I stopped by Dad's last night and picked up my old radio.
A Zenith 6D512. Like I thought the filters where dry.
the couling and bypass caps checked out perfect. When
Dad's friend re-capped it back then he used "orange drop"
caps. I didn't think they where around that long ago.
We had useable caps in the junk bin, so I fixed it over
lunch, and stayed a extra hour to pull a complete
alignment. The speaker cone has a small crack, that I glued
as a temp fix. But when I fired her up I was able to listen
to the BBC on 5.975. I had forgoten that I added a BFO. Crystal
controled no less. My uncle sent me a "matched" pair of mil
crystals and some house numbered Fairchild transistors, some
perfbord and the other parts. I used a 9V battery, but I think
I can steal power from the cathode in the AF output stage.
I even added a manual RF gain control. Again my uncle gave me
the diagram. He was an Air Force radar tech, who went on to become
a EE. I have ordered "proper" caps, filters and coupling/bypass,
because I don't want to burn up a RF/IF transfomer.
And a bigger shock was the KnightKit Wireless Microphone that
I completly forgoten about. A 12AX7 as a mic and phone amp,
a 50C5 as the RF oscillator/power stage, and a 50C5 as the
AF amp/modulator. I even added a seperte level control for the
phone. You where supossed ton only use a 10' antenna. But I had
much more fun with my ~100' long wire!
My wife says she now understands my interest in cryptography.
After looking at my 40 year old scriblings she says that reading
it is a job best left to the NSA.
But an even bigger shock lay in that old box. I had "air tapes"
of my some of my broadcasts. I took them to work and covertly
dubbed them CD. No way I am going to let my coworkers hear how I
sounded at 14. If I hadn't promised my Mom and wife I would have
bulk earsed then burned the old tapes. I remember that I borrowed
a friends "Norelco" open reel to reel. 7.5IPS. How professional.
It is almost funny. My voice hadn't dropped yet, so I sounded a lot
like my sister.
The Knight kit is going to require a complete overhaul. My Dad was
much smarter then I knew. He made an isolation transformer for the
hot chasies KnightKit from two back to back 120V:24V 4 amp
transformers.
I didn't understand why, all I knew is he threatened to take my toys
away
if he ever found out I was not using the transformers for the KnightKit
or the Zenith. Damn that man sure was smart 40 years ago.
I am planing on restoring the Knight to it's former glory, but I don't
think I will try a 100' antenna. While I don't use my ham license all
that much, I would hate to loose it.
Terry

wrote in message
ups.com...
I stopped by Dad's last night and picked up my old radio.
A Zenith 6D512. Like I thought the filters where dry.
the couling and bypass caps checked out perfect. When
Dad's friend re-capped it back then he used "orange drop"
caps. I didn't think they where around that long ago.
We had useable caps in the junk bin, so I fixed it over
lunch, and stayed a extra hour to pull a complete
alignment. The speaker cone has a small crack, that I glued
as a temp fix. But when I fired her up I was able to listen
to the BBC on 5.975. I had forgoten that I added a BFO. Crystal
controled no less. My uncle sent me a "matched" pair of mil
crystals and some house numbered Fairchild transistors, some
perfbord and the other parts. I used a 9V battery, but I think
I can steal power from the cathode in the AF output stage.
I even added a manual RF gain control. Again my uncle gave me
the diagram. He was an Air Force radar tech, who went on to become
a EE. I have ordered "proper" caps, filters and coupling/bypass,
because I don't want to burn up a RF/IF transfomer.

Exactly how many years did you tinker with this radio??
Seems like it was almost always in a perpetual state of
upgrade.

And a bigger shock was the KnightKit Wireless Microphone that
I completly forgoten about. A 12AX7 as a mic and phone amp,
a 50C5 as the RF oscillator/power stage, and a 50C5 as the
AF amp/modulator. I even added a seperte level control for the
phone. You where supossed ton only use a 10' antenna. But I had
much more fun with my ~100' long wire!
My wife says she now understands my interest in cryptography.
After looking at my 40 year old scriblings she says that reading
it is a job best left to the NSA.

Are you a doctor now, by any chance??

But an even bigger shock lay in that old box. I had "air tapes"
of my some of my broadcasts. I took them to work and covertly
dubbed them CD. No way I am going to let my coworkers hear how I
sounded at 14. If I hadn't promised my Mom and wife I would have
bulk earsed then burned the old tapes. I remember that I borrowed
a friends "Norelco" open reel to reel. 7.5IPS. How professional.
It is almost funny. My voice hadn't dropped yet, so I sounded a lot
like my sister.
The Knight kit is going to require a complete overhaul. My Dad was
much smarter then I knew. He made an isolation transformer for the
hot chasies KnightKit from two back to back 120V:24V 4 amp
transformers.
I didn't understand why, all I knew is he threatened to take my toys
away
if he ever found out I was not using the transformers for the
KnightKit
or the Zenith. Damn that man sure was smart 40 years ago.

I've often discovered that our parents suddenly get
a lot smarter once we get married and have kids of our
own. ;-)

I am planing on restoring the Knight to it's former glory, but I
don't
think I will try a 100' antenna. While I don't use my ham license
all
that much, I would hate to loose it.
Terry

Great job, Terry!! Keep us informed!!

--Mike L.

