On Tuesday, June 21, 2016 at 11:53:40 AM UTC-5, Michael Black wrote:
On Tue, 21 Jun 2016, wrote:

analogdial wrote: "can be damaged by static discharge. The input stage gets knocked out
but the radio still has enough gain to get some reception. "


Wouldn't it take EMP or outright dropping the
radio on the floor to cause that sort of damage?
Or just years of gentle, normal usage?

Yes and no.

MOSFETs are very sensitive to static electricity, their very high input
impedance (especially with no circuit built around them) does nothing to
put a load on the static electricity, so they can be punched out.

JFETs should be less vulnerable, but in more recent times I've seen talk
of JFETs being vulnerable as if they are MOSFETs.

That said, I was using a Delco car radio as a bedside radio, and at some
point it lost sensitivity on the AM band, initially I just thought it was
bad radio conditions. But eventually I changed the JFET and it was back
to "normal" sensitivity", so it actually can be a problem. I have no
recollection of anything that might have done the deed, this was a few
feet of wire inside so it wouldn't have been lightning.

Michael

www.jimstone.is EMP ...jimstone.is, 82.221.129.208