Quote:
Originally Posted by Electronic M
If not adjusting A16 or A15 with color bar pattern should fix it.
My process is typically make sure there's a good tube, adjust 10 turns in either direction looking for barberpoling color then adjust for fewer bars until sync, then max out color level control and detune fine tuning till you get the weakest discernable color and check for barberpoling...If you get it readjust A's till it syncs with weak color signal, then return fine tuning and color level to normal settings and check your work by tuning to blank channel and back to test pattern and see if it barberpoles for a noticable period. If not it should be fine...This is a pretty common thing with RCAs.
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As recommended, I replaced V23, the 3.58mhz oscillator tube. Removing the grounded shield was difficult. I had to use an old fashioned pencil with a big rubber eraser on the end to push the tube out of the shield.
Immediately after powering it on, with zero calibration, I got color. The hue and saturation need calibration, but it is impressive how well the advice provided in this forum worked. Thanks!
RF reception for video and audio takes a few minutes to warm up, and AGC is also maxed out and yet no overload distortion, which suggests a weak IF amplifier. So I will try replacing RF and IF tubes to see if that helps. The vertical deflection and pincushion tubes seem worn out too, with the vertical size pot at max setting to fill the screen and vertical linearity is off, pincushion correction is also a bit wrong. So I will try replacing the vertical output tube and pincushion tube too.
Then I will revisit dynamic convergence, by exhaustively testing every component, replacing any that are out of spec, and I will try the procedures listed in the RCA handbook for dynamic convergence for TVs with 13 dials, as opposed to the more typical 12 dial procedure. The Magnavox has 13 dials, where the 13th dial controls blue “center shape”.