Strange picture issue

[spacies]

I have a machine here with a strange problem.

Both the tube and chassis PCB are new but the picture is bigger on the top half of the screen than the bottom.
Tube is horizontal.

Any ideas on how to correct this problem?

 

[grantspain]

what make and model monitor,its sounds like an adjustment issue(linearity)

[spacies]

Tube is a RCA. A48AAB37X01
Supplied from www.ceronix.com 
Service manaul is here http://www.ceronix.com/manuals/1492.htm

The chassis PCB is a Wei-Ya M820H  here: http://www.weiya.com.tw/products_detail.asp?le=english&fid=97&pid=106&top_fid=86

 

[grantspain]

sometimes the adjustment you require will be marked as east/west correction or vertical linearity-i just had a quick look on that chassis and it has vert-line noted,have tried adjusting this yet?

[spacies]

Hi,

Yeah tried that.

Maybe the 2 just aren't compatible?

[grantspain]

it all depends on the yoke impedence,you need to unplug your scan coils and read with a multimeter the resistance of the horizontal(red and blue) that then should match to the chassis-how bad is the picture?can you post a pic of the problem?
maybe there is another adjustment on the chassis itself somewhere

[Ken Layton]

So your picture looks like a trapizoid huh?

Try the pincushion adjustment (if this chassis has one).

Did you order the Wei-ya replacement chassis? If so did you check the yoke resistance first to be sure they were within the specs of the chassis you ordered?

If the yoke is the wrong one then you can order the correct matching Wei-ya yoke from Alva Amusement for just $18. That would be guaranteed to work correctly with your chassis.

[spacies]

Thanks guys,

I tried the v-line put dodnt make much difference.
I have just taken a better shot and highlighted a couple of things with the red arrows.



The left arrow is pointing to a dial with the : B+ ADJ under it.
And the right arrow has a red wire that can be jumped to another point and it has an N and W.

I didn't check the resistance. To be honest I dont know how, could you please advise?
The RCA tube came with its own chassis but it was a positive composite from what I was told and required soldering different parts to get working. I had the Wei-ya chassis here and tried it and it works apart from the picture prob.

[grantspain]

the b+ is factory set,don't touch it
the jumper is width either narrow or wide
to read the yoke you need a multimeter set on ohms and you read across the horizontal (red and blue) wires on the scan plug
i think ken is right in advising you to buy a new yoke and they are very easy to fit,you just have to be careful