Voltages for analogue RGB? CM8833-II/AKF17

[matburton]

tl;dr: What are the optimal voltages for analogue RBG and the CSync signal?

Recently I've repaired a Amstrad/Sinclair ZX Spectrum +2A, which has an RGB output port with CSync.

I have a Philips CM8833-II monitor (and an AKF17) so I'm hoping I can get it connected to one of those.

The +2A outputs quite high RGB voltages hence I'm trying to work out what voltages I should aim for and hence what resistors I need.

I've not had much luck Googling for a definitive answer for optimal voltages for these monitors, there's loads of results for SCART but I suspect that's not quite the same?

I have found some mention of connecting a BBC to AKF17 here, which also has 1.67V RBG outputs. The advise there was to bring the voltage below 1.4V suggesting a voltage of 1V. Is that optimal and would it be the same for the CM8833-II?

Mods: Feel free to move if I've created this thread in the wrong place.

[matburton]

As i can read, You have all explained in document that You linked. See page 13 & 14.

Do you mean this section?

Spectrum+2A/+3 RGB colour outputs require additional resistors. Without them the bright circuitry is not effective and the voltage levels into the SCART socket are too high.

Are you saying I the optimal voltages are the same as the SCART ones, 0.67V?
That doesn't seem to line-up too closely with the AKF17 link?

(Note none of my monitors have SCART ports)

[Daedalus]

RGB is commonly 0.7Vpp maximum across many standards, including the RGB from the Amiga, SCART and VGA. So connecting to a monitor that's intended for Amiga or SCART use, you would aim for 0.7V.

[matburton]

Originally Posted by Daedalus

connecting to a monitor that's intended for Amiga or SCART use, you would aim for 0.7V.

Sweet thanks Daedalus that's the confirmation I needed 330 ohms it is then!

(I suspect that'll work perfectly with my AKF17 as well, since it looks suspiciously like a 'cut-down' CM8833-II)