What is this stuff?

[Boobericus]

I've been all over the internet trying to figure out what this puddle is and where it came from.
Any help would be appreciated. And yes I'm a complete noob to electronics.

 

[JimB]

Looks like some one was careless when changing the engine oil in their truck!

On a more serious note, I assume that the "puddle" is actually solid.
In which case it looks like some kind of potting compound, a hard setting resin used to protect electronic circuits and components.

Why it is poured on the circuit board like that is unusual.
It could be that what is under there is sensitive to the environment, humidity, dust etc.
Or it could be that the designer/maker of the board does not want anyone to be able to copy what is under there,
or to be able to repair it if it breaks down.

My best guesses, for what they are worth.

JimB

 

[Boobericus]

Thanks for the reply! Yes, it is very hard. The board is from a radio shack scanner. I've never seen this before. If they did it on purpose
pretty messy!

 

[Nigel Goodwin]

Thanks for the reply! Yes, it is very hard. The board is from a radio shack scanner. I've never seen this before. If they did it on purpose
pretty messy!

I agree that it appears to be potting compound/epoxy resin - and is presumably there to cover, protect or secure something - don't worry about it.

 

[sagor1]

If it was from a scanner, it is probably to protect/hide any circuit that would allow changes to the scanning ranges, such as cell phone frequencies. In the
"old days", scanners could listen in on the analog cell bands. Then, governments passed laws forbidding this. Since many scanners were modifiable, this potting compound probably met the "legal requirement" of dis-allowing any modifications to the receiving frequencies, so cell bands could no longer be scanned. This way, older boards that were modifiable could still be used, but "locked" from modification with simple potting epoxy.

 

[JimB]

If it was from a scanner, it is probably to protect/hide any circuit that would allow changes to the scanning ranges, such as cell phone frequencies. In the
"old days", scanners could listen in on the analog cell bands. Then, governments passed laws forbidding this. Since many scanners were modifiable, this potting compound probably met the "legal requirement" of dis-allowing any modifications to the receiving frequencies, so cell bands could no longer be scanned. This way, older boards that were modifiable could still be used, but "locked" from modification with simple potting epoxy.

That makes sense.
I think that you have the reason there.

JimB

 

[Boobericus]

Thanks again for the help. This is an old unit, so that makes sense. It covers 3 screws that hold a metal enclosure on the other side that you can't see whats
underneath.
At leasr I know what it is now, was driving me nuts trying to find out!

 

[KeepItSimpleStupid]

I agree with everybody. Knowing it was from a scanner helps. Listening in or cordless phones was possible too.

 

[unclejed613]

listening in on cell phones was possible with a TV with a UHF tuner that went up to channel 83 (while cell phones still used analog FM).... which is why they stopped making UHF tuners that went that high.... but a lot of people still had them.... you can still find them at flea markets and yard sales, but analog cell phones were phased out in the 1990s, and today all you would hear is bursts of noise.