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Trinitron monitor faults

Discussion in 'Electronic Repair' started by Peter Baran, Jun 2, 2004.

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  1. Peter Baran

    Peter Baran Guest

    I have an AppleVision 850AV monitor, which uses a 20" Sony Trinitron tube.
    It was made in late 1997. Over the last year it has developed a multitude of
    problems effectively making it unusable.

    1. Image has lost focus.

    2. Many resolutions and/or refresh rates (but not all) have developed a
    proportion problem. The image at the sides is very squashed whereas it is
    spread out at the centre. Some resolutions and/or refresh rates have ceased
    to work altogether, even if they are not out of range - screen goes blank
    and makes a weird noise.

    3. Most annoyingly - the whole picture ripples all the time. The pixels
    basically jitter, and the monitor emits a buzzing sound. This occured
    recently and very suddenly, on all resolutions.

    I have taken the screen apart and looked at the Analog board. I found a
    charred bit and resoldered a couple of burnt contacts. Put it all back
    together but no improvement. 1 should be an easy fix, but what about 2 and
    3? I have no idea where to begin.

    TIA.
     
  2. Jerry G.

    Jerry G. Guest

    1. Loss of focus is usually attributed to high voltage regulation and focus
    supply regulation faults. This can be from the HV multiplier to start with.

    2. This sounds like you have a combination of pin cushioning and vertical
    deflection problems. This is usually attributed to warn down capacitors in
    these areas, and also possibly other support components.


    3. Jitter can be from a stability problem. This can be from supply voltage
    regulation, or noise in the supply voltage. This is usually attributed to
    capacitors that may be wearing down, or other support components.

    Unless you can have the service manual, training, troubleshooting skills,
    and instrumentation, you will not be able to service this yourself. This
    monitor also has multiple problems.

    If this is an expensive model (No model number and manufacture name given.
    Many use the Trinitron tube.), I would suggest you find out who their
    authorized service centre is, and send them the monitor for an estimate, so
    you may be able to make an intelligent decision about servicing it.

    There are very serious safety issues when servicing monitors, and TV sets.
    There are some very high voltages employed, and the power supply used can be
    lethal. Strong safety precautions and procedures are in good order when
    working in these.

    --

    Jerry G.
    =====


    I have an AppleVision 850AV monitor, which uses a 20" Sony Trinitron tube.
    It was made in late 1997. Over the last year it has developed a multitude of
    problems effectively making it unusable.

    1. Image has lost focus.

    2. Many resolutions and/or refresh rates (but not all) have developed a
    proportion problem. The image at the sides is very squashed whereas it is
    spread out at the centre. Some resolutions and/or refresh rates have ceased
    to work altogether, even if they are not out of range - screen goes blank
    and makes a weird noise.

    3. Most annoyingly - the whole picture ripples all the time. The pixels
    basically jitter, and the monitor emits a buzzing sound. This occured
    recently and very suddenly, on all resolutions.

    I have taken the screen apart and looked at the Analog board. I found a
    charred bit and resoldered a couple of burnt contacts. Put it all back
    together but no improvement. 1 should be an easy fix, but what about 2 and
    3? I have no idea where to begin.

    TIA.
     
  3. I don't think you should even bothertrying a repair. It sounds exactly like
    my Apple 17" that I tossed last month. Trinitrons just never seem to repair
    right. Just get a new monitor on ebay. I bought 3 (yes, three) 17"
    Viewsonics for about $100 including shipping.

    I just looked and there's a 17" applevision 17AV, for $10, plus shipping. A
    bit smaller, but you won't need a monitor adapter nor have to buy an
    outboard sound system.

    Once you get something like that then keep your eyes open for a nice cheap
    19" monitor with speakers. Buy a monitor adapter anyway so you can use any
    monitor on your Mac.
     
  4. Peter Baran

    Peter Baran Guest

    How can I tell which capacitors are wearing down? They all look normal (no
    bulging or leaking), can I use something like a multimeter?

    Already swapped it out with a 17" Sony 200ES, for the time being; found it
    on a dustbin in good condition a while ago. It's hooked up to a G4 which has
    VGA video anyway.

    Peter
     
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