24

I'm repairing an old TV with corrosion on the board. I'm having trouble reading the schematic from the manual. Here's the relevant section: I have two questions:

Do the thick bars on one side of the capacitor and the base of the transistor indicate those are connected together? I'd tone it out but the board is heavily corroded and I'm unsure if they should be connected. I've also seen these bars on other parts of the board, but the components there are not rated anywhere near as high as C451. I feel like that risks high voltage backfeeding through the other parts of the circuit.

What kind of capacitor is C451, and should it be polarised? The BOM lists it as a pp cap which I understand to be non-polarised, but I can't find any key that tells me what the dot on the symbol means. Let me know if I can provide any further information. Thanks

you are viewing a single comment's thread
view the rest of the comments
[-] jeinzi@discuss.tchncs.de 14 points 5 days ago* (last edited 5 days ago)

The horizontal bar is commonly used to indicate ground, meaning the part of your circuit you define to be at 0V. So they are all connected, yes.

I've never seen a capacitor symbol with a dot until now. I only know them on transformer symbols where they are used to denote polarity.

[-] boaratio@lemmy.world 8 points 5 days ago

I believe the dot on the capacitor indicates polarity, and you're correct about the horizontal bar being ground, but a single bar means local ground. Some boards have both local and global grounds.

[-] ProfessorHoover@infosec.pub 2 points 4 days ago

Thanks, I'll tie both of those together and see if I can find a non corroded source for the same ground.

this post was submitted on 07 Jul 2026
24 points (96.2% liked)

Ask Electronics

4191 readers
45 users here now

For questions about component-level electronic circuits, tools and equipment.

Rules

1: Be nice.

2: Be on-topic (eg: Electronic, not electrical).

3: No commercial stuff, buying, selling or valuations.

4: Be safe.


founded 3 years ago
MODERATORS