bad screen geometry

OldFoo · Post by **OldFoo** » Sun Jun 12, 2011 2:01 pm

hi !

i have an offer to buy a used naomi universal. but it is not really tha cheap. it's technically and visually alright, but the screen has some serious geometry issues like seen below :

http://imageshack.us/photo/my-images/94 ... 12072.jpg/

now i know that the picture not fitting the screen is easily adjustable, but i'm afraid about that "wave" on the right side as it is quite assymetrical.

is this still doable with the screen options to fix this or does this need some servicing / cap exchange etc.

i would be sincerely grateful for any help as the seller is getting anxious.

OldFoo · Post by **OldFoo** » Sun Jun 12, 2011 7:27 pm

just looks like the horizontal hold is off

OldFoo · Post by **OldFoo** » Mon Jun 13, 2011 9:30 am

shouldn't there be in this case an identical wave on the left side also ? or is it possible for it to be assymetrical.

OldFoo · Post by **OldFoo** » Mon Jun 13, 2011 9:05 pm

try your adjustments first

OldFoo · Post by **OldFoo** » Sat Jun 18, 2011 10:58 pm

i tried the adjustments today and this is the best i could do :

https://picasaweb.google.com/mastkopato ... 3795930082

https://picasaweb.google.com/mastkopato ... 2863366786

https://picasaweb.google.com/mastkopato ... 4717839874

pretty bad i would say.

one thing that made me suspicious - according to this link:

http://wiki.arcadeotaku.com/w/Sanwa29e31s

i have a sanwa screen as i have identical stickers. although on

my chassis i have "nanao" written down and it looks like in the

manual for the nanao 2931.

is this possible that someone switched the sanwa chassis for

a nanao one? i read somewhere that this is impossible as the

screen have different impendances.

OldFoo · Post by **OldFoo** » Sat Jun 18, 2011 11:27 pm

this is getting even more weird. when i look at those two pictures:

my pcb:

https://picasaweb.google.com/mastkopato ... 3657775346

ms9 pcb:

http://wiki.arcadeotaku.com/images/4/48 ... ispots.jpg

it looks like i have a ms9 pcb installed? i'm horribly confused.

should i try to exchange the caps on this or should i just toss this into the bin and buy a rodotron chassis?

OldFoo · Post by **OldFoo** » Sun Jun 19, 2011 11:18 pm

Yeah, you have a Nanao MS9 chassis which is 15KHz only (kind of chassis you find in an Egret II or in an Astro City). And if the tube is a 29E31S then it's a wrong combo.

OldFoo · Post by **OldFoo** » Mon Jun 20, 2011 7:42 am

is it possible that this might permanently destroy the tube or chassis ?

yesterday i tweaked around a bit more and got to a quite decent picture:

https://lh5.googleusercontent.com/-5xNY ... 619098.jpg

although the sides of the screen still "flow" on movement:

https://picasaweb.google.com/lh/photo/V ... directlink

but i have found some expert on crt's who will exchange the caps for me so this might get better.

although before i do that i would like to confirm that this is actually a good idea. because otherwise i might end up better selling the chassis as it is and buying a rodotron 666a.