Help Understanding ACC

[old_tv_nut]

"gets rid of all the other parts at the bottom and leaves only full bars top to bottom"

does not sound like keyed rainbow to me.

Sounds like primary and secondary bars (like SMPTE bars):
white, yellow, cyan, green, magenta, red, blue, black.

Is this what you had before "getting rid of the parts on the bottom?"

https://en.wikipedia.org/wiki/SMPTE_...Color_Bars.svg

[TinCanAlley]

Originally Posted by old_tv_nut

"gets rid of all the other parts at the bottom and leaves only full bars top to bottom"

does not sound like keyed rainbow to me.

Sounds like primary and secondary bars (like SMPTE bars):
white, yellow, cyan, green, magenta, red, blue, black.

Is this what you had before "getting rid of the parts on the bottom?"

https://en.wikipedia.org/wiki/SMPTE_...Color_Bars.svg

The bottom was a bit simpler than that, but yes. So this isn't a keyed rainbow pattern, darn. I found a generator on ebay that does the keyed rainbow, but not sure I want to add another generator to my collection for one purpose. I guess if it works, I can get rid of my Leader unit.

On another note, my tint is stuck in the poor control now. When it was working properly, it went from overly magenta, to more neutral and then to overly green. Each of those took about 1/3 of the pot travel, so to get from magenta to neutral, I had to move it at least 1/3 from fully counter clockwise. Now from fully counter clockwise it is magenta, then only a slight turn to neutral and another slight turn to green and the rest of the turn gets really green. The neutral section doesn't fully get rid of magenta or green, it's the best I can do to balance them.

I think I need to remove the subcarrier module and lift a leg of each capacitor and resistor for proper measurements. Then the same for the chroma module. Not sure about the coils and ICs on the boards (how to test or if they're even play a role in the tint adjustment).

[vol.2]

Originally Posted by TinCanAlley

The bottom was a bit simpler than that, but yes. So this isn't a keyed rainbow pattern, darn. I found a generator on ebay that does the keyed rainbow, but not sure I want to add another generator to my collection for one purpose. I guess if it works, I can get rid of my Leader unit.

The Heathkits do gated rainbow.

[TinCanAlley]

Okay, latest update.....

I decided to watch a few shows on the set last night and a couple of new issues came up that is pointing me towards the Chroma module.

Upon turn on the set, the tint was still not working as it should. The it was almost all the way counter clockwise in order to get decent skin tones. Anything more than a quarter turn and it went way into the green. Then after around 30 minutes the color flashed a couple times and it went B&W. I had to change channels and then back to get color again. This one is either the AFT or the Chroma module and possibly with the burst signal. A little while later, the color flashed again and this time it went full color saturation as if I turned up the color control to full. It stayed this way for about a minute or so, then went back down, but still higher than initially set.

So I know that the tone control is connected to the Subcarrier module and it manipulates the burst signal sent to the Chroma module. The color control is connected to the Chroma module directly. So if the tint setting is changing, and the color setting is changing, it seems the Chroma module is the culprit. The color disappearing might also be the fault of this module as well and changing channels resets the burst signal, or so I believe it does.

I will do what I can with the module as I can test all the caps, resistors and reseat the IC, but I don't know about the coils. Those coils are for Chroma Bandbass and Chroma Take-off. Not sure what those do and if it's even possible to test them in circuit or how to readjust one of them if I do something that changes its adjustment.

Might be time to look for a replacement module just in case.