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I need help with an old RPTV. Slight image distortion. Possible convergence issue? (Moved to...

post #1 of 7
Thread Starter 
As per a response, I moved this post into another thread... I can't find a way to delete this thread so I've just edited it. Apologies!

http://www.avsforum.com/t/695922/dont-dump-your-crt-rptv/11880#post_23752924
Edited by Mister Laz - 9/19/13 at 3:24pm
post #2 of 7
Thread Starter 
Added the pictures.
post #3 of 7
Looks like the geometry needs to be realigned. You can either use a grid overlay or a geometry test pattern like this one: http://www.cepro.com/images/uploads/4k_isf_test1.jpg.

You can google for a service menu but it sounds like you may have already found the right part of the service menu. It is similar to the convergence adjustment screen but you can move all three colors to correct geometry.

The convergence chips went on my Hitachi awhile back and it completely throws the geometry out of whack, far more than what's on your screen.
post #4 of 7
Thread Starter 
Oh nice! Interesting. Okay I'll have to have a gander at the service manual to see which option I use to get to the geometry alignment part of the television and see if I can't get that sorted out. Thank you, kindly!
post #5 of 7
Thread Starter 
I read forward and backward through the service manual and it doesn't mention anything about a geometry correction screen, and Google was no help either. From what I can read and find on Google, the geometry is fixed via the convergence grid screen. It looks like I'm going to have to make my own grid overlay with tape and string and manually straighten every point out. A bit of a daunting task but I'm not sure of any other way unless someone more experienced is able to shine some light.
post #6 of 7
You can try posting your questions here :
http://www.avsforum.com/t/695922/dont-dump-your-crt-rptv/11340
post #7 of 7
Quote:
Originally Posted by Mister Laz View Post

I read forward and backward through the service manual and it doesn't mention anything about a geometry correction screen, and Google was no help either. From what I can read and find on Google, the geometry is fixed via the convergence grid screen. It looks like I'm going to have to make my own grid overlay with tape and string and manually straighten every point out. A bit of a daunting task but I'm not sure of any other way unless someone more experienced is able to shine some light.

Yes, the service menu geometry screen should look like the convergence grid screen but it will allow you to adjust the lines on all three of the guns to remove the bends in the picture.

You might try a geometry test pattern if you can hook up a laptop or desktop computer in order to show the image. I think the Hitachis allow you to bypass the internal grid when doing the geometry adjustments allowing you to use whatever grid you want. The Toshibas might be different.
You might also find geometry test patterns on calibration dvd's like Avia and Dve, though I haven't used them so I don't know for sure what is included. That would also require the ability to bypass the internal grid.
I tried a thread grid once but it didn't work very well, a string grid might be better. And yes it is a lot of work tongue.gif

I eventually had a grid (a pdf image provided by a forum member) printed on a clear material of some sort but I never got around to using it.
Some one on here may have an image of the the grid for your toshiba that you could have printed onto a clear material of some sort.

The Don't dump your crt thread is indeed the best place to get help with these sets.
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