Circuit Board Carbon Arc

[Chris]

I have a 55 year old door chime clock and the board has carbon arcs which is
causing a short. I have seen boards with this problem before and they were
repaired using some type of filler. What is used?

Thank you for your help

Chris

 

[Bob Larter]

I have a 55 year old door chime clock and the board has carbon arcs
which is
causing a short. I have seen boards with this problem before and they were
repaired using some type of filler. What is used?

I'd scrub the board with alcohol & a toothbrush, then spray it with a
conformal coating. I can't think of any brandnames off the top of my
head, but I'm sure that many people here will have suggestions.

 

[baron]

Meat Plow Inscribed thus:

How do you get carbon arcs on a low voltage door chime board?

From the open contact points spark/arc. Though I would have thought
that it could be cleaned off.

 

[PeterD]

I have a 55 year old door chime clock and the board has carbon arcs which is
causing a short. I have seen boards with this problem before and they were
repaired using some type of filler. What is used?

Thank you for your help

Chris

This doesn't sound right, you can't arc with 24 volts. But, if it fact
it has happened, I'd recommend using a dremel to grind out the bad
parts of the board, and spray with a insulating coating, or even
fingernail polish.

 

[Chris]

How do you get carbon arcs on a low voltage door chime board?

The carbon builds up then it arcs across. If you are thinking that low
voltage will not arc, you are mistaken. Take a 9volt battery and put steel
wool across both contacts. It will cause a fire. My kids use to love doing
this at the kitchen table when they were young.


Chris

 

[Chris]

This doesn't sound right, you can't arc with 24 volts. But, if it fact
it has happened, I'd recommend using a dremel to grind out the bad
parts of the board, and spray with a insulating coating, or even
fingernail polish.

You can arc with 24 volts. That is like saying a car battery will not arc.
It happens quite often.

Chris

 

[GregS]

I have a 55 year old door chime clock and the board has carbon arcs which is
causing a short. I have seen boards with this problem before and they were
repaired using some type of filler. What is used?

Thank you for your help

I scrape out the black manually or with a Dremel tool.
I then coat the bad part with nail polish with a couple coats.
You could use epoxy if there needs more support.
Mesure the resistance across the arc points to
get an idea of the problem first.

greg