Michael Lawson wrote:



But an even bigger shock lay in that old box. I had "air tapes"
of my some of my broadcasts. I took them to work and covertly
dubbed them CD. No way I am going to let my coworkers hear how I
sounded at 14. If I hadn't promised my Mom and wife I would have
bulk earsed then burned the old tapes. I remember that I borrowed
a friends "Norelco" open reel to reel. 7.5IPS. How professional.
It is almost funny. My voice hadn't dropped yet, so I sounded a lot
like my sister.
The Knight kit is going to require a complete overhaul. My Dad was
much smarter then I knew. He made an isolation transformer for the
hot chasies KnightKit from two back to back 120V:24V 4 amp
transformers.
I didn't understand why, all I knew is he threatened to take my toys
away
if he ever found out I was not using the transformers for the

KnightKit

or the Zenith. Damn that man sure was smart 40 years ago.


I've often discovered that our parents suddenly get
a lot smarter once we get married and have kids of our
own. ;-)



Yeah - Mark Twain once said: "When I was 14 years old, I thought
my father was the stupidest man on the face of the earth. And when I
was 21, I was AMAZED at what my father had learned in only seven years!"

Tony

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ME a doctor? Thank goodenss NO!
I started tinkering with the radio the afternoon we got the antenna up.
A friends dad was in the NG or reserve and he gave me some "nifty"
earphones that I had to add to my radio. I still have the scar on my
right leg where I dropped a big splotch of molten solder while I was
attempting to solder the earphone jack. I was wearing shorts and my
parents were very upset, They thought I had better sense then tto work
with 700F metal while in shorts. Since the radio had an isolation
transformer that I used under pain of losing my radio, my dad just made
sure that I knew enough to stay out of the B+. It may sound like I
made all the mods in a smooth linear maner, but it was nothing that
organised. Far from it. When my uncle dropped by on his way back from
leave I asked him about these strange sounds. Tune in FSK and CW in AM
and you will see what I meant. He used his little portable trnsisotr
AM/MW/BCB Sony? as a BFO, the LO harmonics where strong enough to at
least get the point across. He made a hand drawn copy of the schematic
that dad's friend gave me the night he replaced the caps in the radio.
From that he devised some simple improvements. I was 12 years old.
Other then homework and my choes,I had a lot of free time. My parents
limited my TV watching to a few shows a week. So radio kept me out of
worse trouble. My uncle would dream up a mod and mail it too me. Those
that requried me drilling the metal chasis my dad inssited that he help
or later supervise. The little add on BFO that I built still works
fine. Even though I think crystals were overkill. My uncle sent me a
matched as in 455 +/- 1.6KHz, or KC as the crystals are labeled. I
never thought of it until this morning but the BFO makes a fine IF
peaker! I lived for radio. Dad got the Knight kit after I figured out
that I could take a FM radio, tune it to a local station, and FM the LO
by adding AF to the AFC line. Worked very well. Maybe too well. I
covered the entire subdivision. Very stable as I was locked to a
commercial station. I can't remember now if the LO was 10.7MHZ above or
below the station I was tuned to. I suspect dad would have freaked if
he had known I fed the Knight to a 100' antenna. My friends and I
scoured he area looking for radio or TVs on the curb awaiting trash
pickup. I was the talk of school when I wrangled permission to take my
sacred radio to school. Although mom made me leave the tubes at home.
Bummer. In the grade
the order came down to clean out the shop. They allowed me to go
through
the "junk" before it went to the dump. I got a WWII trainer O'scope, a
simpson that dad and I fixed that he still uses. Several micrphones.
Lotsof neat stuff.
I had to call dad at work and explain the windfall and he took off a
couple of hours early to haul the stuff home. I have the complete set
of Popular Electroincs from oct 1954, 1st issue, until Aug 1978. I
sweet talked the
school system into letting me go to vocational school starting in the
10 grade.
Radio and TV repair. Now I had no intention of fixing trashed TVs for
the rest of my life, but I saw it as the frist step toward a real
future. I went to Votech fulltime for the summers and had to go a final
4 months to get my diploma.
Then I started college. I was very lucky with great parents and
teachers that,
while they didn't have a clue, knew it and gave me pretty free reign.
You might say I still have that love affair with radio. It is sad that
as the equipment has gotten better and cheaper, the available stations
to listen to
have decreased. My Zenith was a good radio in it's day, but compared to
even my Grundig FR200, pretty far down the good scale, blows it away.
But I will keep the Zentih and use it for special listening. Like my
birthday and the holidays. I am almost afraid of what my parents will
find as they continue to clean out their home. They are planning to
sell and move to a retirement home, so if it there they will find it.
Terry

wrote:

I used to know a tv set repairman guy about fifty years ago.One evening
I got invited to have supper with his family and his tv set was the
worst looking tv set I ever saw in my life before,but it worked great
though and most of the time he had the cabinet off of his tv set,only
the chassis of the tv set sitting on a table,his tv set running just
like brand new.Caps and recaping,what does that mean? TV sets are
actually Radios,the main difference is there are cathode ray tubes with
photons "painting" the pictures on the tube.
cuhulin


My grandfather repaired radios and TVs at about the same time, and even
though he was poor he always had a TV set at a time when TVs were only
for the rich. His TVs were customer rejects-if a TV needed more repair
than it was worth the customer would say "keep it" and he'd bring it
home and fix it for his own personal use. Capacitors or "caps" are a
major part of any electronics design. Back in the tube days most caps
were made of paper and wax and tended to go bad easily. If you find an
old tube radio/TV that hasn't been used in 40 years, all the paper caps
will long since have rotted away inside and will need to be replaced in
order for the set to work. A classic indicator of just one bad cap in a
tube radio is hearing a loud hum in place of a signal.


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