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Iwatsu SS-5711

Discussion in 'Troubleshooting and Repair' started by Sinewave, Feb 15, 2013.

  1. elebish

    elebish

    177
    12
    Aug 16, 2013
    Only an old fashion cap checker that checks for leakage at 600 vdc will work. An ESR meter (I have one), will not find this problem, besides they only work on values of 1 Ufd or above. Ed.
     
  2. Sinewave

    Sinewave

    119
    1
    Feb 15, 2013
    Hi Ed, I think I'll replace as many poly caps as I can then in that case. Previously, I did replace 19C51 and 19C52 when I replaced some electrolytics in the power section, as one also had a split.
     
  3. elebish

    elebish

    177
    12
    Aug 16, 2013
    I have a 5711 Iwatsu that had the same problem. Replace 19C68 ([email protected]) and 19C64 ([email protected]) on the Z axis board then readjust focus 1, focus 2 and astig. Ed.
     
  4. elebish

    elebish

    177
    12
    Aug 16, 2013
    Let me know if replacing 19C64 and 19C68 fixes your problem. Ed.
     
  5. elebish

    elebish

    177
    12
    Aug 16, 2013
    It's a fast switching schottky! Ed.
     
  6. Sinewave

    Sinewave

    119
    1
    Feb 15, 2013
    I've been slow, not fitted the components yet, but I do have them.
     
  7. Sinewave

    Sinewave

    119
    1
    Feb 15, 2013
    I'm trying to check 19C43, I can see it on the schematic, but I just can't find it on the board. Is it on the same board as the rest of the CRT Z amp board?
     
  8. Sinewave

    Sinewave

    119
    1
    Feb 15, 2013
    Just found it, replaced it.

    So tonight and it's taken me a long time to do (have a 1 year old son which keeps me busy) I've replaced all you suggested and it works!

    Nice crisp sharp trace!

    Thank you very much for your help. I'd love to be able to return the favour.
     
  9. elebish

    elebish

    177
    12
    Aug 16, 2013
    Replace 19C43 and 19C64 with like values (630 vdc) and readjust 'focus 1, focus 2 and front panel focus. These caps are known to break down with voltages less than rated as the years go by. Ed.
     
  10. elebish

    elebish

    177
    12
    Aug 16, 2013
    When one gets to be my age, being useful to others is reward enough! Ed.
     
  11. Sinewave

    Sinewave

    119
    1
    Feb 15, 2013
    For the sake of it, I'd make the 2.5kv test as I have a probe, but I'm unsure where to test. The photo in the manual doesn't show crt pin 2 very well, so since it all works, I'm leaving it well alone.
     
  12. elebish

    elebish

    177
    12
    Aug 16, 2013
    Let me know if replacing the 2 caps remedies the problem. It should but you may have to readjust focus 1 and 2 and the front panel focus along with the astig adjust. Adjust the front panel focus to the center position before making the other adjustments, then the front panel focus should be pretty much centered when properly focused. Collapse the sweep and you should have a nice round dot when adjusting the astig. Ed.
     
  13. Sinewave

    Sinewave

    119
    1
    Feb 15, 2013
    I'm not sure if it were those two caps alone, but the focus is nice now, I'll just have to centre the focus and make the other adjustments inside to make it focused with the front panel focus control centred.
     
  14. elebish

    elebish

    177
    12
    Aug 16, 2013
    I'm pretty sure those 2 caps were your problem as they were my problem. Do not over adjust the intensity pot on the Z axis board. Ed.
     
  15. rasantos

    rasantos

    1
    0
    Feb 22, 2019
    Very nice Mr. elebish!

    Thank you!

    I was just seeking for help and found this thread. My workplace SS5711D oscilloscope has the same issue. I hope it will be the same solution. The line which should have -297V (from HV board) is presenting just -56V. It may be due to 19C68 capacitor if its leaking current, but I will check 19C64 as well.
     
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