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Philips PM3262 with ETH leakage

Discussion in 'Troubleshooting and Repair' started by SebaX75, Jan 24, 2012.

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  1. SebaX75

    SebaX75

    45
    0
    Jan 10, 2012
    Hi,
    I've bought an old Philips PM3262, all is working, but I heard a noise and smell of ionized air in the rear.
    I've opened it and the EHT is in dispersion, probably due to degraded isolation... it works as an ionizer on the edges toward the case; if I remove the eht from his home (so the case is not near) arches are formed only on the edges (they are visible only in the dark).
    This EHT is made from the classic series of diodes / capacitors to raise the tension, completely drowned in the resin. The electric arcs are formed between the edges of the EHT and the case of oscilloscope (isolated by a plastic film).
    I cleaned everything thoroughly degreasing (nitro solvent) and I've tried to increase the insulation with electrical tape, the noise and smell have decreased but are still present.
    Someone has idea on how to increase the insulation so that there are no leaks?

    Thanks,
    Sebastian
     
  2. f1ufp

    f1ufp

    2
    0
    May 1, 2012
    Hi,
    I've the same PM3262 since 1990 years and the same probleme for 1 year but i've never opened it; Last night the spot has disappeared and a new noise arrived so I stopped it; I think the THT crashed; i 'll soon open it.
    it bothers me because it is an excellent oscilloscope!!
    I think your's risks of ending like mine!
    Didier
     
  3. SebaX75

    SebaX75

    45
    0
    Jan 10, 2012
    Hi,
    I use it one time at month, so probably mine can work for more time.
    However I've reduced leakage using paraffin or wax on the rear (between EHT and case) and paint insulation for transformers above EHT case... now only a very little leakage is present.
    If you want to rebuild your EHT unit, here you can find how it is built and all components can be found in the catalog by Farnell: http://www.circuitsonline.net/forum/view/57917
    I hope it can help you.

    Bye,
    Sebastian
     
  4. f1ufp

    f1ufp

    2
    0
    May 1, 2012
    Hi
    thank's for the link, it's interressting; I'm going to try

    I' don't use my scope more than a few hours a month too...

    didier
     
  5. Henning

    Henning

    4
    0
    Nov 6, 2013
    PM 3262 connection problem

    I have an PM 3262 bought in the 80's.
    When switching it on I hear the click from a protection unit in the bottom rear and the led on the front is also blinking and then goes black. If I wait 5 min. the same happens.
    If I try again at once nothing happens.
    Any tips to what it might be
     
  6. Henning

    Henning

    4
    0
    Nov 6, 2013
    There is also a lamp on a board in the aft bottom blinking
     
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