Sony KV-4000 Troubleshooting Questions

[jhalphen]

Hi David,

Wow! that is severe indeed, the first picture is really revealing.

Just a gut feeling, but i would say that the KV-4000 is not necessarily the culprit.

OK, let's talk about your video sources, the KV is being used as a monitor running from a DVD, correct?

You're using a baseband video signal not an RF channel 3-4 out from the DVD, correct?

I would switch sources: NTSC out from an ATSC box, cable box, a second DVD player. Does the banding occur on other sources?

Is the banding fixed, moving, linked to picture content?
Permanent or random?

Have an oscilloscope connected to the KV's video input simultaneously and set it up as a WFM display, look at the signal in both H and V scan rates, do the bands show up simultaneously on the Sony and the scope?

Have you tried the DVD player on another video monitor? - all OK?

When the banding occurs, if you turn down the Chroma to zero, is it still there?

Do you have an NTSC generator, have you tried it on the Sony?

Try various signals with full black to white content: grey scale, convergence crosshatch. If the banding is related to luminance levels, video amp instability for instance, it could show up.

investigate silly causes: measure if there is a DC potential on the DVD's video out. One of mine did and it played havoc with my Broadcast routing switcher which is DC circuitry throughout. Inserting a big 470 Mfd Cap in the video feed solved the problem: crushed whites, smeary color & noise.

Keep us informed of the results of your tests.

Best Regards

jhalphen
Paris/France