Samsung PN42C450. Should Vs be shorted to GND?

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • MrBerga
    New Member
    • Dec 2012
    • 5
    • USA
    #1

    Samsung PN42C450. Should Vs be shorted to GND?

    Hey all. Working my way through a diagnosis. Basically if the X Main Board is plugged in with power, the TV will not boot. No sound, just repeated relays clicking.

    I noticed that Va does not get shorted to ground anywhere in the TV. On the SMPS and Y Main Board, Vs has high resistance to ground (20k ohms or higher). However on X Main Board, Vs has 0 ohms resistance to the chassis ground. Vs is shorted to ground ONLY on the X Main Board.

    I have a second X Main Board purchased from eBay with the same behavior. Can anyone confirm whether this is correct?

    Thanks!
    Tags: None
    • tom66
      EVs Rule
      • Apr 2011
      • 32560
      • UK
      #2
      Re: Samsung PN42C450. Should Vs be shorted to GND?

      Vs should not be shorted to GND.

      You have found the X-main to be bad -- very common problem with this set.

      Your new X-main may be bad too as it's sometimes possible for a cracked screen to damage them (if they are powered up when the Wii controller hits the TV.)
      Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
      For service manual, schematic, boardview (board view), datasheet, cad - use our search.

        Comment

        Previous template Next

        Related Topics

        Collapse
        • Document Archive
          Samsung Galaxy Book 2 Notebook Specification for Upgrade or Repair
          by Document Archive
          This specification for the Samsung Galaxy Book 2 Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the Galaxy Book 2 boardview and Galaxy Book 2 schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that any specification, datasheet, or download...
          09-07-2024, 05:50 AM
        • barry101
          Apple 820-3662 VCore shorted to ground.
          by barry101
          Hi, Would appreciate some help.
          I have an Apple Late 2013 15" A1398 MacBook Pro with Logic Board 820-3662.
          Get charger light but no fan spin or chime. No liquid damage.
          Found PPBUS and VCORE both shorted to ground. Other rails were ok.
          Removed VCORE MOSFETS U7310, U7320 and U7330. Found U7330 was in fact shorted.
          With the 3 MOSFETS removed, get PPBUS and fan spin. VCORE is still hard shorted to ground (0 ohms).
          Attempted voltage insertion on VCORE to locate short using bench supply set at 1.0 VDC and 4.95 Amps (max current for my...
          06-24-2025, 07:34 AM
        • mkdj
          Acer TravelMate P214 - N19Q7 main power rail shorted to ground
          by mkdj
          Dear all,

          I have taken out the motherboard of a Acer TravelMate P214. There is a short to ground on the main power rail (19V). I don't have the schematics or boardview for this board (DAZ8IMB1AA0 REVA). But I have found 4 MOSFETS close to the main power rail : 2 N-Channel and 2 P-Channel.

          I have checked resistance across each of the 4 MOSFETS. I have the following readings:
          Both N-Channel Mosfets: nothing odd

          P-Channel MOSFET number 1:
          source - drain : 117 kOhm
          source - gate: 96 Ohm
          gate - drain: 117 kOhm

          P-Channel MOSFET...
          08-20-2025, 06:08 AM
        • mkdj
          Lenovo Thinkpad L480 : 3VALW rail shorted to ground, but I can't find the shorted component
          by mkdj
          Dear all,

          Laptop is Lenovo Thinkpad L480 (boardview can be found in this badcaps topic). When pressing the power button the LED power light turns on, but nothing else happens.

          I removed the motherboard, checked for shorts on the main inductors. I found that there is a short to ground on the +3VALW_P rail (@PL201). I soldered a wire on the PL201 inductor, and I injected up to 1.3V with my power supply. Current drawn is approximately 3.2A.

          I used a small thermal camera to locate the shorted component. But nothing on the board heats significantly, except the...
          08-11-2025, 04:55 AM
        • Document Archive
          Samsung Galaxy Book Ion NP930XCJ Notebook Specification for Upgrade or Repair
          by Document Archive
          This specification for the Samsung Galaxy Book Ion NP930XCJ Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the NP930XCJ boardview and NP930XCJ schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that any specification, datasheet, or download...
          09-06-2024, 11:40 PM
        • Loading...
        • No more items.
        Working...