No green cutoff/bias setting on TV

[japlytic]

On a portable TV from the late 80s, red and blue cutoff controls were fitted, but no green cutoff control was fitted.

Any reason why such a set would not have this control?

[Wizard]

Re: No green cutoff/bias setting on TV

Common on older sets. Till newer digital controlled allowed all RGB adjustment interpendent of G2 which I prefer.

Adjust the G2 or sub-brightness and sub-contrast knobs in the chassis (set the customer's brightness/contrast to midpoint) to get correct contrast/brightness then adjust to this master green on red/blue.

Be very *mindful* on the old CRTs. They don't take very well to radical adjustments just to bring back best picture, this will shorten the life *lot*. I learned early on it is better to leave stuff alone and do VERY MINOR adjustments just to juuuust get better picture than awful.

This is reasons why I do not *like* automatic kine adjustment for direct view CRTs. Kills them quick (death spiral).

Cheers, Wizard

[kc8adu]

Re: No green cutoff/bias setting on TV

to save the cost of 1 pot.
by the 80's crt's were fairly consistant in emission from new.
i remember a resistor where a bias/drive pot was to go on many boards.
and i still remember tweaking things to get another year or 2 from a customers dying crt.i would set the bias as low as i could and run g2 high.got rid of color smearing common with a weak crt.next call it was time for a crt or another set.