Tek tds420 psu failure

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • boddax
    New Member
    • Mar 2013
    • 1
    • Italy
    #1

    Tek tds420 psu failure

    Hi , psu (Power Supply Inc ,model PS-1690) of my scope tds420 is faulty since no schematic and beginner in electronics i am here asking help. have desoldered the two mosfet they seems ok ,have some voltages on high voltage side but on regulation side (lm339 nothing) mesuring with no load
    and dont know how to start withoput stby button.
    where from i start to measure to reach the problem?

    primary mosfet :MJF16006A (seems ok)
    secondary mosfet:BUK454 (seems ok)
    custom chip tek 3 wires (i have 137Vdc on each wire)

    here the pictures



    Last edited by boddax; 03-18-2013, 01:04 PM.
    Tags: None
    • kc8adu
      Super Moderator
      • Nov 2003
      • 8832
      • U.S.A!
      #2
      Re: Tek tds420 psu failure

      last one of those i saw had the small caps dried out.replace them first.

        Comment

        Previous template Next

        Related Topics

        Collapse
        • MicroSMD Lab
          ASUS ROG Zephyrus GPU Mosfet repeat failure
          by MicroSMD Lab
          The board number is GU502DU. I repaired this a couple weeks ago and it came back with the same issue, same mosfet failed (PQH9201). I'm hoping that the GPU was spared this time.
          I used the same replacement part (purchased from Mouser) and I'm certain the soldering was done properly since it took just as much effort to remove as before. What could cause this same mosfet to fail? I'm thinking if it was unsuitable then the others would fail too. I looked for similar failures on YTube and the mosfet was replaced with AOE6930 in one instance and AOE6932 in the other but it's possible that the...
          01-10-2024, 06:36 AM
        • Jane
          How do you test MOSFET in laptops ?
          by Jane
          I tried to use this method:

          Testing an N-channel MOSFET:

          Step 1: Discharge the Gate (turn off the MOSFET)
          Place the black probe (COM) on the Source (S) and the red probe on the Drain (D). The multimeter should show no continuity (high resistance or "OL" – open line).
          Then, touch the black probe to the Source (S) and the red probe to the Gate (G). This discharges any stored charge in the Gate, turning the MOSFET off.

          Step 2: Charge the Gate (turn on the MOSFET)
          Now, place the red probe on the Gate (G) and the black probe on the          ...
          09-27-2024, 03:31 AM
        • npielawski
          MacBook Pro late 2016 (820-00239) with multiple failure modes.
          by npielawski
          I will just preface all this by saying that I have a fairly technical background but have never attempted SMD electronics diagnostics and repair before, I really like the idea and want to learn.

          I have a MacBook Pro late 2016 that died maybe four years ago. Over the course of 30 seconds, it got slower and stuttered, until it froze for a second and died. No click from the trackpad anymore, nothing. I started getting interested in electronics repair and decided to give it a shot, so I opened it, removed the battery (one cell was puffy), took out the motherboard and experimented with...
          10-15-2025, 01:53 AM
        • Nooy
          VGA MOSfet permanently shorted and loss of MOSfet pad
          by Nooy
          Hello everyone, I recently found this badcaps site and super Learn Electronics Repair youtube channel. And I wanted to learn how to troubleshoot power supplies and VGA cards and how to practice soldering, since I already have a properly defective piece of them. I am currently trying to solve two problems:

          I have a Gigabyte GV-RX460WF2OC-4GD type card. I managed to find the faulty MOSfet (AON6414A) on it, which I replaced. The card starts up, but after about half a minute, the MOSfet in the same position will be shorted again. Is it possible that the PWM controller driving the MOSfet...
          02-14-2024, 02:26 AM
        • redbaron1007
          Help identifying mosfet on Razer Blade RZ09 (CH570_MB_NT)
          by redbaron1007
          I have a Razer laptop (RZ09 MB# CH570_MB_NT) that has a shorted mosfet marked BND M03 E067 that I'm unable to find anywhere online. Does anyone either know what the part number is for this mosfet or have a schematic I can find it in?

          Backstory on the whole thing the laptop was plugged into a lamp at a hotel. The lamp got unplugged while it was charging and now the system won't power on anymore. I found the caps around this mosfet shorted and when I injected voltage into the caps the mosfet got hot and my bench psu was pulling 5A. Pretty sure this is all that's wrong with the laptop...
          1 Photo
          09-09-2025, 11:10 AM
        • Loading...
        • No more items.
        Working...