vertical lines in a Toshiba TV

[old_tv_nut]

Is that picture taken with no signal connected? If so, try connecting a signal and see if they dissappear. This will tell you if it's an RF interference or a conducted interference from horizontal into video on the chassis.

If it disapperas with a normal strength signal, I'd just forget about it. If it's still there, then you might try chasing ground connections between the circuits and also wire dress.

[vol.2]

Thanks for the reply.

Originally Posted by old_tv_nut

Is that picture taken with no signal connected? If so, try connecting a signal and see if they dissappear. This will tell you if it's an RF interference or a conducted interference from horizontal into video on the chassis.

It's 100% most definitely in the picture when a signal is connected.

you might try chasing ground connections between the circuits and also wire dress

I tried dressing some stuff, but not everything. I covered the entire flyback and also the hot lead into the tube with copper electrical insulating tape and it made no difference I could see.

I don't know how to "chase ground connections" exactly. Any guidance on how to do that?

[old_tv_nut]

Originally Posted by vol.2

Thanks for the reply.


I don't know how to "chase ground connections" exactly. Any guidance on how to do that?

Check ground connections from varioius circuits to the chassis to see that they are secure; resolder if needed.

[vol.2]

Originally Posted by old_tv_nut

Check ground connections from varioius circuits to the chassis to see that they are secure; resolder if needed.

I've reflowed the entire board already for sure. I don't think this is a loose connection thing. I suppose there could be a dodgy connection inside of a connector somewhere, but I kind of doubt it.

[ronl]

That could be what they called "jail bars" caused by a bad cap.Did you change c446? Its in the 178 v source for the video outputs.10uf 250 v.a common problem with fly back winding derived dc power sources.Hope this helps.RonL

[zeno]

Originally Posted by ronl

That could be what they called "jail bars" caused by a bad cap.Did you change c446? Its in the 178 v source for the video outputs.10uf 250 v.a common problem with fly back winding derived dc power sources.Hope this helps.RonL

DITTO
Start with C446. Its an all brand common problem. May as well change it on almost any SS set. Symtoms can be very subtle.

Zeno

[vol.2]

Originally Posted by ronl

That could be what they called "jail bars" caused by a bad cap.Did you change c446? Its in the 178 v source for the video outputs.10uf 250 v.a common problem with fly back winding derived dc power sources.Hope this helps.RonL

Originally Posted by zeno

DITTO
Start with C446. Its an all brand common problem. May as well change it on almost any SS set. Symtoms can be very subtle.

Zeno

I definitely changed that cap. I think I changed basically anything in the power supply, deflection area, and the RGB stuff.

Perhaps I need a better cap than the one I used, but it's a good Nichicon variety. Like I said though in my first post, I think I upped the temperature rating of most of the caps, so that might have reduced the ESR and leakage characteristics of them. I think usually higher temp resistance comes with an ESR hit.

I could try replacing it with a different one, or maybe try monkeying with the value to see if I get a different result.

If so, do you have any suggestions on what to try?

Thanks

Edit: I think it's worth mentioning that I also see the bars if I directly insert an RGB signal into the RGB mux chip on the video processing board. I did this as an experiment to see if I could inject RGB via the mux chip in place of the OSD signal and blank the screen to show a higher quality signal (I succeeded), but I did notice that I was getting the bars in the image this way too. This would leave me to believe that it's nothing about the composite input board or demodulation circuit that is effecting things at least. This set is a Toshiba, so it uses one of their optical isolator chips to get the composite video in without the need for an AC transformer to isolate the set (the optical IC has a separate ground).