Sony KV-26XBR400 no picture

James Sweet 20 years ago

I'm working on the above mentioned set for someone. Symptom is no picture, sound is fine. At first it was intermittent and would respond to smacking it but now it doesn't, as is usually the case the owner continued to use it for about 9 months until it quit entirely.

CRT heaters glow, some HV is present as indicated by a small pop when I discharged it immediately after shutting it off, however the HV appears to be low and doesn't make the usual static sound when turned on. I forgot to take my HV probe with me when I was out there so I couldn't verify this though. I did touch up a few suspect joints, checked the semiconductors in the horizontal/HV section and didn't find anything suspicious. I'm planning on taking another look at it but bringing the HV probe but that'll have to wait a few days. Also there's a gray block connected between the flyback and the tube, at first I thought it was a doubler but then I realized there's no ground connection, no connections of any sort other than the red wire going in and another coming out. What function does this serve?

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David Farber 20 years ago

Are you sure about that model number? I cannot find any info on the web about it.

David Farber David Farber's Service Center L.A., CA

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James Sweet 20 years ago

Yes, I'm looking at a photocopy of the service manual right in front of me, it also lists chassis SCC-S47B-A, of course the schematics are so small they're illegible and there's really not much useful information other than alignment stuff.

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ray13 20 years ago

That is the H stat box, I believe that sony uses for trinitron models in older models they use to put a control in it but later they put the control on the CRT card.

You have to look for a bad capacitor on the screen supply, if the screen supply isn't high enough the Guns on the CRT don't put out beams to the screen. There are other things that could cause loss of screen supply but that is the most common. The cap for the screen supply is usually on the CRT card and is usually a 250 WVDC electrolytic. This is a flyback based supply so measuring the voltage may not give you a true reading unless you scope it.

Lastly now many times does the timer/sleep light flash when you first turn it on? Loss of vertical scan will flash the the light 4 times if I recall. If there is no vertical scan the set will kill the video so that a line won't get burnt into the screen.

Good luck KC8OJU Raymond Borowiak

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