Please second guess me guys

[Anonymous]

Lads

Would you take a look at these old telecoms boards please and give me a sanity check as to where you think there may be PMs? Would appreciate your input as I am receiving a lot of these in the next two weeks and I really don't want to be discarding them as low grade scrap if some of the older components contain PMs.

Thanks in advance guys.

Jon

 

[Barren Realms 007]

Possibly the tantalum capacitors might have silver. Other than that just the copper coils.

 

[Anonymous]

The tantalum being the beige looking caps correct?

 

[MarcoP]

The tantalum being the beige looking caps correct?

I believe them to be resistors, Rxx. He is likely referring to the aluminum case condensers, Cxx.

Marco

 

[Barren Realms 007]

The tantalum being the beige looking caps correct?

No. The 5 on the left board that look like aluminum. You can take one and squeeze it in the center and if it is soft it will all be aluminum but if it is hard it should be tantalum.

**Changed aluminum to tantalum**

 

[Anonymous]

The tantalum being the beige looking caps correct?

No. The 5 on the left board that look like aluminum. You can take one and squeeze it in the center and if it is soft it will all be aluminum but if it is hard it should be aluminum.

Huh? Frank can you write that in English mate? 8) 8)

 

[MarcoP]

So that's how you quickly know if they are tantalum (that's what the last "aluminum" should have been), they are hard.

Marco

 

[Anonymous]

Well I can't squeeze them. It looks like a tightly wound sheet enclosed in a plastic outer.

Edit: Bah ignore me - you mean the horizontal ones not the vertical ones don't you?

 

[Barren Realms 007]

The tantalum being the beige looking caps correct?

No. The 5 on the left board that look like aluminum. You can take one and squeeze it in the center and if it is soft it will all be aluminum but if it is hard it should be aluminum.

Huh? Frank can you write that in English mate? 8) 8)

Yea I ment tantalum for the second aluminum. I'll go change it. Sorry about that. 8)

Check the ones circled in red Jon.

 

[g_axelsson]

Except from the possible silver can tantalum capacitors discussed above I can spot some metal can transistors that could possible contain gold solder and bond wires. Cut them open to look inside for possible yellow metal.

For the capacitors, cut them open too. If you cut them in half you would either find a tightly wound roll of aluminum foil or a hard black slug of tantalum. If tantalum then the can might be made of solid silver.

You should actually be able to feel the difference quite easily, the aluminum capacitor is housed in an aluminum can and it is a soft metal. A silver can should be a lot harder.

Göran

 

[Anonymous]

They squeeze in a set of pliers and don't flatten completely it's like there is a core inside that prevents them from flattening out.

 

[etack]

None of them are Ta caps.

Eric

 

[FrugalRefiner]

They squeeze in a set of pliers and don't flatten completely it's like there is a core inside that prevents them from flattening out.

You've just squeezed them till the electrolyte has been forced out and you're pretty much down to the aluminum foil layers.
Dave

 

[Anonymous]

Fair enough guys- it looks very much like I will be consigning these to my low grade scrap! Hey ho, these are only the power parts I just wanted to double check first.

Many thanks to all who helped.

Jon

 

[johnny309]

The only "value" is in mettalic cap transistors....gold bonding wires and gold solder for silicon die attach...... rest is low grade scrap.

 

[Anonymous]

Thanks I don't have time in the warehouse for the lads to pick those off so I'll process it all.

 

[jason_recliner]

I'm a little curious as to what the boards actually are. There's an awful lot of magnetics going on in there.

 

[johnny309]

I'm a little curious as to what the boards actually are. There's an awful lot of magnetics going on in there.

Those are the days before "operational amplifiers" in form of integrated circuits are invented. The transformers seen on those boards a separation of voltage between input and output. They have an osscilator (which convert Dc voltage in Ac voltage ....at high frequency..... and then converted back to DC voltage).

 

[Anonymous]

Johnny thanks.

Would that put an approximate date on these?

 

[johnny309]

On the capacitorrs i see two diferent years '74 and '76 ....so I guess the year of production 1977 to1979(for the boards).