Hi, I've replaced the HOT and failed. Checked all related areas, found nothing so I suspected the flyback failed under load. Replaced the flyback and HOT, but HOT still failed. Again I checked the HV caps and horizontal yoke (13 rings-good). B+ is at 150Vdc no load. Tried to check horizontal pulse to HOT but impossible, its too fast to see on the scope. Has anyone any suggestions or similar problem?
Thanks!
TP
Are you sure HOT B+ should be as high as 150v? The blue shaping capacitors 1.6KV or so often fail on Samsung sets. They are typically easily found by doing standard Horizontal/flyback waveform testing by reducing the regulated B+ with resistor or light bulb and looking at the HOT collector waveform on an o'scope.
Also some Samsung 25" sets have the old bad Zenith made picture tubes in them that shorted internally. Usually when it shorts the horizontal on these will crack the tube, but not always.
Your scope timebase can't handle 20uS (I think that's right...it's been awhile)?
Tom
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