Dave, have you noted that this thing has not the EU CE mark, but the china export ones?
That was the first thing I saw on the back. China Export, Siglent will not be able to legally sell the model in Europe.
They can sell in europe normally.
Btw, Dave live in Au and there ChinaExport is just ok or what ever there need. EU directives are not valid in Australia.
I have also full report documentation about these, other is 52 sides and other 75 sides. Very detailed documents including of course all data how tested and results etc with laboratory document pictures but these stay behind my body. These can try ask from Siglent, they may give these or not.
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About rust or what ever. I have here opened and documented one SDG5082. No signs of this level of rust what Dave show. But, I can see also very very thin signs of "rust" on some metal cutting. This metal is somehow coated but cutted borders have open iron and it may slightly rust in some environment. Also I can see extremely light signs about this.
I suspect that it have happend in Shenzhen what is sometimes extremely humid/wet place. Perhaps in some time theu have been outside and wet before they arrive to Siglent electronic factory.
Outer case is aluminium.
Rf shielding seals are?
Internal body metal coating is undefined?
It may be better if do galvanic (electrolysis) coating after all metal work is ready and before use these in product line. But more this is like cosmetic problem and only inside unit -- UNTIL it is used in environment where where condensation may occur.
Internal can do also as old HP, aluminum casting and then the metal machining. But this body is then more expensive than whole this equipment now.
Btw, I did not see front panel teardown..
(oh yes but it can see in my images)
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But here certificates