Ron wrote:
recovery! spec comes back and the crackles
and pops subside to an almost acceptable
level, but here's the rub they never really
subside completely, you are left with this
background crackle and if you leave the set
off for a few days it gets worse again, its
nothing specific as I've tried to trace it
it seems to come from all over IF AF front
end etc, I'm not talking backgound hiss, its
a crackle, sometimes quite bad other times
almost completely gone? is this a general
breakdown of componant material? ie carbon
in the resisters or similar? has anyone else
out there found this problem if so whats the
answer?

The most common reason for popcorn noise is bad resistors, but sometimes
you'll find some weird offenders (like bakelite tube sockets that have
arced over and formed conductive carbon paths inside). The best thing to
do is get a wooden rod and start tapping on resistors. Often the more
noisy of them will also be microphonic and you'll find it when you tap on
it. Use a dowel or something else nonconductive that will let you put
some good force on larger resistors.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."