Problem PVM-20m2u - Round 791 - 5v regulator Vertical Circuits

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  • Опубліковано 2 січ 2023
  • Ігри

КОМЕНТАРІ • 26

  • @v01dscum
    @v01dscum Рік тому +2

    keep at it mane, your vids got me into messing with pvms and crts, i prefer your general attitude and the way you explain stuff. thank you for the content you create youve taught me alot

    • @LameGaming
      @LameGaming  Рік тому +1

      Awesome, appreciate the kind words. 👍

  • @electronash
    @electronash Рік тому

    "Vertical Circuits" is a great name for a channel. Thanks. lol

    • @LameGaming
      @LameGaming  Рік тому +1

      Yes it is! Lol
      Ash if you start a channel with crt repair/tinkering let me know!

    • @electronash
      @electronash Рік тому

      @@LameGamingI've always wanted to do "proper" vids, for years, but I'm too shy to be on-cam, even if it's just tinkering with electronics.
      I can imagine how much work goes into some vids, while trying to actively repair, build, or code something, too.

    • @LameGaming
      @LameGaming  Рік тому +1

      @@electronash yeah, I can relate to that. Theres ways around being on camera but yeah... Editing sucks and is why Ive just been throwing crap videos up lately.... I just dont have the time for editing with work anymore.

  • @AkaAka-wc6or
    @AkaAka-wc6or 9 місяців тому

    I think the problem comes from the tube its self try rejuvenate if you didnt found solution
    try the tube on nother motherboard too

  • @riggel8804
    @riggel8804 Рік тому +1

    Maybe replace the power board?

    • @LameGaming
      @LameGaming  Рік тому +1

      Ive swapped in the identical one in the working 14m2u.... Same vertical issue 😢

    • @riggel8804
      @riggel8804 Рік тому

      @@LameGaming damn

  • @alfredocalzadilla7251
    @alfredocalzadilla7251 Рік тому

    Have you checked to see if you have any arcing around the demagnetizer coil?

    • @LameGaming
      @LameGaming  Рік тому +1

      After the initial recap and being able to power the unit on I heard arcing so took video at fastest fps I could with lights off and found the aquadag grounding fingers on the tube to be arcing. I hard soldered them to the frame with new ground leads and cleaned them and have noticed nomore arcing afterwards. None that I can detect anyway.

    • @alfredocalzadilla7251
      @alfredocalzadilla7251 Рік тому

      @@LameGaming I have a similar problem with my 20 inch series M pvm and discovered that there is some arcing between the top part of the tube and the metal shielding. Everytime the arcing happens, the image gets distorted; similar to what you are seeing but much worse. I still need to figure out how to disassemble the shielding for closer inspection without tearing the whole thing apart. It's a project for this weekend. I hope that you are able to find the issue! Since you already had arcing, I wouldn't rule that out.

    • @LameGaming
      @LameGaming  Рік тому

      @@alfredocalzadilla7251 I think the problem is they used those metal grounding fingers to ground the tube and they are just riveted to the metal frame, so 2 different composition metals only secured with rivets. Over time this weak connection/ground oxidizes and is nolonger able to ground the large amount of charge when the pvm is turned on. Thats the only time I noticed mine arcing was at startup. After soldering in the ground leads I dont think I have the issue anymore but wonder if that large arc may of damaged any sensitive IC or components on the board. Ive combed through everything the best I could with too many hours of testing to count. I wonder if one of the new caps I installed are faulty but still reading good esr. Ive noticed retrotech has moved away from using nichicons exclusively and uses mainly those red german branded caps.... I wonder if theres a known issue with some recent batches of nichicons?

    • @alfredocalzadilla7251
      @alfredocalzadilla7251 Рік тому

      @@LameGaming I think that a bad cap is unlikely to be causing the issue, specially if you used nichicons, rubycons, etc. It doesnt look like is a deflection issue either, but I am no expert and still learning a lot about crts with this pvm. I wouldn't move to wurth capacitors. I think that they are not any better than nichicons. If anything, they are just cheaper.

    • @alfredocalzadilla7251
      @alfredocalzadilla7251 Рік тому

      @@LameGaming If you are concerned about the capacitors you can also just go through the service manual and make sure that the capacitors that you replaced have the correct capacitance and voltage values (voltage can be greater but not lower)

  • @SamsungS-or1qf
    @SamsungS-or1qf Рік тому

    Picture breathing is usually tied to power delivery, check that the tube is getting correct and stable voltage(high voltage regulator). I’m betting faulty resistor not capacitor.

    • @LameGaming
      @LameGaming  Рік тому

      Wouldn't any HV regulation to the tube be in the flyback or are you talking about voltage to deflection coils?
      Schematic imgbb.com/0sns8bp

    • @SamsungS-or1qf
      @SamsungS-or1qf Рік тому

      @@LameGaming i might be talking out of my a.., but seems to be same problem as here ua-cam.com/video/hCopsoy0lQI/v-deo.html , picture is pulsating and can't keep the size. Anyway, I hope it works out!

    • @LameGaming
      @LameGaming  Рік тому +1

      @@SamsungS-or1qf That does look like a similar type of symptom but the power board on mine is putting out correct voltages and b+, also ive tried using the power board from my 14m2u which is working and has identical power board, same issue.... I just wondered about the 5v rail because V size and V gain circuit is fed 5v so replaced the 5v regulator but still only getting ~4.85v which I assume is ok.
      My picture is not dim either and can bump brightness and contrast up without any blooming of raster size
      My issue seems to be a gremlin playing hide and seek 😣 lol.

    • @SamsungS-or1qf
      @SamsungS-or1qf Рік тому

      @@LameGaming does it help to reduce contrast?

    • @LameGaming
      @LameGaming  Рік тому

      @@SamsungS-or1qf Has no effect on the issue

  • @iigsforevergraphicsandsoun5317

    I'm coming into this later but this isn't a breathing issue. I hear you say 'checked' capacitors but not replaced. One thing I've learned and feel like sharing (with respect) is capacitors and their performance are completely different under load than at rest with an ESR meter. Keep that in mind, which I'm sure you do. Secondly the words 'thermal expansion' come to mind. Am I right that the image is dead stable first 30-60 seconds that I saw? If so this is a dry joint issue -> caps.

    • @LameGaming
      @LameGaming  Рік тому

      Thanks for your insight, ive been so busy with work I havnt touched it. The problem is ive reflowed the entire board (surface mount components and all). Ive debated in my mind if I should recap it again.