Re: CK722 Fans
Watson A.Name - "Watt Sun, the Dark Remover" wrote:
"Jon Elson" <jmelson@xxxxxxxxxxxxxxxx> wrote in message
news:42920CBA.1040808@xxxxxxxxxxxxxxxxxxx
Henry Kolesnik wrote:
After my first real summer job in 1955 working on a CNR steel relay
gang in
BC I stopped in Edmonton and bought two CK722s and a Weller soldering
gun.
I still have the gun and it works great. IIRC the two CK722s cost
more than
the gun. When I got home I started building an audio amp for my xtal
set
and one of the leads just broke off right at the case and I didn't
mishandle it. I was finally able to a tack a lead back on. I then
mounted
the transistors on a separate pieces of wood and soldered the leads
to
fahenstock clips. Those 2 are long gone but I did find one in a junk
box at
a hamfest for free. I'm still a little hesitant to put it to use for
fear a
lead might break off. I've heard that germanium transistors don't
age well
and some kind of migration degrades their specs.
Hmmm, could be. I overhauled an HP synthesizer from the 1960's that
must have had
100 Germainum transistors in it. There must have been 10 dead ones.
I
found one
of the Motorola UHF silicon transistors (I forget, either MPSH10 or
MPSH81)
seemed to be a drop-in replacement for them. I did get it working,
but
it took way too
much time. (This unit was definitely a decade later than the CK722
vintage transistors.)
Jon
Well, let us know which model that might be so we can avoid that one in
the future. [:-)
I expect the synthesizecould be the 5100's series
(5100A, 5105A, 5110A Synth. Driver) which in fact contains a whole lot
of old germaniums. And step recovery diodes which
also are made of unobtainium ;-) (similarly seldom as tunnel diodes)
Jorgen
.
