This entry was posted on Tuesday, June 23rd, 2009 at 11:32 pm and is filed under PCB FAQ. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
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What Is The Black Spot Looking Thing On The Pcb?
I opened my remote doorbell and looked at the PCB. In the receiver PCB I spotted a strange looking black spot, like a drop of black ink. Can anyone tell me what is this thing, is it to cover or hide a component or to make something moisture proof or it itself is a component (which it dosen’t seem to be). Can anyone help please.
3 Responses to “What Is The Black Spot Looking Thing On The Pcb?”
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June 24th, 2009 at 3:44 am
It’s drop of black epoxy which covers a chip containing the bell circuit. It’s for all those things, to hide chip and make it moisture proof. Chip is in ‘die’ form, no packaging
June 24th, 2009 at 8:13 am
sounds like moisture protection
June 24th, 2009 at 12:17 pm
Put the thing back together, now. It might be a drop of black ink. If it is not connected to anything and you don’t know how the receiver works, why not just leave well enough alone? If you really want to know what is going on try for a diagram of the unit, a circuit or logic diagram. On the other hand look for a circuit or logic diagram of a similar type of device to see what things look like and how they work.