11
Nanos
18d

Modern technology is so reliable..

I used to have a 30 year old CRT colour monitor, tube eventually wore out..

Got a brand new LED monitor, less than 3 years old, picture goes..

At least these days there is YouTube to try and fix your own TV..

Comments
  • 4
    Be careful. Some old LCDs have some sort of fluorescent tube in them. The driving circuit jumps the voltage from 20VDC to 1000V when powered. However, that is a hell of a lot safer than tube based monitors that could have 50K volts in the picture tube even when not powered. How old is your LCD? Not sure what they have in the new ones.
  • 1
    @Demolishun he already said it's LED backlit
  • 2
    @Demolishun

    I do rather worry about how you are supposed to handle high voltage stuff, as such I tend to simply avoid it all together !

    I have a vague memory of hearing something about discharging things before you work on them, but googling never really got me any answers on how to do that.

    There must be something on YouTube by now right ?
  • 2
    So far a bit of googling suggests it might be a broken capacitor or several needing replacing. (I've done that before, but only on PC equipment.)

    Or maybe the LED lights inside.

    Symptoms are, it turns on fine, works for a few minutes and then the picture goes totally off, but sound is still on.

    Turn off and on again, same thing, different random time.

    Sound capacitor issue like ?
  • 1
    @Nanos Jub. Sounds like. You can have a look inside, and if there are some caps blown, discharge and replace them. Otherwise you can usually just replace entire modules...
  • 3
    Fixed a Dell U3011 using a £2 part because of a forum post. Best display I’ve owned.
  • 0
    @Demolishun 50kV looks a bit too much for me...
  • 1
    @StefanH

    I'm reminded of a blown part in a computer once I had, the replacement was $100,000 USD !

    As that was a tad beyond my ability to afford, it was time to sell it on..
  • 0
    @Nanos did you own an IBM mainframe?!
  • 1
    @StefanH

    HP Supercomputer. :-)
  • 0
    Looks like LED arrays go up to 35VDC. A lot safer than older models. Just gotta watch out for 120/220 line voltage then. Just unplug then. Nice.
  • 0
    Planned Obsolescence. Nothing more.
  • 0
    @Demolishun Caps in the smps can still be charged after a day. Dont open stuff unless you know what you are doing.
  • 1
    @NoToJavaScript It is not planned, they just make it work and dont care about the longevity because the product would be more expensive.
  • 1
    @Gregozor2121

    How do you get to know what you are doing ?

    Without it taking like a decade of your life in the process !

    Otherwise it gets expensive throwing stuff away just because it doesn't work.

    Not helped by living someplace that the nearest person who might know how to fix it lives 500+ miles away..
  • 1
    @Nanos
    You have to know basics to even start learning about the subject. Then it will take a bit of time to research and learn how stuff works (theory, math, practice) and only after that you can attempt to repair nearly everything on a decent level.

    If you want, you can try to repair everything even if you have little knowlege but it increases the failure and death propability. Those warnings are there for something.
    Not everybody will be able to learn how everything works this is why you have specialists that can do it for you for money. I traded a lot of free time to learn how everything works.
    The most important thing is to have common sense but even with that you can get killed because you wont be aware of something.

    The more effort you put into learning the better the propability of success.
    There isnt a way to do it quickly. Just stick with people who are willing to teach you, that will help you learn faster. But experience is equaly as important.

    I can help you learn.
  • 2
    @Nanos I went to a tech school for electrical/electronics engineering. That is one way. First learn about electrical safety.
  • 1
    @Demolishun
    I have meet people from technical high schools who would die 1000 already if not for their luck or propely idiotproofed instruments.

    Learning about circuits can get you so far... You have to learn from the other side as well, look how real things work and which things do what without getting into theory.
  • 1
    @Gregozor2121 Its all about V/R = I. Too much I in the wrong places and you die. Also AC kills because of fibrillation of heart. So 50V can kill. Electrical safety covers this.
  • 2
    @Demolishun
    But wait there is more!
    AC is more dangerous because it can go through capacitance. So even insulators wont be able to help you.
    AC is more dangerous because it creates more current because (reason above), both DC and AC are bad because they fuck up the heart and mess with other muscles.
    Some HV are safe because of their high impedance but you have to know what you are dealing with. Caps can store HV for even a day after disconnecting, safety depends on their capacitance but in general dont touch anything above 50V.

    That is most of it yes but then you have to know how to spot danger. Huge eletrolitics, HV CRT circuit, where the mains are on the PCB and what can happen in the fault condition. (On example how to connect a metal lamp so your ground fault interruptor actualy trips when it breaks). Those require more than simple training, thise require theory and practical knowlege about circuit and dangerous components.
  • 1
    @Gregozor2121

    > Caps can store HV for even a day

    > after disconnecting

    How about leaving like a LED TV turned off for a week before fiddling ?

    I'm aware how dangerous these things are, since my dad (Who isn't around anymore..) worked in the television field told me about a college at work who got a shock, went outside to get some fresh air and dropped dead.

    This is why I usually try and avoid such things.

    I'll make a note on my todo list though, learn slowly about electrics/electronics, so that one day, I will know what to do.

    Previous experience of fixing a CRT TV many years ago was to open the back, poke it with a long wooden stick and see where the sparks came from..

    Then turn it off by pulling the plug out, leave it off for a week, before soldering a replacement part from an identical thrown away TV.

    That worked, and didn't kill me obviously.

    So, how safe was it using a long wooden stick ?

    (At the time, there was no one else to ask !)
  • 1
    @Gregozor2121

    Hopefully if I get to move at some point, I might be near enough to find someplace or people to learn from in person.

    Here, hardly one knows anything that I've met so far. :-(

    It is one of the great tragedies of modern times, with skilled folk leaving the countryside and moving to the towns, means there is no one left to fix anything !

    As such, everything begins to fall into a state of disrepair like some post apocalyptic world filled with rusting vehicles and roofless houses..
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