Fixed a Viewsonic VP930B today

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • PcarSBA
    New Member
    • Mar 2011
    • 1
    #1

    Fixed a Viewsonic VP930B today

    The monitor wouldn't turn on, only the green power LED would come on and flash every 5 seconds. Interestingly, the monitor did get recognized by the laptop so though VESA so the logic must have been somehow working. The inverter wasn't turning on at all. No telling if the

    The power supply put out 5.1 volts and 13.2 volts and the voltages looked reasonably good on the oscilloscope. On the logic board I found a good 1.8V and 3.3V at the two heat-sinked voltage regulators.

    I went ahead and replaced three caps on the power supply board: A 2200uF (16V) and two 220uF (25V) caps since I had matching types on hand. Mind you the caps didn't show any swelling or signs of electrolyte leakage. After that the monitor fired right up.

    What really stomps me is that the power supply voltages were very close to the spec values before replacing the caps and all looked well even with the oscilloscope. Also, the 220uF caps measured 216uF with the Fluke 123 scopemeter. I know this measurement is not equivalent to an ESR meter but still it leaves me wondering why the monitor didn't turn on before. Was it the 12V being too high and preventing the inverter to run?

    Thoughts
    Ingo
    Tags: None
    • PlainBill
      Badcaps Legend
      • Feb 2009
      • 7034
      • USA
      #2
      Re: Fixed a Viewsonic VP930B today

      The caps had high ESR, resulting in high frequency (probably about 100 Khz) ripple on the outputs. The LDO regulators were unable to filter this adequately, causing erratic behavior of the signal card.

      The 12V supply was slightly high because the inverter wasn't on. The 5V output of the power supply is regulated, the 12V is not.

      PlainBill
      For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

      Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

        Comment

        Previous template Next

        Related Topics

        Collapse
        • keepread
          Dell monitor PSU vs Dell laptop PSU
          by keepread
          Hi there!
          Someone gave me their old monitor, it's Dell S2715ht.
          The owner was using it when his PSU began to smell and then to smoke. It literally began to melt. He turned the monitor off, pulled the PSU, and ditched it because it was smelly even after it cooled. So I got the monitor but not the plug.
          Now, I tried to bring the monitor back to life, by plugging one of my many Dell laptop PSUs. They are of the same 19.5V, and the wattage of the laptop PSU is higher than that which the monitor is rated for. Visually, the socket on the monitor seems compatible, and the plug plugs...
          10-30-2025, 04:45 PM
        • wattage
          AOC AG493UCX 49-inch monitor - Firmware request
          by wattage
          Hello Badcaps Community,

          I purchased a preowned AOC monitor that is not working and out of warranty. It was sold as not working. I am looking for guidance on self-repair. In particular, I am after the firmware for the monitor. At the end, I have included monitor model information and links to pics and vids of the issue.

          The problem is that it will not display a picture on any of its inputs. And the on-screen menu does not appear. The power button works properly. It powers on with the remote as well. But the on-screen menu does not appear, even when not connected to any...
          07-13-2025, 04:41 PM
        • ant3202
          HP 27es - LED monitor - Monitor Flashing On - Off
          by ant3202
          Hi Everyone

          Lately I am experiencing the deja-vu incident on one of the led monitor like this.
          https://www.badcaps.net/forum/troubl...lashing-on-off

          The monitor is HP 27es LED Monitor
          https://h30434.www3.hp.com/t5/Deskto...e/td-p/6804692

          The monitor will randomly blackout and display no signal and will recover again.
          Sometimes need to power and off again to restore the display but...
          03-20-2025, 07:30 PM
        • momaka
          Wise Wing F199 19'' LCD monitor - recapped
          by momaka
          Looking through my repair pictures and notes, it's been a long time since I posted anything in the LCD monitors section. So here goes that.

          I'm dedicating this thread to one of the very first LCD monitors I repaired (if not the first one), which was more than 10 years ago now. The monitor is a Wise Wing, model F199. It's a 19” CFL-backlit LCD. I got it for free off of Craigslist in 2009 from a guy, who said he bought it for cheap from Wallmart and the monitor worked only for a little less than 2 years before quitting.

          When I saw the Craigslist post, I wasn't...
          08-24-2020, 10:58 AM
        • sew333
          Pc shutdown, monitor flickered with no signal after 10 seconds
          by sew333
          My pc:
          10850K stock 4800mhz stock Kraken X73 good temps
          2x16 GB DDR4 GSKILL 3000mhz XMP
          Seasonic Tx-850 Ultra Titanium
          Gigabyte Rtx 3090 Gaming OC
          Aorus Z490 Pro Gaming
          1 TB SSD


          4 weeks ago i launched Metro Exodus Enhanced and during cinematic advertisement part ( 30 fps ), pc just shutdown.
          Also monitor flickered with NO SIGNAL 10 seconds after shutdown. So only monitor and pc was affected.

          Next i pressed only power button, rebooted again and its fine again. Happened once and i cant reproduce.


          Power...
          02-22-2022, 10:27 AM
        • Loading...
        • No more items.
        Working...