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Philips 109P4 Trinitron CRT

Discussion in 'Troubleshooting and Repair' started by Emir, Nov 15, 2016.

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  1. Emir

    Emir

    2
    0
    Nov 15, 2016
    Hi,

    My oldy 109P4 -which utilizes a sony trinitron tube- needs some maintenance. Last year, all of a sudden its RED color broke loose intesely, gone RED on the screen. Until then I've replaced it with an LCD, but decided that I don't want to waste a trinitron CRT.

    My guess is Green tube is fading away. Recently I've replaced BNC connectors with Anolog cables, but no chance.

    Trinitron CRT gives much more deep and sharp image quality, which in turn helps me getting really enjoyable view...

    If there's a way to recover it, I'd ready to try at least before I dump it to the waste.

    Thanks in advace
     

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    Last edited: Nov 15, 2016
  2. shrtrnd

    shrtrnd

    3,795
    503
    Jan 15, 2010
    It doesn't sound like you've got any experience troubleshooting electronic circuits. Do you know anyone around you who does?
    I can't see your problem, but this is basically what would need to be done:
    1) Only somebody familiar with CRT's should mess with them, because there's high voltage on the tube anode
    even when the power is off. It's stored like in a capacitor.
    2) In the old days a lot of repair shops had 'picture tube rejuvenators', to try to solve your weak green gun.
    3) It may be in the neck of the tube, but you probably have damage on the color/convergence board itself that is
    causing your excessive red.

    Somebody familiar with old CRT displays would know what to look for. Nobody here will recommend that you
    try to fix this by yourself with little to no experience, because of the dangerous high voltage involved.
    If you don't know anyone around you who has experience with this type of display, you really should just
    trash it. And if the CRT tube itself did go bad, NOBODY can fix it anyway.
     
  3. Emir

    Emir

    2
    0
    Nov 15, 2016
    Correct that I've no experience on CRT, and I assure you I've no intention to mess with it myself.
    The problem is however, the maintenance guys I spoke to don't want to mess with it either.
    It's because they don't have enough experience or maybe too costly might it to be rebuilt, I really don't know.
    My intention is maybe there's way to point that maintenance guys into some path to ease their effort.
    Otherwise, it's so easy dump this once-brillant device into trash then..
     
  4. shrtrnd

    shrtrnd

    3,795
    503
    Jan 15, 2010
    You need somebody old enough to have worked on CRT displays. New techs don't know anything about them.
    If you're going to trash it, believing it unsalvageable and not worried about damage you might cause, I'd open it up and take a look inside the housing before throwing it away.
    If I remember right, the Trinitrons are front-heavy. All the weight is in the front of the CRT, and the back cover is
    very light by itself. If you take the back housing off the display, lay the set face-down, on the front of the CRT, and
    remove the housing screws so you can take the back cover off. If you try this with the set standing up normally, when you remove the last screw from the back of the housing, the CRT heavy assembly will fall forward, and maybe
    off of whatever work-surface you're using.
    If you take the back cover off, just look inside for excessive heat damage to components. I'd be paying particular attention to the color circuit. Sometimes a small board attached to the yoke around the neck of the CRT tube.
    sometimes on the board the yoke wires are attacked to elsewhere. I believe you'll find a component burned-up on
    that circuit that resulted in your excessive red on the screen.
    I'm just suggesting this as a last-ditch effort to save the display. Not knowing much about troubleshooting and repair,
    you might further damage something in this process, and I disclaim any responsibility for that.
    If you find burned components, maybe then 'the maintenance guys' there, can identify the problem for you and help identify the bad component(s).
    You probably can't tell for certain if your green is weak because it's being washed-out by the excessive red. But even
    if you get the red circuit fixed, you may still have weak green.
    Trinitrons are nice displays, but they were always expensive to fix. My suggestion here is, like I said, just a last-ditch
    check to see if your problem is a simple one or not, before trashing the display.
    The high voltage on the CRT is at the larger diameter wire/plug that is attached directly to the back of the large CRT tube. Stay away from that.
    I hope it's needless to say that the power cord needs to be unplugged, before you attempt any of this.
    Just a thought, in case you want to look at what you have before throwing the Trinitron away, and I wouldn't blame you
    if you just disregard what I said here, and trashed it without trying to disassemble it.
    Stay safe and good luck.
     
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