Home Theater Forum and Systems banner

1 - 6 of 6 Posts
I

·
Guest
Joined
·
0 Posts
Discussion Starter #1
First of all I do not know enough about tv's to sound smart so I'm not gonna try. oing way back to post number 152, you mentioned two different parts for the Pioneer Pro-118. One of them for convergence, the other for vertical deflection. What do each of these do? I realize that convergence is more or less where the colors (blue, red, green) meet on the screen to form "1 picture". What does the vertical deflection do? I have a terrible picture problem where the center top and bottom of the screen are squeezed together towards the center of the whole screen. Could replacing the chip STK4274 for vertical deflection fix this problem. That just seems to be the most logical answer. It could be a <$10 fix for a $6000 tv.
 

·
Plain ole user
Joined
·
11,121 Posts
Your post has been moved to a new thread to keep the forum more well organized. Each discussion of a new problem should be in its own thread in the proper manufacturer's forum.

Convergence control affects the shape, position, and size of each of the three images, Red, Green, & Blue. Deflection is the scanning of the CRT to produce the raster in the horizontal and vertical dimensions. Convergence is sometimes referred to as sub-deflection, as it is simply a modification of the horizontal and vertical scanning in each tube to get the three to match each other. Generally, a vertical deflection failure will result in a horizontal line with no vertical dimension to the image at all. Sometimes, vertical circuits will begin to fail with foldover distortion and/or shrinkage from top to bottom or from one or the other.

Regardless, I suggest just changing both if you are not sure. Also, replace any resistors that are heat damaged, repair any solder connections that are cracked or powdery looking, and replace any capacitors that are common failure parts.

In your case you have top and bottom pincushion distortion, which indicates a convergence problem. Vertical deflection problems would generally not form such a curve at the top and bottom.

The STK4274 was often used as a convergence output IC, but in your set is the vertical output, IIRC.
 
I

·
Guest
Joined
·
0 Posts
Discussion Starter #3
Well, first of all thank you for the quick reply. Sorry for the post in the "wrong area." I did not have enough time to really figure out where this post should go. I apologize for any inconvenience this may have caused. I will look into getting convergence parts and hopefully this will solve any problems I'm having. One quick question though. I have looked for conversion parts for this tv and have seen prices around $300. Does this sound right. I don't know if that's expensive for this part or not. Thanks.
 

·
Plain ole user
Joined
·
11,121 Posts
I am not sure what parts you are looking at but the chips discussed should be well under $100.
 
I

·
Guest
Joined
·
0 Posts
Discussion Starter #5
Is this convergence chip interchangable? What I mean by that is, can I use a part from a similar tv or is it tv specific?
 

·
Plain ole user
Joined
·
11,121 Posts
The part is a specific Sanyo OEM part. It was used in some other sets. Specifically, what are you asking?
 
1 - 6 of 6 Posts
Top