# Can you help me identify this?



## Metaphore (Oct 24, 2015)

I got a few of these and have no idea what it is or what's the best way to recover PM from it. Any help is much appreciated.


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## Grelko (Oct 24, 2015)

I believe these are the same things but, newer versions. I haven't looked into it much yet. I have a dozen or so, except mine barely have any gold plating. I keep finding them on old stereo boards labled "amplifier" or "audio power module". It just seems to be a smaller board, that's on the main board like a large IC chip. They usually have a large heat sink attached.

Most of the ones that I have, are inside a black plastic cover, with the circuits attached to a piece of aluminum, covered in glue.

Some have MLCCs, or a couple small IC chips and certain types have bonding wires in plain view. The one is on the bottom right, is why I posted this picture. The larger grey ones are around 2.5" by 4.5"




Anyone have more information?


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## Metaphore (Oct 25, 2015)

Any ideas on how to best recover the values from these?


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## Grelko (Oct 25, 2015)

Metaphore said:


> Any ideas on how to best recover the values from these?



It depends if yours is made of aluminum or not. Remove everything from the board, then possibly reverse electroplate it, but I'm not sure how that works if it's made of aluminum, or what it would do to the green mask.

Other members would have much better information for this type of material, I haven't tried to process mine yet.


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## Metaphore (Oct 25, 2015)

The thing is very heavy. I don't think there is aluminum there at all.


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## Grelko (Oct 25, 2015)

Metaphore said:


> The thing is very heavy. I don't think there is aluminum there at all.



Check it with a magnet, it might be plated onto steel. You can file or scrape off a little and see what it looks like underneath. It could be plated onto copper or brass etc.


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## Anonymous (Oct 26, 2015)

What you have there is most likely Enterprise Telecoms equipment. Edit: or similar

The base is likely to either be copper or Kovar based. In very very rare cases the base is silver. The gold plating on those items is very thick indeed and if you remove the board from the inner part of the unit you will most likely see gold plate both underneath the board and on the face of the unit too.

Your first step is to scratch the gold down to the base and work out the composition of the base metal. Only then can you decide how best to process them but you have some good gear there. 

I hope that's of some help.

Jon


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## Grelko (Oct 26, 2015)

spaceships said:


> What you have there is most likely Enterprise Telecoms equipment. Edit: or similar
> Jon



The more I look at the picture, the more I agree with you Spaceships.

At first I thought it looked about the same as what I posted, but his looks more like a small heat sink attached to the back of the plate. Mine had a large heatsink completely seperate from the piece that it was screwed to, and the back of them pop off.


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## macfixer01 (Oct 26, 2015)

Grelko said:


> spaceships said:
> 
> 
> > What you have there is most likely Enterprise Telecoms equipment. Edit: or similar
> ...




The black modules you have Grelko are hybrid amplifier modules operating basically at audio frequencies, perhaps up to 35 kilohertz? The module Metaphore has appears similar to boards from satellite equipment, or some other comm equipment operating at those high gigahertz frequencies anyway.

Macfixer01


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## richard2013 (Oct 26, 2015)

Those are Telecom boards, the heavy metal plated with gold attached to the PCB could be aluminum or Copper.
The white components in the PCB are RF transistors which could have gold or aluminum wire bonds inside.


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## Metaphore (Oct 27, 2015)

richard2013 said:


> Those are Telecom boards, the heavy metal plated with gold attached to the PCB could be aluminum or Copper.
> The white components in the PCB are RF transistors which could have gold or aluminum wire bonds inside.



Looks like the heat sink is copper. 

What is it attached to the board with? Wouldn't come off with a hammer and chisel.


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## Metaphore (Oct 29, 2015)

So, would a hot sand bath followed by a hot HCL bath get the gold off these things?


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## Anonymous (Oct 29, 2015)

No it wouldn't. Do you have Nitric acid available?


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## Metaphore (Oct 29, 2015)

spaceships said:


> No it wouldn't. Do you have Nitric acid available?



I have a couple of liters, but it scares me.


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## Barren Realms 007 (Oct 29, 2015)

Metaphore said:


> spaceships said:
> 
> 
> > No it wouldn't. Do you have Nitric acid available?
> ...



Do a small test to find out what the reaction does and what you will come to expect from it then go to a larger material test and work your way up as you feel comfortable to. Just be safe.


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## Metaphore (Oct 29, 2015)

Just curious - why wouldn't hot HCL work on this?

One of these boards is 4" x 2.5" and weighs about a pound (guesstimate). Not sure I can get enough gold off of one to justify the cost of the nitric. How much nitric will I need to dissolve one of these?


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## Barren Realms 007 (Oct 29, 2015)

Metaphore said:


> Just curious - why wouldn't hot HCL work on this?
> 
> One of these boards is 4" x 2.5" and weighs about a pound (guesstimate). Not sure I can get enough gold off of one to justify the cost of the nitric. How much nitric will I need to dissolve one of these?



If it weighs about a pound you are looking at 1600-1800 ml of nitric to process it to remove the base metals and a lot shorter processing time frame.

Hot HCL would work on it but it will take a while before the copper starts going into your solution unless you kick it off with some 3% hydrogen peroxide and an air bubbler. 
Generally those are heavily plated and it is harder for the acid to penetrate through the pores of the gold plating than it would be for the board you have pictured. 

If you have a significant quantity of them to process the best way would be with a sulphuric cell after the board has been removed. If I remember right you said you were having problems getting the board off, you should be able to heat the metal up and the board should come off the heavy plated metal piece.


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## Anonymous (Oct 29, 2015)

Frank

I'm thinking of scoring the surface of the gold to base metal and using very weak Nitric. It can track under the gold and lift it off.

Jon


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## Barren Realms 007 (Oct 29, 2015)

spaceships said:


> Frank
> 
> I'm thinking of scoring the surface of the gold to base metal and using very weak Nitric. It can track under the gold and lift it off.
> 
> Jon



On the majority of it it should but I'm not sure it will allow 100% of the gold to come off without having to dissolve the majority of the base metal. Removing gold plating like that can be problimatic because the gold can be very stubborn to remove.


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## Metaphore (Oct 29, 2015)

Barren Realms 007 said:


> Metaphore said:
> 
> 
> > Just curious - why wouldn't hot HCL work on this?
> ...



Sounds like a plan! I'll start with hot sand to get the boards off, use a sulfuric cell on the heat sinks and AP on the boards.


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