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How to get main board out of PTV

Discussion in 'Electronic Repair' started by BFriedl, Dec 23, 2003.

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  1. BFriedl

    BFriedl Guest

    Bill Jr and group,
    I found a short on the control board's B+ connector in this VS-6015 mits
    v10 set. Problem is, I cant get board out because of anode wire. Do I
    have to disconnect anode from all three guns to get this thing out to
    test, or can I just cut the wire and install a connector or solder it
    back together when im done? Doesnt seem the latter is a good idea
    though, with kV going though it. Need to get this board on my bench so I
    can find why B+ has 1.2 ohms resistance to ground on connector PA.

    PS. Set been off for 2 weeks...any HV left?
    PPS..Is the HV stored in the tube or the flyback?

    --
    BFriedl
    A+ Certified Technician
    AIM: UACybercat
    ** Bear Down Arizona! **
    ******* Go Cats! *******
     
  2. David

    David Guest

    Anode wire comes out of flyback if I remember correctly.
     
  3. BFriedl

    BFriedl Guest

    Indeed it does...doesnt really answer my question though, does it?
    --
    BFriedl
    A+ Certified Technician
    AIM: UACybercat
    ** Bear Down Arizona! **
    ******* Go Cats! *******
     
  4. BWL

    BWL Guest

    H.V. discharges within several seconds of power off.
     
  5. Bill Jr

    Bill Jr Guest

    BFriedl,

    The other posts are accurate.
    The anode connector simply removes from the flyback and the HV is reduced
    within about 10-20 seconds.
    Sounds like the 2SD1556 H.O.T. is toast.
    Usually caused by 130 volt B+ going over voltage.
    The power supply will probably be the culprit, after you replace the H.O.T.
    While you have the deflection board out, replace C5002 (always), both 100uf
    and 2200uf caps in the vertical circuit, the LA7838, the 1uf 200 volt cap
    off the horiz driver supply, and any other electrolytics that look suspect.
    Don't forget to clean all the black goo off the board.
    Then replace the caps in the primary of the both SMPS as well as the 270k
    resistors (R903, R914 with 1/4 watt versions), increase R918 to a 1k 1/2
    watt resistor, and do a light bulb test on the 130 volt line for regulation.
    It is best to disable the second SMPS (IC901 circuit by removing L904 while
    doing this test.


    Good Luck,
    Bill Jr
     
  6. It does indeed. You specifically asked how to disconnect the anode
    wire to facilitate the board removal. As David said, the lead pulls
    out of the flyback. (At least that's how I read your question)

    Alan Harriman
     
  7. BFriedl

    BFriedl Guest

    Then why all the hype over high voltage on the flyback??

    ps. Bill, already did your recommendations for the smps, and get +129v
    with bulb test on B+. Will esr caps on deflection board.

    --
    BFriedl
    A+ Certified Technician
    AIM: UACybercat
    ** Bear Down Arizona! **
    ******* Go Cats! *******
     
  8. Dave Moore

    Dave Moore Guest

    Hi Bill.
    Awhile back you mentioned that you might have
    the ufiche service manual for a Zenith PTV PVR4663RK
    http://groups.google.com/groups?hl=...kkqb.10549$

    Turns out that the schematic that was sent
    to me was the wrong one. It was for a 27" model
    that was very similar, but of course, the convergence
    section is radically different. No surprises there.

    I tried to email about this but may letter bounced back,
    even with the nospam removed.

    haven't seen you post for awhile so,
    I hope you're still around and that the offer is still good.
    Thanks
    =^^= DM
     
  9. Bill Jr

    Bill Jr Guest

    Dave,
    The offer is still good.
    I'll locate the fiche today and get back to you.

    Bill Jr
     
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