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Dell Trinitron 17" flaky - worth repairing?

Discussion in 'Electronic Repair' started by Van Chocstraw, Sep 15, 2005.

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  1. I've got a Dell Ultrascan 1000HS Model D1025TM that was manufactured in
    May of 1998. It's quite similar to the Sony CPD-200GS (17" Trinitron
    tube) without the audio. I'm the original owner and have had no
    problems with it for 7 years until last week. The picture was fine, no
    shaking, no blurriness, warm-up time around 20 sec., no dimness, no
    strange sounds, nothing. It was perfectly fine.

    All of a sudden last week I turned it on one day and after about 10
    minutes the screen went black. There was no change in the picture
    before this happened. At the same time the picture went black the green
    light on the power button also went out. It didn't change to amber, or
    start blinking. I did hear a relay click out, as is normal when you
    shut it off.

    About 3 or 4 seconds after going black, it seemed to go into its initial
    power-on startup sequence again. The degaussing relay kicked in, I
    heard the static hum, then the other realy clicked, the green light on
    the power button came on, the degaussing relay dropped out and it seemed
    to be warming up again. But instead of completing the startup sequence,
    after about 5 seconds the green light went out again and I heard the
    relay click out again. This cycle then repeats itself over and over.
    At power-on, 3 relay clicks and the light comes on, then after a few
    seconds the green light goes out simultaneously with a relay click.
    Lather, rinse, repeat.

    If left off for an hour or so it will power on normally and display its
    usual crisp, clear picture. There are absolutely no defects in the
    picture. Brightness, contrast, changing screen resolutions on the PC
    (800x600, 1024x768, 640x480) all work normally and the picture is fine.
    But after it warms up, *click* and the light goes out and the
    startup-shutdown cycle starts again.

    I unplugged the video cable from the PC to see how the power-on
    self-test would go and it came up normally with the "No Video Signal"
    message and the color bars, so that test passed.

    I'm trying to decide what to do. In a past life I've done a little
    soldering on a TV set or two (15 years ago) and I have the service
    manual for it. Does the problem sound familiar to anybody? If it was
    something like a cold solder joint I could probably remove the boards
    safely and inspect them. Or, I could take it to a repair shop where I'm
    guessing a repair might run around $100 or so. Or I could order a
    refurb unit (same model) from a place I found online for $100 shipped
    with a 90-day warranty. Or I could buy a closeout (but still new)
    Viewsonic PF77 for $125 shipped.

    I'm not ready to make the leap into an LCD panel yet. Good ones are
    still relatively expensive, and there's no such thing as an all-purpose
    LCD panel. The LCD that does everything I need it to do hasn't been
    built yet for under $600.

    I know in my head the new Viewsonic is probably the way to go, but in my
    heart I hate to throw the Ultrascan out, especially since it appears, at
    least to me, like the problem might be very easy to fix. As I said, the
    picture is still bright, clear, and rock solid when it's on. I would
    appreciate any advice or tips from those who know more about these
    things than I do. I can't keep staring at this _really_ old and blurry
    MultiSync 3D for much longer. My eyes are bad enough.

    Thanks in advance,
    VCS
     
  2. Dave D

    Dave D Guest

    There are some *lethal* areas inside a monitor, especially the mains side
    reservoir capacitor, and some *painful* areas, like the CRT anode and focus
    supplies, which may result in severe involuntary muscle contractions causing
    serious injury or further electroction.

    If you are competent to go inside with the power on-

    Arm yourself with a can of freeze spray and a hair dryer/heat gun with a
    small nozzle. From cold, power up the monitor and see if carefully heating
    any section of the circuitry narrows the fault down. When it shuts down, try
    cooling each component in the area and try powering back on until you find a
    thermally defective semiconductor or capacitor.

    Failing that, personally I wouldn't recommend spending money on repairing a
    7 year old 17" monitor, it just isn't worth it IMO.

    Dave
     
  3. I'm using exactly that monitor now. It's a great monitor.

    Given your symptoms, I'd first suspect a bad connection in the AC input or
    power supplies, or just a loose power cord. In my experience, these are
    very reliable monitors. The only problem I've seen among three of them was
    a dried up capacitor in the vertical output which resulted in only half a
    picture.

    Do follow the safety advice though!!!

    --- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
    Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
    +Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
    | Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

    Note: These links are hopefully temporary until we can sort out the excessive
    traffic on Repairfaq.org.

