Newbie needs help with Television, Short/ No Vertical Sweep

[fausto408]

tv vertical sweep

I am not sure if this is the right place to post this but I a student who is trying to save a few bucks by fixing his own tv. It is a Panasonic 27 inch tv, model no. CT27G23W. The sympton seems to be a short vertical or no vertical sweep at all. Meaning the top and bottom of the screen seems to be sqeezing towards the middle. I only managed to diaognose it after reading this page:

**broken link removed**

I know nothing about fixing televisions but I say its worth a shot since I like opening things up and finding out how they work. I did a search on these forums and a schematic manual turned up specifically for my model, but I wouldnt know how to read it even if my life depended on it.

If this is the wrong place to post, then feel free close this post or if you can direct me in the right direction, I would greatly appreciate it.

Also, would it be worth it to just take it to a TV service shop? How much should it run me? Thanks guys.

Fausto

 

[sinip]

panasonic tv no vertical sweep

This is exactly right place to ask, but since you said that you can't even read schematic diagram... Sorry, don't know how anybody could help you, without putting your property or your life at risk.

Anyway, you would get only one very thin and bright horisontal line if there was no vertical deflection at all. This way, you probably have the case of dried out electrolytic capacitors in vertical deflection stage.

 

[fausto408]

no vertical sweep

LOL. Thank you very much for your concern Sinip. As far as damaging the property, Im not worried about it. (As far as Im concerned, shes already a goner!). But if you think I am risking my own life then maybe I should leave it to a professional. Would I have to work on the television while the power is on?

I am very comfortable with computers, (probably will go for my A+ certification soon), I just dont have a too much soldering experience (The only time I recall is when I was building one of those famous Cable Box Descramblers when I was like 12, (now 22) .

As far as the symptons of the tv, it changes back and forth from full, regular screen to a thin horizonal line, but never all the way thin. You can always see some of the picture, maybe an inch or two thick. Would I need a lot of tools before I would event be able to attempt this?

 

[VSMVDD]

tv no vertical

your problem is capacitors near to the vertical frame drive ic have dried up

replace them

and also resolder the whole area
look for the schematics for the set you have
you can find many of them thru google
by typing the maker /model numbers
some you may need to buy but visit a local old guy shop is best
and blagg a photocopy

youll find referance librarys have a full set of diagrams and update them regulary
i live in Glasgow here we have the Mitchel library a very good read

 

[fausto408]

vertical out television

I actually already did find the schematics on this post:



The hard part is trying to decipher it. Im sure if someone could point me in the right direction on the pdf file, I could better understand the layout on my television.

 

[sawwa7]

no vertical sweep on tv

I actually already did find the schematics on this post:

**broken link removed**

The hard part is trying to decipher it. Im sure if someone could point me in the right direction on the pdf file, I could better understand the layout on my television.

hi
the vertical output stage using IC451 and u have to resolder it and the components around it , also replace the electrolytic caps around this IC and here's a pic to show u where to start , hope it'll helps
Kind Regards

 

[fausto408]

diagram of vertical sweep section complete

thanks for the reply sawwa7, but I still seem to be having trouble locating IC451. I thought I had located it in the top right corner of the board (Based on the "Placement Chart" page 4 of 12 pdf file) but it doest seem to look like anything in the .gif you posted from the same file. Is there anyway you can point out its location on the "Placement Chart" of the pdf file?

 

[sinip]

how to fix tv vertical sweep

LOL. Thank you very much for your concern Sinip. As far as damaging the property, Im not worried about it. (As far as Im concerned, shes already a goner!). But if you think I am risking my own life then maybe I should leave it to a professional. Would I have to work on the television while the power is on?

I am very comfortable with computers, (probably will go for my A+ certification soon), I just dont have a too much soldering experience (The only time I recall is when I was building one of those famous Cable Box Descramblers when I was like 12, (now 22) .

As far as the symptons of the tv, it changes back and forth from full, regular screen to a thin horizonal line, but never all the way thin. You can always see some of the picture, maybe an inch or two thick. Would I need a lot of tools before I would event be able to attempt this?

Well, in this case, you don't actually have to do anything while the TV is on (in some cases, when you need to do some adjustments, the TV must be on). So, you can try to fix it while off, then switch it on to check if you got it right. And when I say off I mean off by mechanical mains switch or by pulling the plug out of mains socket, not off by remotre control! You should certainly need soldering iron (18 or 20W would be ideal), soldering alloy, new set of electrolytic capacitors for vert. out. stage (pay attention to polarity and rated voltage (higher voltage than original is ok, lower is NOT!!!) and then also resolder whole affected area, because based on your description you could have "bad solders" problem, especially if the TV reacts on physical pressure to main board while on (see, in this case TV must be on). So, unless you do something very stupid, you should be ok (and you can't sue me anyway, I'm not in the States)
BTW, A+ is something I am considering for years now, but never had enough time, or actual need, to go for. But, one never knows...

Anyway, IC451 should be on heatsink, so just look for it and IC451 should also be written on top or bottom of mainboard, next to actual IC.

 

[jorgeteo21]

ct27g23w no picture

Hey did you ever fix your tv set yourself I am having the exact same problem, If you did fix it yourself how did you do it? what part did you actually replace? HELP!!