Zenith V3920W TV with Negative Picture

[CL]

I have a Zenith V3920W TV with a washed out, negative picture. I don't
have a schematic. CRT checks out OK on a Sencore tester. Luma/chroma IC
works in another set. Red, green, and blue driver and output transistors
check OK. Anyone have suggestions on what else to check? Please reply to
newsgroup. Thanks.

 

[Asimov]

"CL" bravely wrote to "All" (14 Sep 03 05:16:55)
--- on the heady topic of "Zenith V3920W TV with Negative Picture"

Is the video picture still negative with the colour turned down? Perhaps
a shorted inverting stage C-B junction in the video processor circuit.
But it could be an aft problem instead. Parasitic tuner or if section
oscillation due to a defective supply bypass could offset the aft. Maybe
a lifted ground wire. Is the sound okay?


CL> From: CL <chassleeSPAM@comcastSPAM.net>

CL> I have a Zenith V3920W TV with a washed out, negative picture. I don't
CL> have a schematic. CRT checks out OK on a Sencore tester. Luma/chroma
CL> IC works in another set. Red, green, and blue driver and output
CL> transistors check OK. Anyone have suggestions on what else to check?
CL> Please reply to newsgroup. Thanks.


.... This message transmitted on 100% recycled photons.

 

[David Harris]

CL <chassleeSPAM@comcastSPAM.net> wrote in message news:<3F63FA04.C3D85D6F@comcastSPAM.net>...

I have a Zenith V3920W TV with a washed out, negative picture.

Have you checked solder connnections on the secondary control
panel? I seem to recall that there are rivet sort of thingys that
connect the foil on the front and back sides of that board.
Otherwise I would trace the video signal and see if a coupling
capacitor is bad, such as C2251. Good luck.


David, on the Illinois prairie.

 

[CL]

David Harris wrote:

Have you checked solder connnections on the secondary control
panel? I seem to recall that there are rivet sort of thingys that
connect the foil on the front and back sides of that board.
Otherwise I would trace the video signal and see if a coupling
capacitor is bad, such as C2251. Good luck.

David, on the Illinois prairie.

Thanks for the tip. I'll check the rivets. I don't have a schematic, but I'll try to trace the
video. The luma/chroma processor IC works in another set.

CL