[Adam]

The 2 mechanical remotes on the left (SC600Z) don't work with this set at all, none of the buttons do anything. (But I think there is a 3rd version with a blue on/off button I don't have).

The one on the far right was the first electronic remote Zenith started using in '77, called the SC1000. (I have a '79 19" table CCII with the zoom that uses that exact remote, and used to have a '77 23" CCII console that used it.) With that remote all the buttons do what they say, except for the zoom which this set doesn't have. Which makes me think that somewhere out there is one that looks like that without the zoom that belongs to my set. And because 5 of the buttons do something, I don't think it used a mechanical remote (which I've only seen with 4 buttons - unless they had something like they used to have with the older SC600s where you had to hit 2 buttons in sequence to adjust the tint).

That shorter electronic remote, the SC800, I think is newer and went with the first System 3s. All the buttons on it do what they say with my set - except for the volume. The volume just seems to have 3 positions and one button will cycle through them (like on the remote on the far right). With this remote, the 'volume lo' button does that and the 'volume hi' button does nothing.

The Zenith factory manual just says this set uses "SC600". I think that there might be a SC600 version of that SC1000 electronic remote with only 5 buttons that went with this set - but I have no definite proof that such a remote existed.