A few more actions and notes:
- L18 (Color Level Coil) - tried to adjust it against different L19 and L17 coil settings. At the extreme it amplifies the 4.08mc marker which does not help, for now I settled on when the color level is set to the minimum then setting L18 to have what would be the 3.63mc marker at minimum which leaves the 4.08mc and 3.08mc markers at the same level, this is also about what is done in the Zenith color level directions, example below. Note this image is with with the B&K 415 signal turned up, at lower settings this is a flat response.
- L19 (2nd Color Amp Coil) - when adjusting the slug starting with it at the top (nearest to chassis) the 3.58mc marker has the largest response (like a bell curve) with the 3.08mc and 4.08mc markers both lower. As I turn the slug down the 3.58mc start to fall, previously I kept turning the slug until the 3.58mc marker was just to as low as it would go. In doing this the 4.08mc markers would gain strength and throw the curve off, extreme example below.
- Today for L19 I instead only turned the slug down until the 3.58mc marker just fell below the 4.08mc marker, note the 3.58mc marker can be further decreased but at the expense of the over all curve, maybe this is a 1st of the two dips that would be seen with the VTVM.
- L17 (1st Color Amp Coil) - As I adjust this coil there appears to be a center area on the slug which brings the 3.58mc marker to it lowest and then starts to provides some over all curve gain, eventually the 3.08mc marker starts to drop off, I stopped right before this point. Further adjustment will cause the 4.08mc and 3.58mc markers to increase but then the 3.08mc marker will start to decrease.
- Note no combination of adjusting coils would yield individually strengthening the 3.08mc marker response.
- The strength level of the B&K 415 does affect the curve, would it be fair to assume that I should keep the level turned down so that at max color level there is no clipping?
- Several videos below, note I feel like the color amps are turned way down, i.e. the previous setting provided lots (maybe 2x) gain, maybe that is ok...
- Here is a video starting with the color level at minimum and going to maximum, note I have the B&K 415 signal strength set so that a maximum color level there is no apparent clipping (curve flattening): https://imgur.com/YFLdxcx
- Here is a similar video starting with the color level at minimum and going to maximum, but have the B&K 415 signal strength set to maximum: https://imgur.com/l563K5B
- Finally here is where I have landed for now: the response curve with color level set to the midpoint and the B&K 415 signal strength set to avoid clipping.
One option would be to pull the 8.2k resistor, add the 100k resistor and via a VTVM adjust the 2nd color amp coil to the 1st dip (nearest the chassis). I am confused by the directions, it notes to disable the sweep but to pass in the 3.63mc marker, the B&K 415 combines these functions so not sure how I would do this. What is the VTVM measuring, I assume overall voltage. Does a single marker act like a signal generator?
