jumpy screen with new chassis

[redfivexw]

I bought 4 wei-ya replacement chassis.  I just got done installing 4 of them.  3 were perfect, but 1 of them has  a jumpy picture.  The monitor is horizontal, and it jumps down from the top and springs back up quickly.  The chassis is brand new, is there something i am doing wrong with this one?  The chassis has 10 pins, low impedence.  the monitor has 10 pins and is low impedence.  I hooked up the RGB Black and white wires.  The picture looks flawless except for the jumping.  Could the chassis be defective?

[Ken Layton]

Are they all the same model? If so, does it need an isolation transformer?

Did you inspect the board for cracks/breaks in the foil traces?

[redfivexw]

they are all wei-ya, they are 1220H and 1220s (10pin and 8 pin neck).  I did not see any damage to the chassis.  I just dont want to call and say it is defective unless i am sure. 

[Ken Layton]

1220 needs isolation.

[redfivexw]

it is hooked up to an isolation transformer.  I just pulled the old chassis and plopped this one it, all the wiring is the same.  I will double check everything again this morning. 

[SirPeale]

What did you do with the old chassis, Jesse?

How DO you pluralize 'chassis' anyway?

[redfivexw]

I have all the old chassis here.  Most of the time, it is easier for me to just replace the chassis then to rebuild it. I have a few here that only had a bent picture here or there that i will re-cap, but when they just plain dont have any picture, i replace!  By the way, i have another question.  Can the monitor tube itself wear out?  I have a monitor here that has a good picture, but is bent in on both sides like this ) ( .  I replaced the chassis and it still has the same bend.  You dont really notice it unless there is a picture that has a box frame (you dont see it when playing Galaga but you notice it with ms pacman).  Anyway, seeing as how both chassis have the same picture, wondering if the tube is going bad? 

[SirPeale]

Some kind of yoke geometry issue.

[redfivexw]

how do you adjust it, i have never had to do that.

[grantspain]

does the chassis have a side pincushion adjustment pot?

[redfivexw]

I am sorry, i dont know where that would be, i dont usually get that far into the adjustments. Ken?

[grantspain]

would be marked as SPC or Pincushion,normally found on the main chassis but some have this adjustment on the remote board
hopefully your chassis has this adjustment

[SirPeale]

would be marked as SPC or Pincushion,normally found on the main chassis but some have this adjustment on the remote board
hopefully your chassis has this adjustment

Agreed - all depends on the chassis.  Some don't have it at all.