, Manchester
    Ratings:
    +19
    Glad you got it sorted :)

    Broadband is certainly the way to go now its becoming more affordable had mine around 3 months now - its great mostly.

    Spares really are a great help to have as a backup and for fault finding especially if you're less electronically capable at a lower hardware level like myself but I'm learning electronics slowly.

    The noises could just be the case warming - I get plenty of cracks at warmup and think is that the chassi or something else? Maybe a good way to check for arcing is with the lid off in a dark room running video but with the lens caps on so you're not projecting to screen. You might see some sparks that way and if you cease to get noises you'll know its probably the lid warming. Careful in the dark with the lid off though!!

    Si
     
  5. Boy Lex

    Boy Lex
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Yeah I've done that - it's a bit too irregular for me to sit and watch though! Maybe it's fine and the blue socket was a random component death.
     
  6. Boy Lex

    Boy Lex
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Found it!!! Bit of an odd one because I can't figure out where it's coming from, but there is some arcing from the first ring on the blue tube (closest to the socket before the yoking) and the metal clamp which holds the ground heatsink part of the socket on to the tube. I noticed it spark a little when I turned it on after it had been idle for a day. I guess this could have thrown out the IC on the other socket - so unless I figure out how it's happening I stand to lose this good socket too.

    Any ideas?!
     
  7. cosaw

    cosaw
    Active Member

    Joined:
    Jun 14, 2003
    Messages:
    753
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    31
    Location:
    Stockport, Manchester
    Ratings:
    +19
    Good work on the find. Well if I were doing it having a limited knowledge of electronics I'd use my mechanical over electronic skills - strip the whole thing down look it over for burn signs - clean it up - look it over again. Hopefully you'll find something - if not reassemble and see if it still has the fault. A rather primitive approach perhaps but as I say that's what I'd do with my limited knowledge on elctronics and tube construction. It's probably easier said than done as you'd probably need to recalibrate bits a pieces when you rebuilt the tube - Curt's site has at least some stuff on this:

    http://www.curtpalme.com/CRTReplacement.htm

    I know your not replacing but I'm sure some of this info could be useful.
     
  8. Boy Lex

    Boy Lex
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    That sounds like a good idea - I'll try and get to it on the weekend.
     
  9. Boy Lex

    Boy Lex
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Ok. I e-mailed Curt who was kind enough to give me some advise. He's fairly sure there's a short in the tube somewhere and has suggested removing the HV lead to test it. Bit of a bummer... wonder if the week or so of running it high might have caused it.

    Well it looks like I might be on to plan b, which is to fit these lovely clean sd-187s to it using some sockets from a barco 700. Sacreifice in brightness, but no burn whatsoever.

    I'm on the scrounge then - anyone got three Barco 700 sockets?!!!
     
  10. cosaw

    cosaw
    Active Member

    Joined:
    Jun 14, 2003
    Messages:
    753
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    31
    Location:
    Stockport, Manchester
    Ratings:
    +19
    Nice to get such a speedy reply from Curt - he's a busy man no doubt. You may find a spare blue kicking about on ebay at some point.

    I've got the SD-187 tubes in my pj. Its my first pj and so far I've been happy with the brightness running at about 6.5ft wide on my homemade screen which will go to 7ft. Not had anything else to compare it with but the tubes have had very little use so the output should be good. I couldn't notice less brightness at 7ft but the ceiling won't allow more than the throw for 6.5 which is about 10ft away with my lenses.

    Well only you will be able to know if you notice a difference in the tubes but I'd be interested to know the result.

    Si
     

Share This Page

Loading...