my 19" amplifone tube has had a very severe burn to the phosphor and dot mask in the centre of the tube face, this has burned the dot mask through (you can see its meleted) and appears to have warped the surrounding dot mask in an area causing the same sort of colour anomolies that you are seeing. If the dot mask is not flat, it shifts the beam over to hittign the other colours in the triad. You can check this by displaying just one colour at a time and playing with the convergence. You will see that all three colours of phosphor are intact - what has changed is that there is an uneven beam field hitting it if that makes sense...
-- Andrew Welburn http://www.andys-arcade.com ----- Original Message ----- From: perfidious To: vectorlist@vectorlist.org Sent: Saturday, August 13, 2011 3:41 PM Subject: VECTOR: Amplifone Tube Issues I have been going through some Amplifone tubes recently and came across one I wanted to share. http://home.roadrunner.com/~salahiandson/ampb1.jpg http://home.roadrunner.com/~salahiandson/ampb2.jpg The deflection and HV are 100% on this machine. The yoke and focus rings are properly installed and the monitor is degaussed and converged good enough for testing. I attribute the above anomalies to color phosphor burn. I suspect a specific color of the phosphor has been burned away in these areas making them void of this color. I have very limited knowledge in this area so that is just a guess. The other suggestion has been some type of shadow mask movement but that does not appear to be the case to me for a few reasons. I have never seen this before with an Amplifone so I wanted some other input on this diagnosis. Thank you. --------------------------------------------------------------------------- ** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org ** Please direct other questions, comments, or problems to chris@westnet.comReceived on Sat Aug 13 12:24:17 2011
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