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NEC Multisync 1550v Dead (so's my brain)

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    #1

    NEC Multisync 1550v Dead (so's my brain)

    I wasn't going to bother with this one, got it in a batch of 7 dead LCD monitors. I usually only do 17" and above, but this little NEC looked nice, and there's probably someone locally that has a dead monitor, and can't afford to replace it, that would "settle" for a 15.

    So I plug it in, dead. No power light - nada.

    I disassemble it, and it looks like a nice quality unit. I used to think NEC made great monitors, though had quite a few 17" CRT units fail in the mid-90s at a company I worked for.

    So anyway, I figure I've got reasonable troubleshooting skills. I'm no PlainBill, but I do ok.
    The main fuse is obvious, a glass fuse right near the power connector. I test it, .2ohms. OK, I'm surprised but move on. Apply power and measure the big cap. Nothing. 0vdc. Ok, maybe the bridge rectifier failed open.

    So I'm about to remove the power supply from the bracket, unplugging connectors, and there's this 2 pin connector with fairly large wires on it.
    I think, oh that's the ac power input. Wait... no the power connector is on the board. These wires go to.... the master power switch. D'oh!!!!
    <slaps forehead>

    So I turn the master switch ON, and push the power button.
    Monitor comes up, seems to work just fine! Looks like someone recycled it just 'cause it's small.
    36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....
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    #2
    Re: NEC Multisync 1550v Dead (so's my brain)

    Been there, done that. No power... No standby... fuse ok... it is plugged in... OH WAIT THE POWER SWITCH IS OFF. Happened quite a few times while working on computer PSUs.
    Originally posted by PeteS in CA
    Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
    A working TV? How boring!

    Comment

      #3
      Re: NEC Multisync 1550v Dead (so's my brain)

      Originally posted by smason View Post
      So I turn the master switch ON, and push the power button.
      A friend gives me his friend's 32 inch TV to fix. He says there is no power LED at all. It is a Chinese Tatung with no english manual, schematics or service manual. Great, I'm going to be using every bit of knowledge I gained over 10 months to fix this.

      Go home, plug it in and sure enough no power. Push the front panel power on/off switch and nothing. So I lay out the tools, camera, multimeter, etc. Just about ready to unscrew the first screw and see a quarter size on/off button in the back.

      I replug in the TV and hit this button. The red standby light comes on. Okay, maybe the owner turned it off or I maybe pressed it to the off position by carrying the TV next to my body?

      Press the front panel on/off switch and the power LED goes green and it displays AV2 for a few seconds and goes black. Damn, 2 seconds to black. Okay I have done enough of that type of troubleshooting, so no worries.

      Then I cycle through the source button and for cable, it displays static. Odd! I haul out a dvd player, put in a movie and switch source. It plays the dvd. Wait 30 seconds, hmm, it is still playing the dvd. Leave it running for 2 hours, still working.

      Turn it off, turn it on. No problems. I leave it off overnight. In the morning, I turn it on and it plays the dvd no problem.

      I phone my friend and say I can't find anything wrong so I return TV.

      Apparently, neither of the 2 knew about the master switch button in the back. This TV was shipped by the owner's parent from the far east and the owner didn't know it had a master switch in the back.

      Now I know why the technical writers for the user's manual put in the following troubleshooting steps: check power, check connector, make sure the master power button is on, etc.
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      Comment

        #4
        Re: NEC Multisync 1550v Dead (so's my brain)

        I had the same with 2 NEC 1770NX models ,
        bought them in as dead and went to plug in power lead and see small on off switch right next to the plug point flicked the switch to on and hey presto
        both monitors fully functioning.
        Still running ok 1 year later .

        Comment

          #5
          Re: NEC Multisync 1550v Dead (so's my brain)

          See these on/off switches a lot on aftermarket ATX computer power supplies. Funny how many times when someone moves their computer, they accidently run their hand across the switch and shut it off. With manufacturers spending as little money as possible using cheap caps, it makes you wonder why they would spend the money on a on/off switch.

          Comment

            #6
            Re: NEC Multisync 1550v Dead (so's my brain)

            Originally posted by jetadm123 View Post
            it makes you wonder why they would spend the money on a on/off switch.
            A on/off switch that only cuts off ONE side of the ac line at that.
            Originally posted by PeteS in CA
            Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
            A working TV? How boring!

            Comment

              #7
              Re: NEC Multisync 1550v Dead (so's my brain)

              I once forgot to plug in the main ATX connector and shit myself thinking I had killed everything....
              "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
              -David VanHorn

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