vertical lines in a Toshiba TV

[Username1]

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Happy Sunday Morning! Have you by chance scoped out the posted wave forms on
the other side of the flyback, Q402 & Q404, H-Drivers for proper size & Shape
with no out of the ordinary spikes in rising of falling sides of their pulses...?

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[zeno]

A few things just in case.
Sams wave forms show 2 complete lines or frames.
The little isolation PS runs off the FBT. Check its filter cap.
Watch the lead dress, if to close to FBT it can cause this.
Remember cathodes high = dark pix, low =bright pix.
Scope should show a damped ring , refreshed (ping) at start of every hoz line.
That should show up on scope. Like I said it almost has to be there !
Also remember there are 2 or 3 grounds in this set.
AND since you re-capped check the polarity & value of every cap ! This is why
in most cases repair first then change a few caps & retest & so on.....

Zeno

[vol.2]

Originally Posted by zeno

The little isolation PS runs off the FBT. Check its filter cap.

I'm not sure which one you mean. Which pin on the flyback is isolated? 162V (pin 10)?

[zeno]

FBT pulse goes to T501, rectified by D501, filtered by C502.
Note some of the ground symbols are different. Gotta use the right one when measuring.
MOST of the set uses one hot GND. If the set was newer it would
probably use a SMPS and that would add a GND. But with those
the chassis GND is cold.

Zeno

[vol.2]

Originally Posted by zeno

FBT pulse goes to T501, rectified by D501, filtered by C502.
Note some of the ground symbols are different. Gotta use the right one when measuring.
MOST of the set uses one hot GND. If the set was newer it would
probably use a SMPS and that would add a GND. But with those
the chassis GND is cold.

Zeno

Ah! Okay, yes, I know about that. That's what I meant when I said the AV input. It's isolated by a optical input chip and then it uses T501 for its power I guess.

I did replace that filter cap, and I can't see any garbage in that circuit.

As far as I can tell, it's not in the video. I can inject and RGB signal into the Jungle IC and completely blank the video signal and the bars are still there

[vol.2]

Originally Posted by Username1

.

Happy Sunday Morning! Have you by chance scoped out the posted wave forms on
the other side of the flyback, Q402 & Q404, H-Drivers for proper size & Shape
with no out of the ordinary spikes in rising of falling sides of their pulses...?

.

To you too!

Q402 looks a bit weird. Q402, Q404, and the Video IC have all been replaced with new parts to check for any difference and none was found.

Also, the waveform on the other side of T401 looks correct. The rest of the set is not connected to Q402,404 besides the 134VDC supply, but even then only through a number of other components

All the parts in that whole section have been removed and checked for values with an LCR meter.