08-01-2025, 01:03 PM
(This post was last modified: 08-01-2025, 01:10 PM by Mike Watterson.)
Yes, very common. Even if DC CRT coupling, there would be no black level clamp and AC somewhere. I think also BLC is easier for 625 than 405 (Neg vs pos video modulation). Even some early 625 sets were poor.
The 0.25 uF cap may have too much inductance. A ceramic cap has very low inductance, no matter if single layer (normal for 1 kV) or multi-layer (miniature 0.1 uF). Some RF circuits might even have four different capacitors in parallel for decoupling to minimise inductance (1 GHz to 20 GHz systems).
However likely total bandwidth is less than 3 MHz, so might make little difference. Also depends on how the two metalised plastic foils for the capacitor are terminated to the wires.
The 0.25 uF cap may have too much inductance. A ceramic cap has very low inductance, no matter if single layer (normal for 1 kV) or multi-layer (miniature 0.1 uF). Some RF circuits might even have four different capacitors in parallel for decoupling to minimise inductance (1 GHz to 20 GHz systems).
However likely total bandwidth is less than 3 MHz, so might make little difference. Also depends on how the two metalised plastic foils for the capacitor are terminated to the wires.
