On Wed, Jan 6, 2021 at 12:29 PM Leon Robinson <leon-robinson@...> wrote:
Brad, I have had horses for over 40 years and I don't remember going around and smelling warm horse s*hit, have stepped in some and shoveled a lot.
Leon Robinson K5JLR
-------- Original message -------- From: Brad Thompson <brad.thompsonaa1ip@...> Date: 01/05/2021 9:25 PM (GMT-06:00) To: TekScopes@groups.io Subject: Re: [TekScopes] A note on PC boards, double and single sided.
Harvey White wrote on 1/5/2021 8:55 PM:
Printed circuit boards are generally made with one of two materials (there are others), either a paper epoxy (FR-3) or a fiberglass epoxy (FR-4). There are others, but these are most common.
Paper epoxy (FR-3) has a lower temperature tolerance, is not as mechanically stable, can be burnt easily, and is constructed of paper and epoxy holding it together. You see it in a lot of commercial (expensive or not...) equipment. It is mostly brown...
Hello-- Older imported electronics used a phenolic-based laminate-- typically medium to dark brown and liable to losing its traces when the repairer applied too much heat. Oh, and when overheated it smelled like warm horse s*it.
