Hi, im having an old TV , TC233 national and im learning anyway how to repair it ... the 1st problem were a horizontal white bright line and i assumed its from the vertical section and i changed the vertical ic and its worked , but the picture isnt good , i posted an image of the picture , what could be the problem ? , the vertical ic is AN5521. Horz Osc,Vertical,syn separtor ic is AN5435 ... these what i changed .
I would suggest the problem looks to be no black and white picture?, you have chroma, but no luma.
Quick thought! - some old TV's had a service switch inside, which had three positions - normal, frame collapse, and no luma - you 'may' have knocked the switch to the wrong position?.
Nigel, i think your correct, but the service switch is ok , i dont know where's the problem , a guy told me its from the "delay line" circuit and another one told me the sub-cont potonimeter is destroyed however i measured it its working ...
also i got some shocks from tv (3) , what do you recommend ?
im a final year electronics engineering student , i think its shame on me to not repair such problem !
hi ahmedragia21
visually check your Crt socket , pull out that form crt tube then see the terminal(focus), if greenish thats the problem replace it, A big wire from from flyback that the focus, one best thing to do is to open the socket to see the inner terminal ,it should be clean , you can also check the resistance across all crt socket pin(should be pullout from crt board) no resistance at all pin.
note:
thats only my conclusion on your tv problem.
Nigel, i think your correct, but the service switch is ok , i dont know where's the problem , a guy told me its from the "delay line" circuit and another one told me the sub-cont potonimeter is destroyed however i measured it its working ...
also i got some shocks from tv (3) , what do you recommend ?
im a final year electronics engineering student , i think its shame on me to not repair such problem !
Assuming you know what you're doing? (which doesn't sound likely if you have had three shocks already), check for signals on the luma delay line with a scope. As suggested, some old sets used to have a preset for adjusting the level driving it, that could be faulty as well.
Ignore all the rubbish about CRT bases and line output transformers, none of those have any relation to your posted problem.