Afstemoog werkt niet goed in Philips B5X23A (Algemeen)

door tdperez , Eindhoven, 14.12.2021, 09:21 (1076 dagen geleden) @ Theo van Herwijnen

I am a beginner at this hobby and have a similar problem with the same B5X23A model. I have FM reception but the EM80 is barely visible. I've tried another EM80 tube and replaced the 470K resistor between pins 7-9, but still the eye is not moving and barely visible.

I have two questions:
1. What does this 25 pF capacitor across the FM antenna do?
2. In order to replace this capacitor, which voltage rating should I use? The schematic indicates a 500V cap, should I be strict about it? Also, how strict should I be about the capacitance? Will 22 pF do, or must I use exactly 25 pF?

Apologies for the noob question and for writing in English (I can read Dutch, but can't write properly)

Thanks!