Mica pad under power supply board?

[Mike Hanson]

I've occasionally seen amps with a mica sheet affixed to the case, below the power supply board. I'm wondering why this would be beneficial. I've googled a bit, but no reasonable explanation had been forthcoming. Any thoughts?

 

[martin clark]

Secondary / enhanced insulation to meet class 2 requirement..?

 

[Mynamemynaim]

I've seen it too and have always assumed it was an aid to insulation / safety

Quite often the standoffs are short and a heavy bash in the right place could cause the case to touch the board

 

[Mike Hanson]

Thanks! I also noticed it in some of Avondale's recent NCC300 builds, under the NCM1. It's probably a tighter enclosure than I'm using, so I'm probably safe without it.

 

[Mynamemynaim]

A lot of the Chinese built devices I take apart have that black "cardboard" to do a similar job I guess?
Just a cheaper solution to the same issue?

 

[OldSkool]

I fitted some polycarbonate sheet under my HackerNaps and mounted the standoffs for the PCBs to the sheet. It served a dual purpose of providing some insulation and also meant I didn't have to drill the steel insert of my modushop case, just the polycarbonate to match the pitch of the holes in the steel. The polycarbonate was some offcuts lying around at work so didn't cost me anything!

 

[davidsrsb]

Are you sure about mica, I often see a stiff clear plastic sheet used?
This would be an attempt at insulating the pcb from the metal casing