Black Epoxy

[amosfolz]

Hello,

I recently acquired a truck-bed full of miscellaneous electronics. It consisted of mainly wireless house phones and printers. I've come across some "chips" that seem to have gold bonding wires similar to what one can find within North & South Bridge Chips. The only difference is that there is not a fiber bottom that can be lifted up and off the board; the chip just sets directly on the board and is protected/covered in an epoxy that seems to have been dripped on top of it. I can see gold wires in some areas that did not get completely covered by the epoxy. I attached a picture I found online as reference as I don't have access to the boards at the moment. I apologize if this type of material has already been covered. I did not find anything using the search function.

I will try to upload some of the nicer boards I have gotten from the lot - if anyone is interested in what might be found in household phones.

Amos

 

[maynman1751]

If you continuously tap that black epoxy with a hammer, it will eventually break away revealing more gold wires.

 

[amosfolz]

If you continuously tap that black epoxy with a hammer, it will eventually break away revealing more gold wires.

Thanks for replying Maynman, I will try that with one of them and see what happens. I imagine some of the gold may be carried away by doing so though? Have you processed any of these with success? I may try to break away the epoxy as you've suggested, then cut out the small section of the board that the gold wires are attached to.

Amos

 

[yar]

The four pushbuttons are also going to have a silver contact in them as well.

 

[Snowmeow]

Cannot this black epoxy be pyrolized to ease the wires' extraction? (Naïf question, unconsider if it be too dumb)

 

[resabed01]

Cannot this black epoxy be pyrolized to ease the wires' extraction? (Naïf question, unconsider if it be too dumb)

That's exactly how I would do it.

 

[Pantherlikher]

I was thinking of pyrolizing them as well. I have a hundred or so house wireless phones with these. I also found that all, so far, cheap clocks that use a AA battery also has a board with the same epoxy.

B.S.

 

[g_axelsson]

I would incinerate to get rid of carbon too.

Göran

 

[meatheadmerlin]

I notice this type of black epoxy over chips in just about every kid's toy I take apart,
and also a surprising amount of contacts that look gold plated.
Maybe not so surprising with the desire to make toys stand up to the extra stress a child will put them through.

 

[danieldavies]

if you heat the epoxy with a heat gun and wedge a chisel under it, it comes off in one piece. collect them. when you get a fair amount i would incinerate and process them the same way as you would with n/s bridge chips.

 

[rickbb]

The four pushbuttons are also going to have a silver contact in them as well.

Would that be a solid or plated silver contact?

 

[patnor1011]

Always expect less, sometimes you may be surprised.