Quote:
Originally Posted by miniman82
It's not the RF section, this unit has a blank audio function to tell you if it's tuned in right or not. I played with the tuning slug, and it's definitely right on ch 3 where it should be. Posting pictures wouldn't do a lot of good, it really has to be video to see what it's doing but I'll try and describe what I'm seeing.
In dot mode, the dots dance around a bit as if there's a power supply problem. They never stay right where they should, like they do with my modern silicon powered dot/bar gen. In crosshatch mode the horizontal lines look good, but the vertical ones are shimmering and slightly wavy.
Bars actually look decent, just not the right colors. According to the front of the machine it's supposed to start out orange, but instead I have red. At the far right of the screen where green should be I instead have blues, so it sort of seems like one or more of the timing circuits aren't at the right frequency or something. I don't have a counter at home, but I do at work. Maybe I should take it in and do some fiddling?
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Not sure about the WR-64B, but in most color circuits, the phase of the signal determines the hue. Old Motorola color sets would display the color bars incorrectly - the problem was a uuf (pF) cap that caused a phase shift when warm. The gripe would be most noticeable when watching a football game- the grass field would shift from green to blue.
If it is the phase, look for out of tolerance parts - most notably resistors and capacitors, then check the slugs in the coils with a bright light - cracked slugs were a problem in early GE Color sets - the ferrite was inferior and would crack, shifting the color phase slightly, giving you either orange greens or color bars drifting through the picture. Years later, RCA had a problem with slugs that lost some permanence (their ability to behave magnetically) and you'd get garbled audio from the phase shift in the discriminator circuit. Rock the quad coil slug slightly, and the sound would come back to normal.
I'm also not sure of the tube complement -but if one or more tubes were supposed to have a shield, make sure they now have the shield. Also, put the chassis back in the cabinet of the unit to test - the case might affect it slightly. I have an Eico sig gen that will shift frequency slightly with a pressing action around the top handle.
I've never owned an older RCA color bar-dot generator, but I have an RCA WR-504A of Dad's that is rock solid (solid state) for going on 39+ years. Great little unit, used a mercury battery for operation, we converted it to NiCd.
Cheers,