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name is included in the subject line. Or, you can
    contact me via the Feedback Form in the FAQs.
     
  4. Guest

    Ignore this poster. It's a troll.


     
  5. Thanks for both of your replies.

    I have a healthy respect for high voltage and current. I adhere to the
    hands-in-the-pockets rule until I'm sure all dangerous charges have been
    neutralized. I have one of those big-resistor-welded-to-a-screwdriver
    thingies that's been in my toolbox for ages.

    I'll try another power cord first. The one in there isn't loose but it
    couldn't hurt to try another one. I'll proceed from there. I would
    just hate to throw it out. I'll poke around a bit (carefully) for a
    while. It'll be a distraction from the mind-numbing array of choices
    I'm wrestling with as far as a replacement goes. I'll let you know how
    I make out. Thanks again.

    VCS
     
  6. Guest

    Ignore this poster. It's a troll.
     
  7. Do you realize that you are giving amateurish advice to the founder of
    this group? :)

    Tom
     
  8. Sam Goldwasser wrote:
    Sam, I see you are the author of the FAQ. You are to be commended for a
    fine bit of work. I managed to get the main board out safely and am
    starting to examine things more closely.

    I have a comment regarding the Sony service manual for the CPD-200GS.
    On page 2-2 it recommends shorting the anode and the anode cap to
    chassis ground or aquadag AFTER removing the anode cap! What's more
    there's a diagram that indicates one should NOT slide a screwdriver
    under the rubber cap.

    Sony's been making CRTs for a long time so it seems strange they would
    recommend a dangerous procedure like that. Any cracks or pinholes in
    the rubber and you could wind up getting quite a jolt.

    VCS
     
  9. Guest

    Ignore this poster. It's a troll.
     
  10. It does seem strange.

    Perhaps they were worried about scratching the CRT? The glass is relatively
    thin in that area.....

    --- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
    Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
    +Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
    | Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name is included in the subject line. Or, you can
    contact me via the Feedback Form in the FAQs.
     
  11. Sam Goldwasser wrote
    <snip
    Sam, I see you are the author of the FAQ. You are to be commended fo
    a
    fine bit of work. I managed to get the main board out safely and am
    starting to examine things more closely

    I have a comment regarding the Sony service manual for the CPD-200GS.
    On page 2-2 it recommends shorting the anode and the anode cap to
    chassis ground or aquadag AFTER removing the anode cap! What's more
    there's a diagram that indicates one should NOT slide a screwdriver
    under the rubber cap

    Sony's been making CRTs for a long time so it seems strange they woul

    recommend a dangerous procedure like that. Any cracks or pinholes in
    the rubber and you could wind up getting quite a jolt

    VC
     
  12. Guest

    Ignore this poster. It's a troll

    Van Chocstraw wrote
     
  13. It does seem strange.

    Perhaps they were worried about scratching the CRT? The glass is
    relatively
    thin in that area.....

    --- sam | Sci.Electronics.Repair FAQ Mirror:
    http://repairfaq.ece.drexel.edu/
    Repair | Main Table of Contents:
    http://repairfaq.ece.drexel.edu/REPAIR/
    +Lasers | Sam's Laser FAQ:
    http://repairfaq.ece.drexel.edu/sam/lasersam.htm
    | Mirror Sites:
    http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header
    above is
    ignored unless my full name is included in the subject line. Or, you
    can
    contact me via the Feedback Form in the FAQs.
     
  14. quietguy

    quietguy Guest

    That makes sense from a OHS perspective due to the risk of scratching the tube -
    BUT like (I presume) most other guys I always did just that carefully anyway. And
    I don't know of any techs that would grab the rubber with their hands - if there
    are any they are much braver souls than me.

    David
     
  15. Dave D

    Dave D Guest

    Perhaps it's a throwback to the old Trinitron tubes which IIRC had a special
    anode cap with concentric contacts. They had a special tool to slide under
    the rubber and release the 'catch', though it could be done with a little
    care and a screwdriver.

    Dave
     
  16. Could be a throwback, although this model has a standard clip. Both the
    Dell and the Sony manuals recommend the same thing. I used the
    screwdriver method with a resistor. No problems. The anode cap had a
    schmear of silicon-like grease underneath surrounding the contact
    receptacle.

    The biggest problem so far has been dirt. There are things in there
    that look like they have hair growing on them. Ugh. It cleans up nice
    though.
     
  17. Guest

    Ignore this poster. It's a troll.
     
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