Quote:
Originally Posted by bgadow
|
If the CTC-5 original configuration increases the black level with contrast increase, then it does need redesign. However, this wouldn't be the only way to fix it. A bias network attached to the cathode could fix that without reducing the DC coupling.
If the black level is keeping constant with contrast setting, and the problem is just asking for too much drive (beam current) at high contrast setting, then a reasonable fix could be to wire in a contrast limiting variable resistor in series with the customer control. This would give you an adjustment to compensate for video output tube variations.
It'll be interesting to see what mine does when I finally get it going.