Objects on the screen are the correct shape and size, but have no green, and there is a very faint green smear off the right side of the image. It's not the kind of color problem that you would typically see when needing to degauss. It's as if the green signal is very weak (or too strong, since this is a backward Nintendo monitor - not sure how that works, exactly). It's the same kind of smearing you would expect to see if you've got a signal cranked up too high, but there's very little green present in the image, so that doesn't jive. I've already played with the G drive and bias, neither seem to make much of a difference. I'm wondering if one of the pots might be bad, causing the problem. Would like to check for presence of a green signal, but am not sure where to check or what to look for (signal voltage, etc).
Will check the B+ voltage ASAP - likely after work tomorrow. Already have the game room cleaned up for the evening, or I'd do it now.