Positive platinum test in mlccs?

[im1badpup1]

Has anyone ever had positive platinum test in mlccs?

I broke a couple on a small pcb board dissolved in AR and upon testing with stannous an instant dark brown coffee stain colour appeared. Is there anything else what may give me a false positive for platinum?

On the other side of the pcb theres a red led diode what where its mounted too tests positive for palladium. Its some type of sensor.

Ive several hundred so it wont be a bad thing if the testing comes up true.

Ive been concentrating on finding older pcb boards where possible i seem to be getting a lot of positive tests for palladium on boards built around the millenium, would this be about correct for when manufacturers transistioned from gold to palladium where possible, before then beginning to replace palladium with silver and nickel?

The gold plating seems better too, not dissolving off as fast as enig type plate would.

 

[anachronism]

Out of the many many assay reports I have had on boards I have had only one with Platinum showing.

Jon

 

[nickvc]

You need to precipitate the gold from the solution to get a better idea, one method is take a small sample of solution and add a few grains of ferrous sulphate which will precipitate the gold and then test with stannous.

 

[Lino1406]

Stannous chloride test is only an indication, don't treat it like a proof

 

[patnor1011]

Isn't platinum presence indicated by orange rather than "dark brown coffee stain colour"?